The concept of the biomimetic approach to restorative dentistry is currently widespread, and adhesive restorations that preserve enamel and tooth structure as much as possible are becoming a worldwide phenomenon. With the advance of adhesive technology and the availability of implants, an aggressive tooth preparation for crown and bridge restorations to provide conventional retention and resistance forms should now be used only for re-treatment of crowns and bridges for both anterior and posterior teeth. Since it is difficult to regenerate the hard tissues of teeth at this stage, the objective of restorative treatment is to minimize treatment invasion, preserve the remaining tooth structure and tissues, and maximize the specific advantages of natural teeth to approximate and reproduce the biological, structural, mechanical, functional, and esthetic properties of the natural teeth. The tooth preparation design of posterior veneer restorations should be derived on an individual case basis from the following aspects: 1) remaining tooth structure and surface coverage, 2) bond quality, 3) biomechanics, 4) tooth flexure control, 5) maintenance of the bonding interface, 6) material selection, 7) thickness of restoration, and so on. In this review, we will discuss the recommended basic preparation designs for occlusal veneer restoration from both evidence and experience perspectives, including reference searches. In addition, there are few reports of systematic classification of veneer designs, especially for posterior teeth. Therefore, we would like to propose a systematic classification of occlusal veneers based on the preservation of enamel.

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Purpose：It has been reported that many patients with mandibular lateral deviation have occlusal system changes and temporo­mandibular joint symptoms. Patients with mandibular lateral deviation often have problems such as a discrepancy in the proxi­mal-central molar relationship, buccolingual molar axis difference in the frontal plane, and molar crossbite, and it is one of the most difficult cases to establish a functional satisfactory occlusion. In this study, we investigated the relationship between man­dibular lateral deviation, disk shift, and inclination of the occlusal plane in patients with asymmetrical lower faces in the occlusal head-fitting position. Methods：The same dentist analyzed intraoral photographs and standard frontal head X-ray photographs taken with the same equipment. The patient was diagnosed by one radiologist as having a displaced articular disk based on the MRI. The correlation coefficients between the degree of mandibular lateral deviation and occlusal and skeletal variables were calculated. Results：The occlusal plane and mandibular submarginal plane were located higher on the deviated side, and there was a strong correlation between the degree of mandibular deviation and the occlusal plane angle (ρ =0.684, p<0.001) and mandibular sub­marginal plane angle (ρ =0.714, p<0.001), respectively. The results showed a strong correlation between the mandibular lateral deviation and the mandibular angle. In addition, 81.7% of the patients with lateral mandibular deviation showed a displaced articular disk. Furthermore, the highest percentage (61.7%) of patients had bilateral disk dislocation on the deviated and un-devi­ated sides, and 35% of patients with lateral mandibular deviation and 25% of patients with mandibular deviation had TMJ osteoarthritis. Conclusion：Most of the patients with lateral mandibular deviation had a displaced articular disk and an inclined occlusal plane. The results suggest that there is a solid relationship between lateral mandibular deviation and the inclination of the occlusal plane.

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Objective：To investigate the usefulness of quantitative evaluation of tongue position in predicting the efficacy of oral appliance（OA） treatment for obstructive sleep apnea （OSA）．Methods：Patients （male and female） aged 20 years or older with an apnea-hypopnea index （AHI） of 10 or higher who were diagnosed with OSA at a collaborating medical institution and who visited our clinic and selected OA therapy were included．In this study，the preoperative period was defined as the period from the polysomnography （PSG） test at the time of diagnosis of OSA to the start of OA use，and the postoperative period was defined as the period from 3 to 6 months after the start of OA use，when it was determined that continuous use of OA during sleep was possible，and when a PSG test to evaluate the effect of OA was performed．The PSG recordings made before and after surgery，Body Mass Index （BMI） and Epworth sleepiness scale（ESS） measured immediately before the PSG examination，and standardized lateral head X-ray photographs（cephalogram） taken preoperatively were analyzed．The distance from the plane of the palate to the intersection of the tongue surface and a vertical line that runs from the plane of the palate through the centric edge of the maxillary first molar （T-PL） was measured as an index of lingual position．The postoperative PSG results were used to evaluate the AHI．The postoperative PSG records were classified as responders if the AHI was less than 5 ，and non-responders if the AHI was greater than 5 ．The comparison between the two groups was performed using the student t-test （ p<0.05） for normally distributed variables and the Mann-Whitney U test （ p<0.05） for non-normally distributed variables．For pre- and postoperative comparisons within each group，a paired t-test was used for normally distributed variables，and a Wilcoxon signed-rank test was used for non-normally distributed variables．Logistic regression analysis was used to determine predictors of treatment effect in OA．Results：The 80 OSA patients （68 men and 12 women） included in this study were classified as mild （n = 24），moderate （n =３６），or severe （n = 20）．The mean preoperative age was 46.6 ± 12.5 years，mean BMI was 24.0 ± 3.2 kg/m 2 ，median AHI was 19.2 （14.1-30.5） times/hour，and mean ESS was 11.0 ± 5.4．There were significant differences in preoperative BMI，AHI，REM phase AHI，non-REM phase AHI，and lower facial height （LFH） on lateral head radiographs between the responders （３３ patients） and non-responders （47 patients） groups （ p<0.05）．There was no significant difference between the two groups in T-PL，which was used to evaluate tongue position．Pre- and postoperative comparisons between subjects in each group showed that OA significantly decreased AHI，REM phase AHI，and non-REM phase AHI （ p<0.01） and significantly increased minimum SpO 2 （ p<0.01）．Logistic regression analysis showed significant differences in preoperative AHI，BMI and LFH，which were significant predictors of OA treatment efficacy （ p<0.05）．Conclusion：In this study，we evaluated the relationship between various endpoints，including quantitative evaluation of tongue position on cephalogram taken before OA treatment，and the treatment effect of OA．The results suggest that LFH may be a predictor of OA treatment efficacy，while T-PL，which is used to evaluate tongue position prior to OA treatment，cannot be used as a predictor of OA treatment efficacy．There is no COI relationship to disclose in this study．

