Magnetic attachment is retainer that use magnetic attractive force to retain removable dentures. The use of this technology has been in clinical practice since the 1970s. Since it was covered by public insurance system in Japan in September 2021, it is expected to be used more and more. When used properly, the magnetic attachment provides retentive force and is gentle to abutment teeth, but if used incorrectly, they can cause problems and must be used appropriately. In this paper, we review the basic techniques and explain the important points.

In recent years, the fabrication of prosthetic devices is rapidly changing from the traditional method using mechanical articulators to using CAD/CAM systems. However, it was still difficult to answer clearly even which occlusal surface morphology has superior functionality. To answer the above, it is necessary to have a means to “observe and diagnose” invisible things such as dynamic occlusal contact and condylar movement, and to integrate and analyze jaw movement data and morphological data of the oral and maxillofacial region to standardize as much of “occlusion and jaw movement” as possible. In this article, we will introduce our research activities on “next-generation dental CAD/CAM system” that enables the examination and diagnosis of jaw function and the design and fabrication of prosthetic devices and explain the necessity of deeper understanding for jaw movement in the age of digital dentistry.

Dentistry based on digital technology, or so-called digital dentistry, which is driving the progress of modern dentistry, is not only improving dental medical technology, but is also fundamentally changing the very nature of dentistry. However, many clinical procedures related to jaw movement are subjective in nature, relying on the experience and skill of the dentist, and it is very difficult to reflect these in a digital workflow. For this purpose, it is necessary to collect morphological and functional information of the oral and maxillofacial region digitally, integrate and analyze them to visualize and standardize jaw movement as much as possible, and reconcile “Science” and “Art”. In this article, I would like to explain our efforts to streamline the trial-and-error part of daily clinical practice and to systematize and simplify treatment methods using “jaw movement” digital information.

Purpose: The purpose of this study was to assess the bactericidal effects of a new silver-based antimicrobial glass DL-7900 on the genus Candida, to clarify the bactericidal mechanism, and to investigate its application to denture cleansers.

Methods: 1) Disk susceptibility tests of DL-7900 for Candida species and the microbroth dilution method for determining Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) of DL-7900 for Candida albicans (C. albicans) were performed. 2) The time-dependent bactericidal effects of DL-7900 on C. albicans and the limitations on its number of times of use were investigated. 3) The bactericidal mechanism of DL-7900 on C. albicans was verified by PCR.

Results: 1) All Candida strains used in this study were sensitive to DL-7900, and MIC and MBC of DL-7900 for C. albicans were 3.9 mg/ml and 31.25 mg/ml, respectively. 2) C. albicans treated by DL-7900 for 60 minutes died out completely. The bactericidal effect of DL-7900 on biofilm-forming C. albicans was higher than that of commercial denture cleanser. Moreover, even if DL-7900 was used consecutively, the bactericidal effect did not decrease. 3) It was found that the bactericidal mechanism of DL-7900 on C. albicans was bacteriolysis.

Conclusions: Because DL-7900 showed high and long-term bactericidal activity, this material might be superior as a denture cleanser.

Purpose: The purpose of the present study was to examine how a dental technician participated remotely in the wax try-in of a complete denture and to evaluate whether the remote participation was effective.

Materials and methods: A prosthodontist placed and checked the wax trial denture of the maxilla by online communication with a remote dental technician. Later, two other prosthodontists watched a video of the wax try-in and evaluated whether the participation of the remote dental technician was effective or problematic.

Discussion: The low pixel resolution of the image made it difficult to judge the shade of artificial teeth; however, other judgments such as lip support, smile line, mold of artificial teeth, and pronunciation were successful. It is considered that the wax try-in of dentures can be performed successfully online with a remote dental technician, although separate photographs may be necessary for assessing the shade of artificial teeth.

Conclusion: The present study suggested that dental technicians working remotely from dental clinics can successfully participate online in the wax try-in of complete dentures.

Patient: A 76-year-old male presented with the chief complaint of masticatory dysfunction due to instability with immediate dentures. The patient’s mandibular anterior teeth exhibited severe attrition. Because the interocclusal relation was deep bite, the mandibular anterior teeth impinged on the maxillary anterior gingiva.

