The osseointegrated implant ad modum Brånemark was initially used in edentulous patients. Later, it was applied to partially edentulous patients and is now widely accepted as a means of prosthetic treatment.

In recent years, peri-implant disease has attracted much interest; a history of periodontal disease has been pointed out as a risk factor. Implants can be applied to patients with periodontal disease if the infection is thoroughly controlled by appropriate periodontal therapy.

Once diagnosed as peri-implantitis, currently there is no definitive established treatment. Rigorous supportive therapy programs are needed for patients with periodontal disease in order to prevent peri-implant disease. It is essential to detect and treat lesions at an early stage based on an appropriate diagnosis.

Implant placement itself is difficult due to loss of alveolar bone in the dentition that led to tooth extraction because of periodontal disease. Considering the anatomical morphology, cases can be handled by applying short implants, tilted implants, cantilever, etc.

By applying a perio-implant prosthesis, it is possible to improve the function and esthetics to protect the supporting tissue and remaining teeth after periodontal disease treatment.

It is well known that determining the stage of implant placement in relation to aesthetics affects aesthetic results. Immediate implant placement at the same time as tooth extraction can reduce the number of surgeries, and probably reduces the physical burden on the patient. However, the surgical procedure is difficult and the aesthetic risk is high. According to the results of 20 years of research, the indications are gradually changing. On the other hand, waiting for a period of time after tooth extraction, called early implant placement, reduces surgical risk. It is generally said that early implant placement is more stable than immediate implant placement. However, it is confusing for the surgeon when setting the stages and selecting the surgical method to be used in combination with implant placement. Therefore, this study considers the appropriate implant placement stage in relation to aesthetics and its surgical method based on the latest knowledge.

We have performed comprehensive periodontal therapy including implant treatment for patients who have lost teeth due to periodontitis and assessed the long-term prognosis of implant treatment for such patients.

The patients were divided into sub-groups by Stage (Ⅰ, Ⅱ, Ⅲ, Ⅳ) and Grade (A, B, C). The treatment outcomes of treated implants were divided into success and failure, and marginal bone loss (MBL) of less than 3 mm was defined as “successful implant treatment”. In contrast, implant failures were divided into four sub-groups (MBL ≥ 3 mm, peri-implantitis, detached due to peri-implantitis and lack of osseointegration). The implant function periods, number of implants placed, presence or absence of bone augmentation, implant brand and superstructure features have been compared among Stage and Grade groups.

The prevalence of peri-implant diseases was significantly higher in the StageⅣ group and patients who have received bone augmentation (BA). The ratio of the group which received BA was significantly higher in both the StageⅢ and Grade C groups. The lack of osseointegration group showed different characteristics from the peri-implantitis group, and which was significantly higher in the type of implant, with BA, and in the single implant prosthesis group, while the functional duration was significantly shorter. The difficulty of treatment and care, and the occlusal forces acting on implants, may increase for patients with severe periodontitis.

We conclude that the Stage and Grade of periodontitis is a risk indicator for having peri-implant diseases. Both precise periodontal and implant treatments are crucial for patients with severe periodontitis.

The treatment of peri-implantitis can be roughly divided into non-surgical treatment and surgical treatment. The disease state of peri-implantitis varies ; bone resorption that appears remarkable in radiographs may improve by non-surgical treatment even if the infection is clinically advanced. Therefore, non-surgical treatment is cumulatively carried out without choosing immediate surgical treatment or removal, even if bone resorption is clearly visible. Non-surgical treatments such as debridement, antiseptic cleansing, antimicrobial photodynamic therapy and antimicrobial therapy may be combined to see the response of the peri-implant tissue. Non-surgical treatment should be continued if any improvement is observed. However, if the drainage continues and no improvement of the peri-implant tissue is recognized, the approach may shift to surgical treatment.

Decontamination of contaminated implant surfaces is important in surgical treatment. In particular, when the infection is prolonged and the bone resorption is advanced, calcifications which adhere tightly besides organic matter such as biofilm may also be found on the implant rough surface. Therefore, decontamination including calcified material is essential in the treatment of peri-implantitis. Some techniques are less effective in decontamination, and others are less suitable as treatments because of the residual heterogeneous elements on the surface of titanium implants after treatment.