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目的：ステージⅢ・Ⅳの歯周炎で手術用顕微鏡を使用した低侵襲非外科治療とEr:YAGレーザー併用の有用性を検討すること． 方法：2019年11月から2022年 ３ 月までに本手法で治療した20歳以上の歯周病患者治療前後の臨床的・エックス線的パラメータを 後ろ向き調査し，臨床的アタッチメントレベル獲得量≧ ３ mmかつ術後 probing pocket depth（PPD）≦ ４ mmの達成要因を探索 した． 結果：治療後各種パラメータは歯根形態や部位を問わず有意に改善し， ８ mm ≦術前 PPD ≦10mmおよび術前垂直性骨欠損量≦ ４ mmにおいて治療達成確率が高まった． 結論：本手法のステージⅢ・Ⅳの歯周炎に対する有用性，適応目安の術前 PPDおよび垂直性骨欠損量が示された．

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Purpose: This study aimed to investigate variations in the amount of Porphyromonas gingivalis (P. gingivalis) over time after dental implant prosthetic treatment using a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Methods: From October 2020 to April 2022, samples were obtained from the natural teeth and dental implants to evaluate the bacterial amount (P. gingivalis and P. gingivalis Type Ⅱ) using orcoa®, a semi-quantitative RT-PCR-based device developed to detect oral bacteria, at three timepoints (prior to dental implant prosthesis, one month after prosthesis, and six months after prosthesis). Additionally, participants' demographic data were collected. Result: This survey included 20 consecutive patients treated with dental implants (9 [45.0 %] men and 11 [55.0 %] women), with a median age of 62.0 years (interquartile range, 50.0–74.0 years). With regard to the natural teeth, significant differences in P. gingivalis amount in the gingival pocket were observed between the high and low groups at all timepoints (P <0.05). In contrast, no significant differences in P. gingivalis amount in the gingival pockets around dental implants were observed between the groups over time. Conclusion: In patients with well-maintained oral care, the amount of P. gingivalis could not increase in the pocket of dental implant treatment within 6 months after the prosthesis. The growth of P. gingivalis in the gingival pocket is dissimilar and its kinetics differ between the natural teeth and dental implants.

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目的：歯周炎ならびにインプラント周囲炎の予防は患者のセルフケアに大きく依存している．本研究の目的は，口腔内細菌に対 する洗口液の増殖抑制効果を評価することである． 方法：インプラント治療のメインテナンス中の患者30名を対象とし，細菌数の計測と各種細菌の定量化を行った． 結果：洗口液の １ 週間の継続使用により，口腔内細菌数が有意に減少した．定量的 PCR 法により，インプラント周囲炎に関連す る細菌６ 菌種の細菌数の減少を認め，そのうち２ 菌種に統計学的有意な差を認めた． 結論：本研究において，洗口液の連続使用が口腔内細菌数を減少させ，口腔内細菌の増殖を抑制する効果があることが示唆された．