Discussion: The vertical dimension was increased within the interocclusal rest space. An occlusal contact was fabricated by expanding the framework in the lingual cusp of the maxillary molar. This resulted in long-term, stable functional and esthetic recovery using a removable partial denture with static metal occlusal surface.

Conclusion: The metal plate denture was applied to this patient with severe attrition and maxillary anterior teeth missing. It is suggested that the prognosis of the prosthesis was improved by focusing on the secondary fixation and suppression of teeth attrition.

Patient: A case report of restoring masticatory function in a patient with crossbite is described. The patient was an 80-year-old man who complained of masticatory disturbance caused by instability of complete dentures during mastication. This was caused by improper positions of artificial teeth and so the patient was given new dentures with a crossbite arrangement to improve the mechanical stability of the dentures.

Discussion: At first, preliminary jaw registration was recorded in this case to clarify whether the jaw relation was an indication of crossbite arrangement. In addition, the horizontal jaw position was determined by using Gothic arch tracing, and a functional impression was taken to attain good stability and retention, which led to high patient satisfaction.

Conclusion: It was useful to provide a crossbite arrangement for unstable maxillary dentures during use.

Patient: The patient was a 73-year-old male who complained of chewing difficulty. A decrease in occlusal support and the occlusal vertical dimension due to the progression of caries and periodontitis was observed. During the treatment period the maxillary right central incisor was fractured, and intentional adhesive replantation was performed. Occlusal reconstruction with increasing the vertical dimension was performed with provisional restorations and treatment denture, and then the final prosthetic procedures were performed.

Discussion: Prostheses with the establishment of bilateral molar support and anterior guidance reduced the risk of occlusal collapse.

Conclusion: In this case, occlusal reconstruction with increasing the vertical dimension by a cross arch bridge and removable partial denture (upper), connecting crowns and fixed partial denture (lower) was performed to recover mastication, resulting in favorable postoperative outcomes.

Patient: A 74-year-old male visited our clinic with the complaint of discomfort in the left molar region of the mandible. The cause of the chief complaint was a fracture of the mandibular left first molar, and the patient was classified as a so-called “power type patient.” In order to improve the problems of occlusal vertical dimension and occlusal plane, comprehensive prosthetic treatment with dental implants was performed.

Discussion: The application of dental implants to a patient with insufficient support elements made it possible to add a fixed prosthetic restoration to the defect and to reduce the loading on the remaining teeth. The addition of occlusal support elements by dental implants is effective in the comprehensive prosthetic treatment of power-type patients.

Conclusion: The complete prosthetic treatment with implants restored and stabilized the occlusal function.

Patient: The patient was a 67-year-old female with the chief complaint of mobility of many teeth with severe periodontal disease. Extraction of these teeth and repair of denture with additional artificial teeth were performed in two steps. After the teeth extraction wounds had healed, new complete dentures were fabricated.

Discussion: Continued adjustment of the dentures while confirming the effect of treatment using several examinations of masticatory function led to the patient’s satisfaction.

Conclusion: In this case with severe periodontal disease that needed extraction of many teeth and a change from removable partial denture to complete denture, sufficient adjustment of the form and occlusion of the previous dentures led to recovery of masticatory function with the new dentures.

Patient: This case report describes a 77-year-old male who underwent mandibulectomy, left-sided neck dissection (I-III), and reconstruction with a plate and rectus abdominis skin valve due to T4aN2bM0 gingival cancer. The patient was diagnosed with masticatory disorder due to postoperative deviation of mandibular position and decreased tongue pressure. A palatal plate was delivered as the initial treatment. A palatal augmentation prosthesis in the maxilla and an appliance for defective jaw in the mandible were made as the final prosthetic devices.

Discussion: In this case, improvement of tongue pressure and masticatory function were observed after installing the new maxillary and mandibular dentures. The dentures, which were made to have better morphology to improve mastication and swallowing, obtained satisfactory results.

Conclusion: The final prosthetic device that achieved tongue contact with the palate and functional training improved the tongue pressure and masticatory disturbance.

Patient: The patient was a 62-year-old man. His chief complaints were tooth mobility and disturbance of mastication, as well as bleeding from the gums. He had never been to a dentist before, owing to his dentophobia. Examination revealed that almost all his remaining teeth showed significant tooth mobility. At this time, immediate dentures were temporarily used as treatment dentures, and then definitive prostheses were fabricated.

