Today, digital technologies in dentistry provide general practitioners many advantages and are required accuracy. Implant sur-gery should be performed not allowing the implant to cause any harm to its surrounding tissue. And then implant superstruc-tures are d emanded the accuracy as precision parts. This article describes how to apply the clinical decision to implant surgery and prosthodontics based on the instructions and the research of the predecessor and according to the purp ose of four restora-tion treatments by Frank Spear et al.

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Purpose: The systemic effects of sleep apnea syndrome （SAS） are becoming a social issue as well as a medical and dental prob- lem. This is a social issue as well as a medical and dental problem, and therefore, it should be taken into consideration in interdis- ciplinary approach. This presentation will discuss cases of occlusal reconstruction from the prosthodontist’s point of view, taking into consideration not only esthetics and function, but also airway. I will also introduce the Morphological Tooth Augmentation Procedure （MTAP）, a new concept that is a variant of the recently popular vertical abutment tooth preparation （BOPT）, and a less invasive prosthetic design based on the concept of MI. Conclusion: Before prosthetic treatment after maxillofacial orthognathic surgery for patients with SAS, it is important to avoid obstruction of the airway by the shape of the prosthetic device. The restorative treatment was performed using MTAP （Morphological Tooth Augmentation Procedure）, a less invasive concept based on the concept of MI, and good results were obtained. The systemic effects of sleep apnea syndrome （SAS） are becoming a social problem as well as a medical and dental problem. This is an issue that needs to be taken into consideration in interdisciplinary approaches. In this presentation, I would like to explain a case of occlusal reconstruction from the prosthodontist’s point of view, considering not only esthetics and func- tion but also airway.

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Purpose: In 2018, the American Academy of Periodontology and the European Federation of Periodontology jointly published a new classification of periodontitis. The definition of periodontitis was reorganized and its evaluation methods were also changed to stages and grades. The purpose of this study was to determine the prevalence of periodontitis and the proportion of patients with severe periodontitis (stages III and IV) among Japanese dental patients in a multicenter cross-sectional study. Methods: Patients (male and female) aged 35 years or older who made a first visit to 12 general dental clinics during a 6 -month period from August 2021 to February 2022 were included in the study, and the new classification of periodontitis was applied. Results: The total number of subjects was 344 (144 males and 200 females), and the mean age at the first visit was 51.9 ± 12.1 years. The prevalence of periodontitis was 75.9%, and the proportion of patients with severe periodontitis (stages III and IV) was 48.3% (among patients with periodontitis) and 39.5% (among all subjects). There was a correlation between age and severe periodontitis. Conclusions: The prevalence of periodontitis and the proportion of patients with severe periodontitis (stages III and IV) were high in patients who visited general dentists for the first time.

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Purpose: This study aimed to clarify the effect of interproximal distance between adjacent teeth on the accuracy of digital impressions using an intraoral scanner for the preparation design of laminate veneers. Methods: Maxillary abutment teeth models with 0, 0.3, 0.5, 0.7, 1.0-, and 1.2-mm interproximal space between central incisors, central and lateral incisors, lateral incisors and canines, and canines and first premolars were prepared as a master models. Two operators with different levels of experience took 10 times scanning of all master models using an intraoral scanner. From all of the digital models, the distances between abutments were measured at three points in each interproximal space (top, middle, and bottom) using computer-aided design software. Results: Regarding comparisons of interproximal spaces, the space between the central and lateral incisors showed the highest trueness. Regarding the comparison of the amount of space created, 0.7 mm showed the highest trueness, followed by 0.5 mm. In terms of the measurement section, the top (incisal side) showed the highest trueness, and the degree of trueness decreased toward the cervical side. The comparison by operator experience revealed higher trueness and precision by the more experienced operator. Conclusion: These findings indicate that > 0.5 mm of interproximal space is essential to take digital impressions using an intraoral scanner and create accurate three-dimensional models.

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Purpose：A cross-sectional study was performed to clarify the relationship between mandibular anterior crowding and gingival recession in adult patients aged over 40 years． Methods：Data was included the mandibular anterior crowding, bleeding on probing（BOP）, pocket depth（PD）, clinical attach- ment loss（CAL） from 55 patients over 40 years who started orthodontic treatment, except smokers, diabetes, and other general diseases. Results：There was a significant difference （P=0.0000371） in gingival recession between the group with over 5 mm and less than 5 mm. There was a correlation between the amount of gingival recession and the amount of crowding （Spearman correla- tion coefficient 0.528）. Conclusion：This study suggests adults mandibular anterior crowding may be one of the causes to happen gingival recession at the same site．

