My relationship with maxillofacial prostheses began in 1986 when I was in charge of a patient with partial maxillary resection. While considering the treatment plan, I came across the Journal of Maxillofacial Prosthetics and immediately joined the Society. The case that I treated was presented at the Annual Meeting.
The problems at that time were as follows: 1） We could not deal with facial defects. 2） In some patients, the defective palate was covered with a flap, so undercutting of the defect could not be used for retention. 3） In patients with partial maxillary resection, we could not use the healthy central incisor as an abutment tooth. 4） When the mandibular defect area was covered with tongue tissue and sutured to the buccal mucosa, it was impossible to make an appropriate removable prosthesis.
These results showed that surgery was being led by otolaryngology and oral surgery and preoperative discussions with prosthodontists were not held; this seemed to be the biggest problem at that time.
In order to help patients, researchers at the Japanese Academy of Maxillofacial Prosthetics have extracted various problems and have been studying breakthrough measures.
The importance of dento-maxillary prostheses has been emphasized, and new technology has been introduced with each revision of the insurance system. Therefore, to consider future insurance revisions, this study aimed to clarify how introduced technology has affected the actual state of insurance medical care for maxillofacial prostheses.
Based on the results of the survey by social medical practice （Ministry of Health, Labour and Welfare） from 2011 to 2020, the changes in the number of dento-maxillary prostheses and PAPs were tabulated, and the relevance to the contents of the insurance revision was considered.
Dento-maxillary prostheses decreased sharply in 2013, but increased from 2014 and remained flat after 2015 （about 300 cases/month）. However, the number decreased in 2020. PAP increased gradually from the time of introduction in 2014 to 2017, and has not changed much since then （about 100 cases/month）.
With the introduction of new insured technology, dento-maxillary prostheses have been enhanced and have also increased quantitatively to some extent, but there are still many unclear points in the actual situation. It is also suggested that dento-maxillary prostheses may not have been adequately delivered to patients in need.
Materials in oral appliances used to protect teeth during tracheal intubation were compared and considered. Hard materials have strength but require time to prepare. Hard material with a thickness of 0.8mm （0.8H） scored the highest in compatibility and in the compression test. However, it is not considered suitable for patients with poor motor skills or unstable teeth, due to difficulty in insertion/removal, and constriction. Soft materials can be more easily constructed for an appliance but have lower strength. In addition, soft material with a thickness of 2.0mm was extremely loose and interference with intubation operation was of concern. Soft and hard materials with a thickness of 2.3mm （2.3SH） and soft material with a thickness of 3.0mm had good compatibility. Insertion and removal were simple. In consideration of visibility during intubation, 2.3SH was more suitable.
From the above results, it is suggested that oral appliances used to protect the teeth during tracheal intubation should be made of 0.8H or 2.3SH. In particular, 2.3SH is considered applicable to all cases, although it is expensive．
Maxillary defects caused by surgical resection of the jaw can sometimes significantly impair vital functions such as articulation and food intake. When functional restoration, such as that achieved with a dento-maxillary prosthesis （prosthetic reconstruction）, is selected for maxillary resection, an intraoral apparatus is required to improve the residual disorder. In our department, the intraoral apparatus is prepared before surgery, and intervention is started early for cases in which prosthetic reconstruction was determined at the preoperative clinical conference with departments related to head and neck surgery. The present case suffered from an edentulous unilateral maxillary defect, an obturator was fabricated twice using the method of directly relining the base plate, which was made using a polyethylene terephthalate （PET） sheet （by means of the base plate relining method）, and early restoration of oral function was achieved. Since the base plate relining method facilitates repeat fabrication, it seems useful for managing maxillary wounds. The prosthetic reconstruction method was established with multidisciplinary medical staff. The perioperative prosthetic management method is reported from the perspective of a dental clinician engaged in oral functional restoration.
