Combination syndrome, a well-known specific condition in the patient with edentulous maxilla and partially edentulous mandible with only anterior teeth, has been recognized as anterior hyperfunction syndrome. Although anterior hyperfunction has not been defined clearly, it is supposed to describe anterior hyperfunction as excessive occlusal force by residual mandibular anterior teeth. This is not limited to Eichner C2 (edentulous maxilla and partially edentulous mandible), which typically shows combination syndrome, but is also observed in Eichner C1 and B4 patients. Anterior hyperfunction is attributed to weakening or loss of posterior occlusal supports, and reduction of vertical dimension of occlusion in many cases.

This article aims to describe oral conditions induced by anterior hyperfunction and to discuss etiology and clinical managements.

Anterior hyperfunction (AH) is defined as excessive occlusal forces in the anterior teeth in B4 and C1 cases as well as in Eichner C2 cases with combination syndrome. The most difficult cases to deal with are generally those in which the occlusal contact caused by excessive occlusal forces is not properly managed, leading to denture sway, changes in occlusal contact, and changes in periodontal tissues, leading to further destruction of the oral tissues. The treatment strategy is to restore the occlusion of the molars and to control the occlusal forces of the anterior teeth. This article discusses the treatment and maintenance of AH cases in denture prosthetics, focusing on clinical techniques.

Anterior hyperfunction syndrome is a situation in which the remaining lower anterior teeth generate excessive occlusal forces due to the lack of occlusal support of the upper and lower molars. In these cases, it is important to restore stable occlusal support to the molars and control the occlusal forces applied to the anterior teeth. For this purpose, prosthetic treatment using implants is one of the most effective options. However, even if prosthetic treatment using implants is performed, complications with the implant body and superstructure may occur, so the treatment planning, prosthetic design and occlusal adjustment must be carefully checked.

Among the classification of temporomandibular disorders (TMDs), TMD myalgia is characterized as a painful condition in the masticatory muscles, associated with disfunction of the jaw. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), the internationally standardized diagnostic criteria for TMD, was announced by the International Network for Orofacial Pain and Related Disorders Methodology (INfORM) f.n.a. International Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Consortium Network in 2014. DC/TMD allows even non-experts in orofacial pain to give an accurate diagnosis of TMDs. For the management of TMDs, conservative options such as oral appliance therapy, physiotherapy, and medication, should be taken priority over the irreversible options. In this article, basic knowledge, diagnostic process, and management of TMD myalgia are to be explained.

The basic management of TMD should begin with explanation of the pathophysiology and home-care instruction, followed by non-invasive treatment, mainly physical therapy, pharmacotherapy, and appliance therapy. Since occlusal therapy has no advantage over reversible therapy, any treatment that irreversibly alters occlusion should be avoided.

On the other hand, there are cases in which patients present with secondary occlusal disorders, such as an anterior open bite, after temporomandibular joint disorders have healed, and prosthetic treatment is required when patients complain of severe masticatory disorders.

This paper focuses on three points: 1) Current treatment concepts for TMD, 2) Symptom-specific methods of using occlusal appliances, and 3) Prosthetic treatment of TMD-related occlusal dysfunction.

Full digital workflow from impression taking to the prosthesis fabrication is possible without the use of intermediate materials in the fabrication of fixed prosthesis. On the contrary, the digitalization of removable denture fabrication will be almost performed in the dental laboratory side, but the digitalization of impression taking and occlusal registration for removable denture treatment has not been fully realized. This article discussed current status and prospect on the digitalization of removable denture treatment from the following viewpoints: impression taking, occlusal registration, denture design and arranging teeth, framework fabrication, integration of denture components, and denture duplication. In addition, the genuinely significance of “Digital Transformation (DX)” and ”Smart Prosthodontics” were also discussed.

Patient: A 65-year-old woman visited complaining of difficulty in chewing and esthetic failure because of the attrition of artificial teeth in the complete dentures. It was explained that confirmation with treatment dentures was essential due to high esthetic demands, however, the patient requested to receive definitive dentures immediately. Therefore, after relining and occlusal reconstruction of the old dentures, new complete dentures were made, and any additional esthetic requests were dealt with by repairing.

Discussion: After confirming the stability of the repaired old dentures, the horizontal mandibular position was examined using the gothic arch tracing method during the fabrication of the new complete dentures. Also, the esthetic demands were adequately met during the maintenance period. As a result, good progress was obtained.