Discussion: Irreversible treatment was not given at the first visit, and instead his fears were alleviated by providing careful explanations and starting with procedures with lower psychological burden. As a result, the patient quality of life has been significantly improved by the definitive prostheses.

Conclusion: As a preliminary step to prosthetic treatment, careful consultation with the patient was performed to alleviate his fears. Then, the appropriate definitive prostheses were applied, which contributed to mitigation of esthetic dissatisfaction and masticatory disturbance.

Patient: The patient was a 58-year-old male with the chief complaint of masticatory dysfunction. The maxillary and mandibular regions were classified as full edentulism-like and Kennedy classification I, respectively, after extraction of hopeless teeth. A maxillary implant overdenture (IOD) and mandibular removable partial denture with the milling technique were provided as the final prostheses.

Discussion: Application of dental implants for the maxilla and use of a partial denture with the milling technique for the mandible might help alleviate severe conditions of the maxilla and establish posterior support for the mandible by minimizing denture mobility.

Conclusion: Application of a maxillary IOD and a mandibular removable partial denture with the milling technique resulted in successful clinical outcomes.

Patient: A 76-year-old man visited complaining of pronunciation difficulties. The patient was diagnosed with right-side maxillary gingival cancer and underwent partial maxillectomy. The palatal defect had perforated the nasal cavity and maxillary sinus. The maxillary prosthesis had no sealing effect against the palatal defect resulting in rhinorrhea. Thus, the final maxillary prosthesis was designed to seal the defect tightly and form the palatal floor appropriately to resolve the problems caused by the palatal defect.

Discussion: The final prosthesis improved the patient’s single-syllable intelligibility. The inserted prostheses resulted in good outcomes in terms of chewing, swallowing, and pronunciation.

Conclusion: The closure of defects and the morphology of the palatal floor are essential to improve mastication, swallowing, and pronunciation in patients with palatal defects.

Patient: A 47-year-old female underwent maxillary subtotal resection, craniotomy, and oral reconstruction with a free muscle flap for left maxillary osteosarcoma. During the operation after the muscle transplantation, a pre-prepared removable prosthesis was fixed in the oral cavity with titanium screws, and was left attached for one month. After removal of the screws, the prosthesis was adjusted to fit the wound contraction. As the morphology of the muscular valve stabilized, the prosthesis became comfortable to use.

Discussion: Continuous use of the removable prosthesis after surgery enabled the formation of a stable palate with ideal morphology. The removable prosthesis remained stable over the long term after epithelialization and provided good esthetics and recovery of conversation and masticatory function.

Conclusion: Life prognosis is poor in patients treated with reconstruction. This minimally invasive treatment with a single operation is considered to be useful in terms of the patient’s QOL.

Patient: The female patient, who was 55 years old at the time of treatment, was suffering mandibular gingival cancer. Resection of the following parts was necessary: right hemilingual, right margin of the mandible, from the right mandibular lateral incisor to the 6th tooth of the second molar, and the buccal mucosa. Restoration of these resected parts was performed by using a forearm flap.

Discussion: Application of piezography allowed us not only to arrange the positions of the artificial teeth but also the denture base morphology in the surrounding tissue of the defective jaw and the buccal mucosa associated with scar contraction. It was also considered that the FGP technique established adequate contact during jaw engagement.

Conclusion: In this case of restoration of a jaw defect by using a forearm flap, the use of piezography and the FGP technique enabled us to produce a denture for the defective jaw, resulting in a good prognosis.

Patient: The patient was a 67-year-old female, with the chief complaints of masticatory disturbance and esthetic dissatisfaction due to attrition. After examination, the patient was diagnosed with masticatory disturbance and esthetic dissatisfaction due to attrition.

Discussion: The patient had attrition and malocclusion due to wearing an ill-fitting mandibular removable prosthesis made of metal. A definitive prosthesis was provided by reproducing the mandibular position while maintaining repeatable centric occlusion with occlusal contacts only at the upper and lower right-side canines and first premolars. In this case, the stable occlusion obtained by the definitive prosthesis with no major changes in maxillomandibular relationship led to a stable prognosis.

Conclusion: Treatment by changing from a removable prosthesis to a fixed prosthesis with no major changes in maxillomandibular relationship for attrition and malocclusion improved masticatory disturbance and esthetic dissatisfaction.