Maxillofacial prosthetic treatment with obturator prostheses has contributed to improvements in speech, mastication, swallowing, and early return of patients to society. To establish more effective maxillofacial prosthetic treatment, it is desirable to develop a new material with high reproducibility of the detailed shape of maxillary defects, high adaptability to tissue changes over time, and high biocompatibility. This study focused on shape memory gel （SMG）. SMG has unique properties: it softens when heated, maintains its shape when cooled, and returns to its original shape when reheated. The aim was to evaluate the physical properties of SMG for dental application. Specimens were prepared by changing the polymerization initiator camphorquinone （CQ） and the mixing ratio of the two monomers stearyl acrylate （SA） and lauryl acrylate （LA） of SMG, and the memory properties were examined. Switching the polymerization initiator of SMG to CQ enabled polymerization with dental photopolymerization devices. Changing the combination ratio of SA to LA enabled adjustment of the tensile strength. It was confirmed that the shape memory property, an original characteristic of SMG, was maintained, and physical properties similar to those of existing dental materials were obtained.
An 82-year-old female visited our department after marginal mandibulectomy in the left premolar and molar area due to squamous cell carcinoma. She was completely edentulous in the maxilla and was categorized as Kennedy ClassⅡ in the mandible. She was rehabilitated with a complete denture and a unilateral free-end removable partial denture （RPD）. However, she complained of pain in the resected area and avoided using her mandibular RPD, followed by tongue-mucosa adhesion and a phonetic problem. After surgical intervention, instability of the RPD was still observed due to mandibular morphology after marginal mandibulectomy. To solve this problem, a four-unit fixed partial denture was changed into two single crowns （porcelain fused to metal crowns） with guide planes and an RPD for Kennedy ClassⅡ modification was fabricated. This RPD provided stability and improved her oral functions. Although the clinical course looked fine, wear of the artificial teeth depending on the material properties was associated with denture instability and occlusal problem. After a 3-year observation period, a maxillary denture with metal cusp and palatal plate was fabricated, resulting in better stability. This case report demonstrated that modifying the RPD design contributed to stability in a patient after marginal mandibulectomy.
A 33-year-old female with odontogenic myxoma in the left-side mandible was referred by a head and neck surgeon for preoperative examination and postoperative mandibular prosthesis preparation. A multidisciplinary approach was provided: tumor resection by an otolaryngologist, free peroneal flap reconstruction by a plastic surgeon and oral surgeon, and prosthesis for defective jaw by a dentist. A three-dimensional skull model and oral appliance for intermaxillary fixation were used in surgical reconstruction to restore the maxillomandibular relationship and intercuspal position. A prosthesis for defective jaw was fabricated after the postoperative wound healing period and adjusted to gain stability. The improvement of masticatory ability on the affected side was relatively low one year after delivery of the prosthesis. However, occlusal force was obtained with the prosthesis, and oral health-related QOL was greatly improved six months after delivery of the prosthesis. The maxillomandibular relationship was not changed seven years and three months after the operation. The multidisciplinary team collaborated closely and contributed to improving the patient’s QOL, and the prosthesis for defective jaw improved oral functions.
The patient was a 66-year-old woman who was referred to our Department of Otolaryngology at Kansai Medical University with the suspicion of nasal tumor and underwent endoscopic nasal surgery in 2013. Recurrence was observed in the palate in 2017, and subtotal palate resection was performed by an otolaryngologist. After the surgery, she was referred to our department and treated with a dento-maxillary prosthesis. In the same year, a partial maxillary resection was performed by the otolaryngologist as an additional procedure; therefore, the dento-maxillary prosthesis was refabricated. Furthermore, because another recurrence was observed, subtotal maxillary resection and rectus abdominis musculocutaneous flap reconstruction were performed. As additional surgery was repeated, the range of maxillary defects expanded, and it became more difficult to fabricate the prosthesis. Due to the oral environment, it became extremely difficult to fabricate the prosthesis. Eventually, although sufficient improvement was not achieved for speech and masticatory disorders, patient satisfaction with the improvement of esthetic disorders was obtained.