Conclusion: High patient satisfaction was achieved through stabilizing the old dentures and appropriately meeting the esthetic demands after wearing the new dentures

Patient: The patient was a 64-year-old male who came to our clinic with a chief complaint of masticatory disturbance and poor esthetics of a removable partial denture. The occlusal plane and occlusal vertical dimension were not appropriate, and the habitual occlusal position was unstable. The treatment removable partial denture was delivered before implant placement to restore masticatory function. After stable occlusion was achieved, implant placement and bone augmentation were conducted based on prosthetic-driven planning. Finally, the fixed implant-supported prosthesis was delivered.

Discussion: This case was almost non-vertical stop occlusion, making it important to reconstruct the inappropriate occlusal plane and vertical occlusal dimension by a treatment denture before the fixed restoration. The number and position of implants should be decided based on the prognosis of other teeth and patient demands.

Conclusion: Good results were obtained by the treatment denture and fixed implant-supported prosthesis, which restored esthetics and masticatory function, and improved the patient’s oral health-related QoL.

Patient: A 73-year-old male presented with the chief complaint of poor esthetics and masticatory disorder due to fracture of the maxillary right central incisor tooth. Upon examination, a molar defect, crown fracture, and moderate wear over multiple teeth were found, resulting in an irregular occlusal plane and insufficient anterior prosthetic clearance due to a decrease in the occlusal vertical dimension. The patient’s masticatory function and esthetics were improved by bite raising and correcting the occlusal plane.

Discussion: After correcting the occlusal vertical dimension and occlusal plane based on anatomy with temporary restoration, the patient’s masticatory ability and esthetics were evaluated over a sufficient observation period, which is considered to have resulted in a good outcome.

Conclusion: Good results were obtained by performing bite raising for insufficient clearance of the anterior prosthetic.

Patient: A 76-year-old man visited our hospital with the chief complaints of anterior reverse occlusion and accidental biting of the upper lip. At the first examination, his anterior occlusion was reverse and the median lines of his face and teeth were mismatched. An overdenture was applied in order to improve the chief complaints.

Discussion: After the final dentures were delivered, appropriate lip support was obtained, esthetics were improved, and accidental biting of the upper lip disappeared. It is considered that the main cause of accidental biting was the lack of anterior overjet.

Conclusion: The treatment with an overdenture resulted in rapid improvement. Approximately 5 years after treatment, the patient remains highly satisfied.

Patient: The patient was a 55-year-old woman who complained of poor esthetics and difficulty in mastication due to debonding of the anterior fixed partial denture. A full-mouth reconstruction was performed using all-ceramic crowns and fixed dental prostheses because of the loss of the maxillary anterior lingual dentition due to endogenous erosion and reduction in the vertical occlusal height.

Discussion: Due to the insufficient denture space in the missing maxillary anterior tooth, a provisional restoration was fabricated based on the diagnostic wax-up to determine the final prosthetic design.

Conclusion: Full-mouth prosthodontic treatment with all-ceramic crowns and fixed dental prostheses was performed for the missing dentition with endogenous acid erosion and bruxism to restore esthetic and occlusal function, with a good prognosis and high patient satisfaction.

Patient: A 78-year-old female patient presented with the chief complaint of repeatedly broken dentures and difficulty in mastication due to incompatible dentures. The patient had flabby gum in her maxillary anterior teeth and experienced pain in that area upon waking up. A removable partial denture made of cobalt-chromium (Co-Cr) alloy was fabricated, and a night denture was prescribed for her sleep bruxism.

Discussion: It is considered that prosthetic treatment improved masticatory function and contributed to high patient satisfaction.

Conclusion: The patient expressed satisfaction with the new metal plate denture that was created using a pressure-free functional impression technique. Additionally, the use of the night denture for the patient’s bruxism appeared to have improved the prognosis of the prosthesis.

Patient: A 55-year-old female patient visited our clinic with the chief complaint of repeated detachment of a maxillary anterior bridge. Since post-extraction examination revealed significant bone resorption in the maxillary anterior region, bone augmentation and implant placement were performed. Then, a superstructure for dental implants was installed.

Discussion: So far, no symptoms with the soft and hard tissues surrounding the implant have been observed. However, it is necessary to monitor the bone resorption due to less keratinized mucosa.

Conclusion: It was possible to secure an ideal amount of bone both horizontally and vertically by combining autologous bone and artificial bone grafts, resulting in greater esthetic improvement and higher patient satisfaction.

Patient: A 77-year-old female patient complained of significant masticatory dysfunction despite treatment with removable dentures after the removal of dental implants in the maxilla and mandibular molar area. In order to restore masticatory function, implant-supported fixed prosthodontic treatments were reapplied to the missing teeth in the maxilla and mandible, and fixed prosthodontic treatments were applied to the remaining teeth in the mandible.

Discussion: Patients with a history of implant treatment might experience masticatory dysfunction and discomfort caused by removable prosthodontic treatment. It is therefore considered that the reapplication of an implant-supported fixed prosthodontic treatment was effective.