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Patients：A 65-year-old female. The patient’s main complaints were improvement of the existing prosthesis and full mouth treatment. During a medical interview, the patient reported that she was undergoing treatment for reflux esophagitis and that she snored during sleep. A questionnaire survey and sleep evaluation device revealed that the patient had mild obstructive sleep apnea. Intraoral examination revealed that all existing prostheses were inadequate, and there was dentin exposure due to acid erosion, gingival recession and loss of cervical dentition around the entire circumference of the tooth. The upper and lower dental arches were stenotic, narrowing the lingual tufts. To reduce airway obstruction by the tongue, we proposed full orthodontic treatment to enlarge the dentition, but the patient did not give consent. So we performed a prosthetic mouth rehabilitation. The crowns of the upper and lower molars were tilted buccally from the original tooth axis in the form of a prosthetic appliance, and the dentition was enlarged. Comparison of lateral cephalometric radiographs taken before and after the prosthetic treatment showed that the anteroposterior diameter of the air- way was enlarged. Sleep evaluation device examination revealed moderate obstructive sleep apnea. An oral appliance with a mandibular forward movement of 6 mm was fabricated, and a re-evaluation after the patient started using the appliance showed improvement of obstructive sleep apnea symptoms. After completion of treatment, the patient continues to be monitored for occlusion and sleep status. Discussion：The anterior-posterior diameter of the upper airway was enlarged by correction of the mandibular position, which resulted in an anterior traction of the hyoid bone by the suprahyoid muscles attached to the mandible, and the construction of a dentition that did not obstruct the lingual tuft. Oral appliance is a symptomatic treatment with the risk of occlusal changes. The effectiveness of the treatment is affected by a combination of fac- tors, including weight fluctuations and hormonal effects on the activity of the upper airway opening striae. Unlike conventional prosthetic treatment, more careful follow-up is important because many items are subject to postoperative reevaluation. Conclusion：Pre- and posttreatment comparisons confirmed that the prosthetic device enlarged the dentition and the anterior-posterior diameter of the upper airway, but mouth rehabilitation alone did not solve all the problems. The fabricated oral appliance improved obstructive sleep apnea, but careful follow-up is necessary to avoid occlusal changes.

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Patients: The patient was a 40-year-old male. He visited our dental office with chief complaint of terrible headache, stiff neck, insomnia, nose obstruction feel and panic syndrome since receiving orthodontic treatment 10 years ago. His upper both canines were worn and had remined bicuspid extraction spaces on the distal, and several teeth were restored. We corrected lateral dis- placed retrognathic mandibular position and by doing the develop the comprehensive treatment planning for this patient, highly good treatment results based on treatment goal can be obtained. Discussion: According to jaw movement measuring, we determined the therapeutic mandibular position to grope for ideal man- dibular position, and fabricated occlusal appliance. We indicated to wear the occlusal appliance for ３ weeks, and then re-evalu- ated the jaw movement. We decided the ideal mandibular position, and by doing the comprehensive treatment, resulting in a favorable outcome. Conclusion: We have to develop the realistic treatment planning, before we treat the patient. In complicated situations, you must think carefully, develop a well-ordered treatment plan, identify each complex element step by step, and eliminate the cause of failure.

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Patient: The patient was a 41-year-old female. The chief complaints were swelling of mandibular molar area, mastication pain and occlusal pain. She had moderate to severe periodontitis. Anterior guidance was absent due to open bite of the anterior teeth, and there was localized periodontal progression of the posterior molars. After thorough periodontal treatment, implant therapy, and orthodontic treatment, the treatment result was stable. Discussion: There is no evidence that excessive occlusal force, mainly due to bruxism, is a modifying (exacerbating) factor in the progression of periodontitis. However, there are many clinical cases in which this involvement is suspected. In order to clarify the involvement of force, it is necessary to screen for the risk of force mainly through occlusal examination. If the results show a high risk of force, force control including occlusal treatment is necessary. Result: For patients with moderate to severe periodontal disease, force control based on force risk diagnosis as well as inflamma- tion control is important.