Patient: A 21-year-old female patient who had poor esthetics due to a missing maxillary right central incisor was treated using a fixed dental prosthesis with modified ovate pontic combining minor tooth movement and localized alveolar ridge augmentation.

Discussion: After tooth positioning by minor tooth movement, localized alveolar ridge augmentation was performed using a provisional fixed dental prosthesis for esthetic designings. After periodontal surgery, modified ovate pontic and mucosa were harmonized, and the esthetic problem was considerably improved. The stability of mucosa shape was confirmed during the temporary cementation period of 5 years and 11 months. As a result, the outcome has remained stable to date at 10 years and 6 months.

Conclusion: For a maxillary incisor missing patient with ridge defects, the interdisciplinary approach combining local orthodontic treatment, minor periodontal plastic surgery and fixed dental prosthesis with modified ovate pontic provided satisfactory long-term stability with good esthetics.

Patient: A 51-year-old female complained of esthetic problems and difficulty with mastication caused by repeated fracture and detachment of an interim bridge and ill-fitting of a removable partial denture (RPD). Based upon clinical examination, she was diagnosed with sleep bruxism. A Konus telescopic denture and dental implant crowns were provided for the maxilla and the mandible, respectively. During sleep, she was advised to wear another splint-like RPD (night denture).

Discussion: The Konus telescopic denture allowed her to recover masticatory function because of its appropriate retention and stability and esthetic appreciation owing to lip support by the denture base.

Conclusion: The prosthodontic treatment with the Konus telescopic denture and dental implant crowns effectively restored esthetic appreciation and masticatory function. The night denture reduced the overload on the abutment teeth caused by sleep bruxism, which may have contributed to success for a certain period.

Patient: A 72-year-old male patient presented with the chief complaint of masticatory disturbance due to damage to his removable partial denture and missing mandibular right and left molars. He had mandibular torus in the right and left canine to first premolar area. A metal-based removable partial denture made of Co-Cr using a lingual plate was fabricated without surgical treatment.

Discussion: Insertion of the removable partial denture improved the occlusal relationship and functional stability, and the use of a metal-based denture minimized the patient’s discomfort.

Conclusion: The application of an adapted metal-based denture considering the design of the major connector to partial edentulous regions with mandibular torus resulted in a satisfactory therapeutic effect.

Patient: The patient was a 46-year-old man who visited the clinic complaining of the appearance of his anterior teeth. The patient was diagnosed as having esthetic impairment due to missing maxillary left central and lateral incisors. An all-ceramic bridge with zirconia copings and porcelain was used for prosthetic treatment of the missing teeth. The anterior guidance of the all-ceramic bridge was fabricated by referring to that of the initial prosthesis confirmed as having no functional abnormalities.

Discussion: By reflecting the anterior guidance at the initial visit, the all-ceramic crown was fabricated, resulting in patient satisfaction with esthetics and function.

Conclusion: An all-ceramic bridge was fabricated, and good esthetic and functional results were obtained.

Patient: The patient was a 40-year-old female with a chief complaint of masticatory disturbance with a deficit of |4 and esthetic dissatisfaction with a deficit of |4 and maxillary anterior teeth. Mild crowding and unsuitable form in the anterior teeth, low brightness due to nonvital teeth of 32|23, and shade mismatching with composite resin filling were observed. Those teeth were esthetically improved with all-ceramic crowns and a fixed partial denture.

Discussion: Sharing images before treatment by diagnostic wax-up and gradual modification of a provisional restoration based on patient subjectivity resulted in high satisfaction of the patient.

Conclusion: A step-by-step treatment procedure in line with the patient’s high esthetic demands led to a favorable outcome.

Patient: The patient was a 70-year-old male who had masticatory disturbance due to movement of a maxillary bridge and multiple tooth defects. Final prosthodontic treatments were performed after improving the occlusal vertical dimension by using a provisional restoration and a treatment denture, and by educating and motivating the patient for dental treatment.

Discussion: In this case, pre-surgical and pre-prosthetic treatments were important steps for the final prosthodontic treatment and also provided an opportunity to establish a relationship of trust. In addition, by providing intrinsic motivation, the patient’s motivation for treatment was maintained.

Conclusion: Prosthetic treatment was achieved through effective pre-treatment and intrinsic motivation, and a stable postoperative course was obtained.