Conclusion: In the present case of masticatory dysfunction which was not improved by removable prosthodontic treatment, the implant-supported fixed prosthodontic treatment contributed to the restoration of masticatory function and improvement of patient satisfaction.

Patient: A 62-year-old woman complained of difficulty of mastication due to the movement of a maxillary anterior denture. The patient had occlusal contact only on the right premolars and used a removable partial denture on her maxillary anterior and mandibular molars. A fixed implant-supported partial denture successfully restored masticatory function in non-vertical stop-like occlusion and maintained the stability of the remaining teeth.

Discussion: The fixed implant-supported denture increased the occlusal-supporting area and contributed to the restoration of masticatory function in the patient who had non-vertical stop-like occlusion.

Conclusion: Functional restoration using a fixed implant-supported partial denture was successfully achieved in a patient with a non-vertical stop-like occlusion.

Patient: A 64-year-old woman visited the clinic with the chief complaints of poor esthetics due to gingival recession and caries, and difficulty on mastication caused by decreased function and occlusal pain. She was suspected to have severe periodontal disease, damage to the occlusal surface of the crown prosthetics, and loss of height due to attrition. The patient was treated with a provisional restoration for bite raising, and after follow-up observation, the final prosthetics was placed.

Discussion: The use of a provisional restoration to fully confirm the occlusion and stabilize the periodontal tissues may have led to the restoration of good esthetics and masticatory function.

Conclusion: The patient was treated with the final prosthetics after correcting the bite raising and occlusal plane, which helped maintain it for a long period of time.

Patient: A 76-year-old female patient presented with difficulty in chewing due to ill-fitting dentures. An overdenture was present in the maxilla, while a partial denture was worn in the mandible. The occlusal plane was severely disrupted, resulting in denture movement during chewing. To address this issue, treatment dentures were fabricated to stabilize the occlusion, followed by the production of final prostheses for the maxilla and mandible.

Discussion: Transitioning from treatment dentures to the final prostheses allowed the fabrication of highly predictable restorations, leading to improvements in oral-related quality of life and satisfaction with the dentures.

Conclusion: Treating this patient with a disrupted occlusal plane by using treatment dentures to ensure occlusal stability and subsequently creating final prostheses achieved a favorable outcome.

Patient: The patient was a 70-year-old male who came to our hospital complaining of chewing difficulty due to teeth movement. Resorption of alveolar bone in the whole jaw and movements of multiple teeth caused by severe chronic periodontitis, mismatches and secondary caries of crown margins were observed. After periodontal treatment using treatment dentures and judging the predictability of the remaining teeth, the upper jaw was fitted with a complete titanium-based denture, the lower jaw was fitted with a Konus Krone denture, and the occlusion was reconstructed.

Discussion: Due to the secondary splinting effect and easy cleaning of the Konus Krone denture, the remaining teeth maintain good periodontal tissue condition.

Conclusion: A stable prognosis with improved mastication was achieved with the complete denture and the Konus Krone denture after periodontal treatment.

Patient: The patient was a 78-year-old female who visited our hospital with complaints of masticatory disturbance due to ill-fitting dentures and esthetic issues involving her frontal maxillary teeth. An irregular occlusal plane due to tooth elongation, a dental prosthesis with an unsuitable shape in the maxillary incisors, and a lower denture with insufficient retention and support were observed. After adjusting her occlusal plane using a virtual articulator, fixed prostheses involving dental implants and overdenture were applied to her maxilla and mandible, respectively.

Discussion: The virtual articulator is a valuable technique for efficiently and accurately conducting prosthetic procedures, from occlusal examination to the fabrication of provisional restorations and final prostheses that reflect biological information obtained from provisional restorations.

Conclusion: The virtual articulator made it possible to provide esthetic dental prostheses harmonized with her function.

Patient: A 67-year-old female presented with esthetic concerns due to occlusal attrition. Following examination, she was diagnosed with esthetic dissatisfaction resulting from attrition and underwent prosthetic restoration.

Discussion: After increasing the vertical dimension and adjusting the provisional restoration, esthetic issues were addressed using both fixed and removable dental prostheses. Porcelain layering zirconia and monolithic zirconia crowns were chosen as fixed prostheses, and a metal-based denture was used as a removable prosthesis, resulting in improved esthetics.

Conclusion: The patient was satisfied with the improved esthetic restoration and the selection of an appropriate final prosthesis.

Patient: The patient, a 59-year-old man, came to our hospital with a chief complaint of missing teeth and difficulty chewing. The patient was diagnosed with masticatory disorder due to partial loss of the mandibular dentition following mandibular resection of mandibular gingival cancer. We fabricated new dentures and restored stable occlusion to restore masticatory function and improve masticatory disorders.

