Laws and guidelines relating to ethics are now being issued by the government nearly every year. Not only do dental professionals conducting clinical research have to comply with an increasing number of regulations ; they must first gather a large amount of information to store as knowledge. Since the scope of application of the “Ethics Guidelines for Epidemiological Research” (revised in 2007) and the “Ethical Guidelines for Clinical Research” (revised in 2008)─both issued by the Ministry of Health, Labour and Welfare and the Ministry of Education, Culture, Sports, Science and Technology─was considered difficult to interpret, the guidelines were integrated into the “Ethical Guidelines for Medical and Health Research Involving Human Subjects,” which have been in effect since 2015. Following their enforcement, with the recent full-fledged implementation of the updated Act on the Protection of Personal Information, which clarifies the scope of personal information and provides for its legitimate distribution, these guidelines have also been revised to ensure proper handling of personal information in research, and came into effect on May 30, 2017. In recent years, several such new or revised ethical laws and guidelines have been implemented. Obviously, non-compliance is not an option, so a realistic outlook of the facts is necessary to prevent researchers from abandoning research in dejection. It is therefore essential to grasp the background of the strengthened regulations and understand their purpose and requirements. An ethics training conference known as the “Ethics Committee Seminar,” hosted by the Japanese Society of Oral Implantology, was relaunched as the “Ethics Seminar on Medical Research” in response to the overwhelmingly rapid revision of guidelines and to attempt to disseminate information. In addition to imparting an understanding of the original ethical guidelines, the announced purpose of this seminar is to explain what kind of research requires an ethics review in this academic society and, for research and case reports that require it, how to apply to the ethics review committee. However, because of the large number of members, it is difficult to provide ethics review training to everyone. Since members still perceive a lack of clarity in ethics applications, this article explains the essence of medical ethics and provides commentary on details of the latest amendments in ethics regulations, as well as ways of creating research ethics applications to help members understand what kind of academic research requires an ethics review.

To ensure that patients are satisfied with the esthetic outcomes of implant treatment, it is not only essential to restore the crown of the tooth but also to ensure that the peripheral gingiva and interdental papillae are well positioned for long-term stability. To achieve these goals, it is important to secure sufficient bone (hard tissue) and soft tissue at the implant site. Although there are individual differences, it is generally accepted that if the implant and abutment have the same diameter, at least 2 mm of bone must be secured on the buccolingual (labiopalatine) side of the implant, or at least 1.5 mm in the case of platform switching, with at least 1.5 mm between the implant and natural teeth and at least 3 mm between two implants, depending on the design that is used. As it is thought that peri-implant soft tissue must be around 4 mm in height, many authorities suggest that if the implant and abutment have the same diameter the implant insertion depth must be around 3 mm deeper than the peripheral gingiva in the apical direction, and around 4 mm deeper if platform switching is used. The required thickness of buccolingual (labiopalatine) soft tissue is believed to be around 2 mm. The shape of the superstructure is concave below the gingival margin to secure the required thickness of buccolingual (labiopalatine) soft tissue, and the halfpontic technique can be used for the abutment shape using the same method as for tooth restoration. If insufficient tissue is present, it must be augmented ; however, in consideration of long-term esthetic prognosis, a slowly resorbable or nonresorbable bone substitute should be used for bone augmentation, while for soft tissues autologous grafts maintain augmentation over the long term.

Recently the criteria for success include esthetic satisfaction for patients and practitioners but it is not easy to achieve optimal esthetics in the esthetic zone in cases with multiple implants. This article discusses the conditions for long-term esthetic success. Among such conditions, the first step is setting realistic goals which are shared by both patient and practitioner. If the patient has a high smile, surgical reconstruction of the esthetic soft tissue framework will be necessary and the practitioner should understand the necessary procedures for hard and soft tissue management indicated by the pre established surgical template. If the patient's smile is low, the soft tissue architecture can be achieved prosthetically. Additionally, it is reported that 90 percent of low-smile patients still show the tip of the papilla, and an esthetic papilla tip plays a very important role in achieving a natural-looking smile.

Considering tissue management, partial extraction therapy is an effective tissue preservation procedure. When the tissue is lost, guided bone regeneration can augment the alveolar bone to satisfy the three-dimensional requirements for esthetics. Soft tissue management will inevitably be necessary to maintain regenerated bone and to acquire enough soft tissue volume and quality to be esthetically remodeled with a prosthesis. In addition, soft tissue management can be used to solve the potential problems which can occur in the maintenance period. For long-term esthetic success, practitioners must execute every treatment procedure as precisely as possible and establish a meticulous maintenance program.

