Implant treatment plays an important role in the recovery of defects, and also in improving oral functions. The Japanese Society of Oral Implantology (JSOI) believes that collaboration with related academic societies of other countries is indispensable for providing safe and secure implant treatment and correct information to the general public. In this article, we report on the situation at the German Implant Society and the Thai Implant Society, which have an agreement with JSOI, and the Indonesian Implant Society, which is seeking cooperation in the future. We also introduce the implant specialist systems in these countries.

Implant therapy has reached its present state after overcoming many challenges. The target of implant treatment is missing teeth, ranging from one missing tooth to an edentulous jaw. Naturally, residual teeth are also included in the treatment. Therefore, most implant-treated patients have various pathological conditions. Furthermore, the desires of patients are diverse, even if only one tooth is missing. In 2002, Watanabe et al. analyzed the clinical application of 271 cases, 792 IMZ implants performed over the past 13 years at two facilities, a university hospital and an individual dental clinic, and examined the implant patients, cumulative survival rate, and upper and lower jaws. The cumulative survival rate of the IMZ implants was evaluated by comparing the cumulative survival rates by implant body size, and the cumulative survival rates at both institutions were 96.3% at 5 years, 92.6% at 10 years, and 89.9% at 13 years. In recent years, Japan has become a super-aged society with the longest life expectancy in the world. This involves the aspects of both improving QOL and extending healthy life expectancy, but the future of implant treatment in this long-lived society is a major issue.

Periodontal disease is a multifactorial chronic bacterial infectious disease of the plaque, which is caused by a complex combination of periodontal pathogen, host, environmental, and occlusal factors. Given that the risk factors for periodontal disease are the same as those for implants, intervention is important during implantation to permit more appropriate control of an eventual periodontal disease.

Patients with severe periodontal disease, such as generalized severe chronic periodontitis and generalized aggressive periodontitis, have a poor dental prognosis. The presence of poor tooth prognosis and a decrease in the amount of residual periodontal tissue often make it difficult to choose a treatment plan. In addition to the prognostic value of each tooth, the prognostic value of each patient must be appropriately determined. In particular, the choice of whether or not to preserve or extract the tooth, or whether or not to sharpen and fix it, is a challenge that rests on the discretion of each individual surgeon. In recent years, good prognosis and longevity of dental implant treatment have been established, and it is now possible to use implants with strategic extraction to improve the quality of treatment. Herbal treatment is increasingly used in many cases. However, it is also true that nothing is better than a tooth with a periodontal ligament, and the main goal of dentists is to preserve the tooth for as long as possible.

In this paper, we present the following cases : a bone-anchored bridge after strategic extraction, teeth preservation and replacement with periodontal prostheses, and the preservation of as many teeth as possible with implantations for the missing parts. We also discuss the significance of tooth preservation.

Recently, dental implants are widely used clinically as one of the options for prostheses in edentulous spaces. Currently, most implant experts take osseointegration for granted, and the focus is shifting to obtaining esthetic recovery. Therefore, the topic of soft tissue augmentation surrounding dental implants is steadily attracting interest.

The augmentation of soft tissue around implants started in the late 1990s with free gingival grafts to sites where there was insufficient keratinized gingiva, such as transplantation of connective tissue to the labial side, and many researchers started to announce various clinical cases since 2000, with many reports now appearing. In everyday clinical practice as well, soft tissue augmentation procedures are being performed at various stages of treatment in order to improve the predictability and es thetics of implants. From an esthetic point of view, harmony between the hard and soft tissues surrounding the implant is important for the esthetic result. In order to minimize biological complications in future, soft tissues around the implant are also important.

This paper examines the effectiveness of soft tissue augmentation for tissues surrounding the implant, with a review of the literature.

To prevent recession of the marginal soft tissue after installation of the implant superstructure, a hard tissue thickness of 2 mm or more is required on the buccal (cheek) side of the implant. Therefore, if the remaining bone lacks thickness, some hard tissue augmentation is required.

Conventionally, block bone grafting has been recommended for highly atrophied ridges. However, adaptation of the block bone to the recipient site, the surface morphology of which is usually irregular and complex, is problematic. This can lead to poor prognosis of the engraftment.

Under these circumstances, Dr. Urban introduced “a sausage technique”, in which a bone graft composed of a mixture of granular autogenous bone and slow-resorbing xenogenous bone (deproteinized bovine bone mineral) is covered and immobilized at the recipient site with a resorbable collagenous membrane that is secured using fixation pins. This technique allows high adaptability of the graft to the recipient site as it uses granular bone, and is relatively safe because it uses a resorbable membrane with a low wound dehiscence rate.

However, large bone resorption, especially on the buccal (cheek) side of the alveolar ridge shoulder where the external pressure is markedly concentrated, is a major drawback and often requires additional GBR during implant placement. Moreover, the space-making capacity in the vertical direction is relatively poor.