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Patient：The determination of occlusal vertical dimension （OVD） is ultimately evaluated in the oral cavity because the oral cavity is more delicate due to the density of various sensory receptors． Most of the techniques for determining （OVD） are based on soft tissue references that lead to measurement discrepancies． Therefore， in recent years， the use of cephalometric analysis has been recommended． The analysis of Ricketts， which is a method for determining the OVD using LFH， is based on the maxillary standard in all the evaluation methods． In other words， the position of the Xi point that constitutes the reference point of LFH does not change in the mandibular body， but when the horizontal mandibular position changes， the position changes from the maxillary reference． Most of the decrease in OVD is not present on a simple axis of rotation， resulting in both horizontal and vertical changes． This time， we report a case in which the OVD was determined in the oral cavity using an overlay after establishing an index considering the type of facial of the patient and the change in the horizontal mandibular position using the cephalometric analysis． Discussion：The facial pattern of the maxillofacial region depends on the occlusal force during the growth period is suggested． In addition， since the OVD affects muscle activity if it is raised too much， it is desirable to use the lift amount according to the skeletal pattern as a guide． As can be seen from the Gonial Angle， it was presumed that this case had a brakyo facial pattern even before the past orthodontic treatment． However， the analysis result at the first visit was a severe brakyo facial pattern． Therefore， we applied the formula of Yamashita et al． To the index for determining the OVD and set a target． The result of this formula is that LFH 37．25 ° is desirable． Since the LFH was 33 ° at the first visit， it was judged that it was possible to raise the patient， and finally， we proceeded while confirming the comfortable condition with re-orthodontic treatment， occlusal device， overlay restoration， etc． As a result， although it was a coincidence， the LFH was 37 °， which was close to the target．

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Patients: Patient is a 25-year-old female．She was referred by her orthodontist．During orthodontic treatment，the patient requested esthetic improvement for discoloration of her maxillary anterior teeth and metal restoration of her molars． The orthodontist referred the patient to our clinic because it was deemed necessary to consult with a prosthodontist before completing orthodontic treatment． We consulted with the orthodontist on the approach of prosthetic treatment after orthodontic treatment，and we set common treatment goals for the orthodontic treatment． After the orthodontic treatment，we re-evaluated the patient and identified the functional and esthetic problems that could not be improved by orthodontic treatment，and improved them by prosthetic treatment．The treatment results were satisfactory to the patient． Discussion: The orthodontic treatment and improvement of tooth position allowed restorative treatment of the anterior and molar teeth with minimal intervention．As a outcome，the pulp was less affected and the enamel was preserved as much as possible，thus maintaining the strength of the tooth and the predictability of the tooth and the prosthetic device． Conclusion: The present case is important that a close interdisciplinary approach between orthodontist and prosthodontist for the success of prosthetic treatment，even in the middle of orthodontic treatment，since orthodontic treatment is available for a wide range of age groups.

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Patients: Comprehensive orthodontic treatment allows you to develop a treatment plan that closes the defect space or the space extracted due to poor prognosis dentitions. The occlusal relationship with the treatment goal is one of the molar relationships, class I, class II, and III. The purpose is to plan for proper canine-related, anterior overjet, and overbite. At the same time, an orthodontic aesthetic diag- nosis is performed and a comprehensive treatment plan is formulated. Plan the position of the target anterior teeth and, develop a treatment plan that sets the position and relationships of the molars that can be achieved. We report a case in which a patient with a missing dentition was first diagnosed with orthodontics and obtained good treatment results. Discussion: Examined how to formulate a treatment plan to determine the position of the molars that can achieve the set ante- rior tooth position. In Case １, As a treatment plan for mandibular incisor defects, we believe that the defect site was extracted for convenience instead of the premolar for convenience. In the mandible, the canine has something in common with the root mor- phology and crown morphology of the premolar, so it is possible to substitute the first premolar as the canine. In Case ２ ，As a treatment plan for left and right mandibular molars and maxillary right premolar defects, if the premolars on the left side of the maxilla are extracted, the molar relationship becomes class II (full class II).From premolars to canines, there is an ideal class I relationship. In case ３, As a treatment plan for maxillary bilateral molar defects, if the mandibular bilateral premolars are extracted, the molar relationship becomes class III (full class III). From premolars to canines, there is an ideal class I relationship. Result: An orthodontic aesthetic diagnosis is performed to determine the position of the molars that can achieve the set anterior tooth position, it is possible to obtain proper anterior tooth contact that enables functional exercise.

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Purpose：Introduction of a new telementoring system for live instruction on clinical procedure. Materials and Methods：Stereo viewer was used for monitor of 3D digital microscope. In telementoring system, surgical field dis- played on a stereo viewer was connected remote dental instructor through the internet. Discussion：Periodontal surgery was performed using a new telementoring system. Four conditions were considered essential in telementoring for dentistry. 1 ) low latency, 2 ) high quality 3D video, 3 ) reference point on the surgical field（line, cursor et al）, 4 ) high security. Conclusion: Op

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Purpose：Providing a technical note to the effective use of dental adhesive systems． Materials and Methods：Direct composite resin restorations were performed using a two-step adhesive system including a self-etching primer capable of both etching and priming． Discussion：The two-step self-etching primer system with functional monomers avoided over-demineralization of dentin． However，in order to apply the system effectively，it is necessary to pay attention to various points，such as removal of infected dentin，adhesive treatment with long-term stability，incremental filling，light irradiation，and morphological modifi- cation and polishing． Conclusion：Modern dental adhesive systems，when properly understood and applied，have excellent capabilities．

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