To obtain a satisfactory outcome with implant treatment in the anterior esthetic zone, first, examination of the preoperative countenance and smile line position, examination of hard and soft tissue, and diagnosis of defective alveolar ridge or extraction site are needed, followed by the creation of a placement plan for appropriate 3D positioning of the implant including patient biotype, extraction timing, implantation angle and depth, as well as surgical considerations such as creating an environment with sufficient volume including the reconstruction of peri-implant hard and soft tissue. Additionally, remarkable progress has been made in various digital devices used in the protocol from implant placement planning to actual placement. 3D examination of the treatment plan associated with determining implant position, fabricating guides using intraoperative implant position confirmed by diagnosis, and so-called guided surgery has further increased in accuracy with digital technology and has been clinically applied. Particularly with the development of intraoral scanners, techniques for performing surgical procedures by digital guided surgery using digital intraoral scan data and CBCT data are advancing, and are effective for modern implant treatment.

Dental CT was developed in the late 1990s to enable three-dimensional imaging. Today, it has become an indispensable diagnostic imaging device for dental care, including dental implants. In addition, a wide variety of models have been developed, and it has become possible to select FOV and voxels of various sizes. However, as the exposure dose is about 10 times as high as intraoral radiography and panoramic radiography, attention must be paid to its application. In accordance with the principles of ALARA, it is necessary to carry out efficient diagnostic imaging to achieve diagnostic objectives with the lowest possible exposure dose. This paper introduces the points to keep in mind and the latest trends in imaging equipment.

Digital dental, panoramic, and CT images may show bone resorption such as pseudo bone defects caused by digital artifacts, making it difficult to evaluate integration.

CBCT images, which enable the three-dimensional structure to be grasped and which seem to be accurate, are not the standard photography, and the implants shrink in all directions of X-ray incidence. Similarly, the distance between multiple implants shrinks and the positional relationship of the implants shifts. As a result, there are problems in accuracy and reproducibility which affect digital dentistry (digital matching, CAD-CAM, simulation). Thus, careful attention is needed for measuring distance, evaluating the dimensional chronological change of bone around the implants, and evaluating osseointegration. On the other hand, by correcting the shrinkage, implant treatment may be possible even in diagnostically unsuitable cases.

Shrinkage and bone resorption in digital images are demonstrated. Examination and diagnosis by considering digital data shrinkage and the clinical problems of CT images in implant treatment are also discussed.

Objectives : With the aim of improving the stability of implant prostheses, the clinical course after placement of singlestanding implants in the mandibular molar region was compared between screw-retained and cement-retained implants.

Subjects and methods : The subjects were a total of 71 implants placed in 55 patients in the clinic where the first author practices. Patients were followed up to compare the incidence rates of peri-implant mucositis, peri-implantitis, and other complications between screw-retained and cement-retained implants.

Results : Single-standing implants were stable (success rate : 98.6%). Incidence rates of peri-implant mucositis and periimplantitis did not differ significantly between screw-retained and cement-retained implants, at 17.2% (5/29) and 31.0% (13/42), respectively, for peri-implant mucositis and 3.4% (1/29) and 7.1% (3/42), respectively, for peri-implantitis. Furthermore, there were no significant differences in all investigation items between screw-retained and cement-retained implants.

Discussion and conclusion : There were no significant differences in the prevalence of peri-implant mucositis and periimplantitis between screw-retained and cement-retained implants. The findings of this study highlight the importance of choosing a fixation method based on specific advantages and disadvantages in individual cases.

Polyetherketoneketone (PEKK) is expected to be applied to abutments and implant superstructures, since it has been shown to act as a shock absorber and reduce the pressure on the implant body during chewing. PEKK has a chemically stable structure, and it is known to be difficult to bond the resin cement chemically. In this study, the effects of various bonding systems on the bonding strength of PEKK and resin cement were investigated using rocatec treatment and sandblasting treatment, which are simple surface treatment methods.

This study used various bonding systems : Superbond/V primer bonding system (SB/VP), Superbond/PZ primer bonding system (SB/PZP), Panavia V5/Clearfil Ceramic Primer Plus bonding system (PV5/CP), and glass ionomer cement (GI). The PEKK polished surface was subjected to rocatec treatment or sandblasting treatment. Thereafter, the primer of the bonding system was allowed to act for the predetermined time according to the manufacturer's instruction, and then resin cement was filled and polymerized to prepare PEKK bonding specimens. Next, the shear bond strength was measured with the universal tester for PEKK bonding specimens. PEKK specimens were observed by scanning electron microscope (SEM), and the surface roughness of the PEEK surface treated by rocatec or sandblasting was measured.

As a result, the bonding strength of the PEKK surface subjected to rocatec or sandblasting treatment was improved in all the bonding systems. However, the rocatec treatment showed significantly lower values than the sandblasting treatment, and many adhesion defects were observed by SEM. The maximum bond strength was attained when the PEKK surface was treated by sandblasting and SB/PZP was applied. On the other hand, there was no significant difference in the surface roughness between rocatec and sandblasting treatment.

From the above, it was considered that when rocatec was applied to the PEKK surface, the silica coating layer that formed on the PEKK surface acted as a peeling layer, and therefore the bonding strength was lower than with sandblasting treatment. In addition, the bonding strength showed different values for each bonding system.