Therefore, in cases where a vertical and even horizontal hard tissue augmentation at the alveolar ridge shoulder is desired, a titanium-reinforced non-resorbable membrane is preferable.

Vertical bone and soft tissue augmentation in multiple missing teeth are the most difficult procedures in implant treatment. Making the diagnosis and deciding the treatment goal before surgery are important for improving the predictability. In general, the goal of bone augmentation in non-esthetic areas such as the posterior region is to ensure the bone volume needed for function by an implant-supported prosthesis. The goal of soft tissue augmentation is to improve the cleanability of the im plant-supported prosthesis by creating a gingival contour and oral vestibule. On the other hand, the goal of augmentation in esthetic regions such as the anterior region is to ensure a natural feeling and esthetics that are in harmony with the adjacent teeth. This article introduces the roles and techniques of vertical bone and soft tissue augmentation through clinical case re ports and a literature review.

Patients with periodontal disease are also reported to be susceptible to infection of peri-implant tissue. The purpose of this study was to evaluate clinically the effects of periodontal disease on the prognosis of implant treatment in Japanese patients.

The subjects of the survey were 34 Japanese patients who received implants at Tokyo Dental College Hospital, Department of Oral Implantology. Based on the examination of periodontal disease at the first visit, the patients were divided into two groups, 14 healthy patients (N P group) and 20 periodontal disease patients (P group). Remaining number of teeth, bleeding on probing (BOP) and probing pocket depth (PPD) in natural teeth, age-related periodontal bone loss (ArB) score, and resorption degree of bone around implant (at the time of installation of superstructure, and at 3 years after installation) was evaluated. In all cases, appropriate periodontal disease treatment was performed and then implant treatment was performed.

After more than 3 years after installation of the implant superstructure, no significant difference was observed between both groups in BOP, rate of PPD of teeth of 4 mm or more, or even rate of PPD of teeth of 6 mm or more. Not significant difference was observed in the ArB score. No implants fell out during the test period, and the extent of absorption of alveolar bone of the implant unit was slight. However, a significant difference was observed in the extent of absorption of alveolar bone of the implant unit between the two groups.

From the results of clinical parameters of periodontal disease, it is suggested that the risk of worsening of periodontal disease is reduced by performing implant preoperative periodontal disease treatment and maintenance after implant treatment.

This study aimed to clarify the influence of the material of the insert tip of an ultrasonic scaler on the surface of commer cially pure titanium 2 (Cp-Ti) and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP).

Polished specimens of Cp-Ti and Y-TZP scaled with an ultrasonic scaler using plastic and metal tips were measured with a laser confocal microscope, and the measurements before and after scaling were compared. At the same time, the force applied to each specimen during scaling was measured with a compact multi-component dynamometer.

As a result, Cp-Ti increased the surface roughness after scaling for both plastic and metal tips, especially the surface roughness after using metal tips increased greatly. Y-TZP showed little difference between the surface roughness before and after scaling for both plastic and metal tips. In addition, when plastic and metal tips were used, the force applied to Cp-Ti was large. These results suggest that the use of metal tips as well as plastic tips is not a problem for removing dental calculus ad hered to the surface of Y-TZP.

Objectives : Fractures of dental implants are rare incidents. They are, however, a frustrating problem not only for patients, but also for clinicians since they usually involve loss of both the implant and the prosthesis. Goiato et al. proposed that in the case of an implant fracture, complete removal of the fractured implant and the placement of a new implant is the best treat ment option. The aim of this study was to investigate the treatment of 16 cases of fractured dental implant from our previous study, which assessed the incidence of dental implant fractures in ten dental clinics in the Kyushu area.

Materials and methods : The methods used to treat the above-mentioned 16 cases with 17 fractured dental implants were investigated.

Results : The following four treatment methods were used : (1) a fractured small fragment of the implant platform portion was removed, and the original superstructure was reconnected to the implant body in 7 cases (8 implants) ; (2) a fractured implant body was left in the bone and a newly fabricated bridge was delivered using adjacent teeth for support in 1 case, and a fractured implant body was left in the bone and no prosthodontic treatment was performed in 1 case ; (3) a fractured im plant was removed and replaced with a new implant at the same site, and a prosthesis was fabricated in 3 cases ; and (4) a fractured implant body was left in the bone, new implants were placed in the adjacent area, and a new superstructure was fabricated in 4 cases.

Conclusion : In those cases where fractured implants were replaced with new implants, no problem occurred after treat ment. In cases where the original superstructures were reused and connected to the fractured implants, screw loosening and fracture of the superstructure often occurred. Therefore, the results suggest that (3) is the best option for retreatment after implant fracture.