Discussion: Functional adjustment of the dentition improved the occlusal contact area and increased the occlusion force, and the chewing cycle stabilized. The improvement was verified by chewing ability tests and chewing evaluation using Hirai’s food intake survey.

Conclusion: Proper denture placement in patients with jaw defects is thought to ensure a stable occlusal relationship, improve occlusal force, and restore masticatory ability, thereby contributing to the improvement of masticatory disorders.

Patient: A 56-year-old male presented with discomfort with the right mandible bridge and difficulty in mastication. The patient was diagnosed with masticatory dysfunction caused by tooth mobility due to severe periodontal disease. The final denture design was considered through the treatment and a provisional denture, and subsequently the treatment progressed with a telescopic crown-retained removable partial denture.

Discussion: The use of a telescopic crown for secondary splinting was considered successful in improving mastication. In addition, it was observed that the ease of plaque control on the abutment teeth contributed to maintaining the patient’s motivation for oral hygiene. Improved patient satisfaction, oral health, quality of life, and masticatory performance were achieved after the treatment.

Conclusion: It was considered that the telescopic crown-retained removable partial denture effectively improved masticatory function.

Patient: The patient was a 54-year-old female with the complaint that she could not chew well due to movement of her anterior teeth, which made swallowing difficult and unsightly. After various examinations, the patient was found to have mastication disorder due to the movement of her maxillary anterior teeth. The lower jaw was not stable and the hyoid bone position was declining, resulting in decreased swallowing function, with esthetic disorder. Prosthetic treatment and indirect training improved the swallowing function.

Discussion: We were able to reduce the risk of dysphagia of this patient who had been unable to eat well by identifying and treating her chewing and swallowing problems.

Conclusion: It is important to diagnose and approach swallowing dysfunction at the stage of recovery as well as prosthetic treatment in order to prevent dysphagia.

Patient: A 60-year-old woman visited our hospital complaining of movement and pain in the maxillary right molar region during mastication. Masticatory dysfunction was diagnosed due to abutment tooth movement due to severe periodontal disease and denture instability caused by protruding teeth. While performing basic periodontal treatment, the abutment teeth and abutment device were selected using the treatment denture, and a telescopic crown was delivered as the final dental prostheses.

Discussion: By using the treatment denture, the morphology and function of the prosthetic device were verified, and based on that information, the final denture led to good results.

Conclusion: By using the treatment denture, the selection of abutment teeth and abutment device was verified, and good results for the final prosthesis were obtained.

Patient: A 54-year-old woman was suffering from difficulty chewing due to the detachment of crowns and missing teeth. The missing teeth were treated with dental implants, and all-ceramic crowns were placed after endodontic treatment of the teeth where the crowns had become detached. Minor tooth movement was performed on the maxillary anterior teeth. Finally, teeth whitening was conducted to complete the treatment.

Discussion: The patient achieved improved functional and esthetic oral condition through various treatments. Occlusal support of the molars was increased with implants, the anterior canal relationship was improved through minor tooth movement, and prosthetic treatment with all-ceramic crowns was performed after teeth whitening.

Conclusion: In this case, an interdisciplinary approach involving collaboration among orthodontics, prosthodontics, and conservative dentistry led to a favorable outcome.

Patient: The patient was a 61-year-old woman complaining of eating and speaking difficulties. Although she had defects in her molar region, she did not use a removable denture due to discomfort and esthetic issues. We found that the opposing tooth had protruded due to the defect being left untreated, and it was determined that the occlusal plane needed to be corrected, so we performed treatment using a fixed implant denture. Three years have passed since the final prosthesis was installed, and the patient is functionally and esthetically satisfied.

Discussion: Prosthetic treatment after evaluation of function through provisional restoration led to high patient satisfaction.

Conclusion: For this patient who was unable to use removable dentures due to discomfort and esthetic issues, functional recovery using implant-supported fixed dentures was confirmed to be an effective treatment method.

Patient: A 72-year-old male patient visited our clinic with a chief complaint of masticatory disturbance and poor esthetics. Dysmasesis with infraocclusion caused by severe tooth-wear was found. The vertical dimension was evaluated by using a treatment denture. Root canal treatment and clinical crown-lengthening were performed for the upper anterior tooth and provisional restorations were delivered. After stable occlusion and gingival condition were achieved, the final prosthesis was delivered.

Discussion: In this case it was necessary to increase the vertical height to achieve appropriate anterior guidance and facial appearance. The key was evaluating the elevation of vertical height by applying a reversible treatment.

Conclusion: Stable masticatory function and esthetics could be obtained by determining the appropriate occlusal height with a treatment denture for this case with infraocclusion.