In the present study, the effectiveness of non-surgical and surgical treatments for all 218 peri-implantitis treatments carried out in the past 30 years was examined and a clinical evaluation was carried out. The treatment effectiveness of non-surgical treatment was 60.0%, and was 77.5% when combined with surgical treatment.

Purpose : Statins are known to enhance the biosynthesis of bone morphogenetic proteins, which could potentially lead to improved bone mass locally if attached to dental implants. The purpose of this study was to investigate the immobilization of statin drugs on titanium disks via surface treatments by surface characterization and to also determine subcutaneous tissue reactions of statin-immobilized titanium disks during the initial stages of implantation.

Method : As a statin carrier, a fluvastatin/ gelatin complex (FG complex) was immobilized on the surface of titanium disks following alkaline and dopamine treatments. The surfaces of treated disks were examined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In order to examine subcutaneous tissue reaction, the disks were placed under the skin of rats for 1 or 4 weeks.

Results : SEM images of alkaline-treated disks revealed a fine network structure on the titanium surfaces. XPS analysis of carbon (C) and oxygen (O) spectra suggested that the FG complex was immobilized on the titanium disks through adherent dopamine. At 1-week post implantation, lymphocytes infiltration in the connective tissue in contact with all titanium disks was observed in the subcutaneous tissue reaction of rats, and the degree of infiltration was high on the FG complex-immobilized titanium disks. No severe inflammatory reaction such as infiltration of neutrophils was observed. At more than 4 weeks post-implantation, all the disks were covered with fibrous tissue.

Conclusion : Within the limitations of this study, the FG complex could be immobilized on the titanium disks by alkaline and dopamine treatments. Also, the subcutaneous tissue in contact with the FG complex-immobilized titanium disks did not elicit any severe inflammatory response.

We encountered a patient in whom jaw reconstruction by iliac transplantation was performed after tumor resection, and oral cavity function was restored using an electroformed telescope denture.

The patient was a 31-year-old female. The chief complaint was masticatory disturbance accompanied by right mandibular pain. Suspecting a mandibular lesion, biopsy was performed with tooth extraction and osteofibroma was diagnosed. The tumor was resected, and mandibular reconstruction with a titanium mesh tray and the ilium was performed. Implant placement surgery was done in the ilium-transplanted region. After confirming osseointegration, a bar frame was used for the primary structure, and a temporary prosthesis was inserted, resulting in stabilization of occlusion. The electroformed telescope denture was attached and the course was observed.

As of 15 years after prosthesis attachment, no peri-implantitis or mobility based on the periotest value has been noted. In addition, peri-implant abnormal bone resorption was not observed on panoramic radiography or dental cone beam CT. High satisfaction was reported on evaluating patient satisfaction with the prosthesis, and the prosthesis-retaining force of the treatment normalized.

Artificial bone substitutes are widely used in bone regeneration therapy. However, a method for evaluating the resorption of artificial bone and new bone formation has not yet been established. Accordingly, cone-beam computed tomography (CBCT) images of regenerated bone were used, and their changes over time were investigated. Seven participants underwent bone regeneration therapy for dental implant treatment. CBCT scans taken immediately after transplantation and 6-7 months after were used (approved by the Matsumoto Dental University Research and Ethics Review Committee, approval No. 0222, 0313). ImageJ software was used for image-based analysis. After examining the difference between the existing and regenerated bone, the rate of change at the regeneration site was investigated. BV/TV and connectivity showed differences between the existing and regenerated bone; only BV/TV showed a significant difference between 0 and 6-7 months, although the difference was limited. Therefore, the usefulness of a novel and potentially more sensitive parameter was investigated. First, the correlation between the threshold value for the region of interest and the extracted area was analyzed. The inclination of the inflection point was calculated as the “threshold-area relationship (TAR).” The TAR of regenerated bone decreased significantly from 0 to 6-7 months, suggesting its usefulness in evaluating the bone regeneration process.