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Purpose：To propose a classification of pontic according to the contact relationship between the basal surface of the pontic and the alveolar ridge of the defect. Materials and Methods：The pontic was classified into three types： 1 ； Naturally fit type pontic, 2 ； Pressured gingival type pontic, and 3 ； Modified gingival type pontic, and the characteristics of each type were examined. Discussion：Naturally fit type pontic is a type of pontic with a pontic basal surface in contact with the intact alveolar ridge of the defect and is indicated for cases without strong esthetic, functional, or hygienic requirements. The pressured gingival type pontic has a convex pontic base surface and is in pressurized contact with the soft tissue of the alveolar ridge to improve esthetics and cleanability. The modified gingival type pontic is indicated when esthetics are strongly desired, and the soft tissue is aggressively formed and the base of the pontic is in deeper contact with the alveolar ridge of the defect. Conclusion：The contact between the base of the pontic and the soft tissue of the missing alveolar ridge is more important than its morphology, and its use depends on the condition of the missing alveolar ridge and the degree of esthetic, functional and hygienic requirements.

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Patients：The patient is a 40-year-old male. His chief complaint is esthetic improvement due to anterior crowding. He had been dissatisfied with the plexus of his maxillary and maxillary anterior teeth for a long time and was suspected to have clenching due to heavy stain deposition from smoking and occlusal wear on the molar surfaces. Other intraoral findings revealed a history of acid erosion due to food (dried plums and soda), reflux esophagitis, and abrasion (brushing), as well as parenchymal defects in the buccolingual cervical region of the molars due to physical and chemical factors. Preoperatively, the patient was diagnosed as a mild skeletal class Ⅲ patient with crowded anterior teeth , and was treated with a combination of orthodontic and prosthetic treatment based on a comprehensive treatment plan. As a result, the patient's chief complaint was improved and the treatment result was in accordance with the target. Discussion: In the treatment of adult patients with skeletal Class III disease, it is necessary to first diagnose whether orthodontic treatment alone or in combination with surgery should be performed after basic periodontal treatment. Valko et al 1 considered an ANB angle of - 2 ° or less as an indication for orthodontic treatment. In the present case, the ANB angle was 0 ° and the patient was a mild skeletal Class III patient, so a nonsurgical treatment method was adopted. The treatment plan includes a slightly steeper occlusal plane to prevent forward movement of the mandible, and a treatment method to rotate the mandible in a clockwise direction by raising the occlusal height, and to move the opposition of the upper and lower jaws in the sagittal plane from Class III to Class I2. Based on the above treatment plan, the first step is to determine the direction of the mandible. Based on the above treatment plan, orthodontic treatment was firstly performed to improve the plexus of the upper and lower anterior teeth, left lateral crossbite, tooth position, and to control the occlusal plane. In addition, the patient's maxillary anterior teeth were worn down due to incisal occlusion, making it difficult to provide appropriate anterior crown and anterior guidance, and the occlusal surfaces of the molars were also worn down. To solve these problems, we considered it necessary to restore the crown morphology by full prosthodontic treatment after orthodontic treatment. Conclusions: Comprehensive dental treatment combining orthodontic and prosthetic treatment was performed on a mildly skel- etal Class III patient with problems in dentition and tooth morphology. As a result, by changing the mandibular position, occlusal plane, and occlusal height diameter, the mandibular anterior crown and molar occlusal support were established, and esthetic and functional improvement was achieved. Careful follow-up is necessary to maintain and stabilize the mandibular position, periodontal tissues, and prosthetic appliances.

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The patient is a 54-year-old male. He presented with a complaint of swelling of the maxillary right central incisor with move- ment. Since it the tooth could not be treated with a abutment tooth, it was planned to replace with an implant. The patient had esthetic and functional problems mainly in the anterior maxillary region other than the main complaint, and we decided to perform a full-maxillary treatment intervention to improve these problems. After some clinical thresholds were assessed including facial appearance and posttreatment alteration of gingival level, periodontal plastic surgery, implant treatment and orthodontic treatment were performed and final restorations could satisfy the patient. Discussion: By setting the final treatment goal including the reestablishment of the gingival level of the maxillary anterior teeth, the three-dimensional implant placement position was determined in consideration of the final gingival level and bio- logical stability, and surgical crown lengthening was performed on the remaining teeth to obtain esthetics and ferrule. By considering the treatment plan from the final treatment goal, the surgical treatment was efficient and minimally invasive, and good esthetic and functional results were obtained. Conclusion: The three-dimensional implant placement site, which is derived from the treatment goal, can only be pinpointed. Therefore, it is necessary to examine not only the condition of the periodontal tissues but also the face and mouth, and to for- mulate and carry out an appropriate treatment plan.

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