One of the risk factors of implant treatment is patients with diabetes mellitus, as it is difficult to acquire osseointegration compared with healthy patients. There are time-related changes to the titanium surface, and the cell affinity and histocompatibility of the titanium decreases. Ultraviolet (UV) treatment to titanium is known to effectively improve these changes. Therefore, in this study, we investigated whether implant treatment for diabetic patients could be enhanced by UVtreating titanium surfaces cultured with bone marrow-derived osteoblast-like cells of type 2 diabetic rats (Spontaneously Diabetic Torii : SDT). These cells were cultured in a low glucose environment similar to the state in which the blood glucose level was controlled.

The experiment was divided into two groups : 1) The control group in which osteoblast-like cells of SDT rats were placed on control discs and 2) the UV group in which osteoblast-like cells of SDT rats were placed on UV-treated discs. In this study, these osteoblastic cells were derived from SDT rat bone marrow which was cultured in a low glucose environment, and placed onto both the control and UV treated discs. The control discs were used 4 weeks after surface acid-etching treatment. The UV-treated discs were subjected to 48 hours of UV irradiation. In addition, WST-1 Cell Counting Kit, alkaline phosphatase (ALP) activity and Alizarin red staining were used to evaluate t he number of attached cells, differentiation, and mineralization, respectively.

In the UV group, the number of attached cells was small compared with the control group. The ALP activity of the UV group was higher than that of the control group. Furthermore, calcification activity of the UV group was higher than that of the control group.

Collectively, our data suggest that the osteoblast-like cells of SDT rats on the UV-treated discs enhanced differentiation to osteoblasts. It is considered that UV treatment of titanium is a useful method for implant treatment of diabetic patients. However, further study is required to examine the differentiation of osteoblasts and expression of bone formation related genes in a high glucose environment, in addition to further in vivo research of implants for diabetic rats.

Bone augmentation of the maxillary sinus is commonly required due to resorption of the alveolar crest before implant treatment for maxillary molar defects. Maxillary sinus floor elevation performed using a lateral window technique sometimes necessitates the creation of a bone window in the anterior wall of the maxillary sinus, although care is required with regard to the blood vessels present in the anterior wall to create the bone window safely.

We developed a method that allows observation of blood vessels that are located within the area where the bony window will be created. In this paper, we summarize a case managed using this method and details of the surgery. We created a diagnostic stent for use during preoperative planning, and used simulation software to plan the implant insertion. When we confirmed the position of the bone window, we observed blood vessels running along the anterior wall and floor of the maxillary sinus. In order to confirm the position of the blood vessels, we created a bone model of the maxilla using a 3D printer, and simulated the creation of the bone window on the model. Maxillary sinus floor elevation was then performed based on the preoperative planning. There were no complications, such as abnormal hemorrhage, during or after surgery, and the clinical course was favorable. We did not observe marked bone resorption around the implant two years after we mounted the final superstructure, and plaque was well controlled.

We encountered a case in which blood vessels ran through the area where the bone window would be located in the anterior wall during maxillary sinus floor elevation using a lateral window technique. By performing a preoperative simulation using a bone model created with a 3D printer as part of preoperative planning and using computed tomography (CT) as a form of diagnostic imaging, we were able to detect the position of the blood vessels in advance. This enabled us to gain a comprehensive understanding of the position of the blood vessels, which enabled us to minimize blood vessel injury intraoperatively.

Purpose : Dentists and dental hygienists are experts of oral hygiene management, and it is likely that their dental and peri odontal states are better than those of general people. We hypothesized that there would be a low risk of losing teeth due to periodontal disease if the whole population performed the same self-care method as dentists and dental hygienists, and inves tigated the dental and periodontal states of dentists and dental hygienists.

Materials and Methods : We mailed a questionnaire to 130 dental clinics affiliated with the Fukuoka Oral Implant Research Association and engaging in oral implant treatments and asked the dentists and dental hygienists to participate in the investi gation and fill out the questionnaire, which included questions on systemic and dental anamnesis, lifestyle, intraoral state, and oral hygiene management method.

Results : The number of subjects that filled out the questionnaire was 225 (43 facilities). The average age of the subjects was 38.9 years old, and the sex ratio was 22.7% men and 77.3% women. The average number of tooth-brushing times per day was 3.0 ; the mean number of present teeth was 27.3 ; the ratio having probing depth of more than 4 mm was 6.1% ; the ratio with bleeding at the time of probing was 12.1% ; and the number of DMFs was 8.9. The total number of missing teeth of all subjects was 179, of which 66 sites were restored by some kind of prostheses (31 sites by dental implants, 15 by bridg es, 1 by removable denture, 19 sites unclear).

Discussion and Conclusion : The intraoral state of the subjects revealed that their condition was generally good, but pre dicting the future results of subjects from a lower age group would be difficult. We will collect data for dentists and dental hygienists of an older age group, and aim to develop a self-care method to achieve the 8020 campaign in future.