Recently, the use of real-world data (RWD) has been gaining attention in clinical research. RWD is a general term for clinical data that reflects daily medical records maintained in clinics and hospitals. Many clinical studies are being conducted using RWD, contributing to the establishment of evidence that cannot be clarified by randomized controlled trial studies. In Japan, RWD-based research has been conducted in various fields ; however, only a few studies have used RWD for clinical research in dentistry. Hence, this study examined and applied RWD for prosthetic treatment, specifically implant treatment, from the perspective of current laws, clinical research, and the recent trends in academic societies. Although this study does not clearly specify the type of database research that should be done in implant treatment, it could help create a study protocol that clarifies the clinical question of “prosthetic treatment helps extend healthy life expectancy.”

The criterion for success of modern implants was defined at the Toronto Conference as “The resultant implant support does not preclude the placement of a planned functional and esthetic prosthesis that is satisfactory to both patient and dentist.” In other words, esthetics is a crucial requirement for success in implant treatment for both patients and dentists. However, esthetic standards vary with age, gender, era, region, sensibilities, and the like, and the esthetic success desired by patients does not necessarily match the esthetic success envisioned by dentists. Therefore, it is important for dentists to appropriately understand the esthetics desired by individual patients. In this review, we considered the index currently used for evaluating esthetics for a single tooth implant, and examined the criterion for success of esthetic implant treatment.

In the case of implant treatment in the esthetic zone, not only white esthetics but also pink esthetics will be required for optimal esthetic results. In addition, a good relationship of the superstructure and gingiva with the face and lips is indispensable for achieving esthetically pleasing treatment outcomes. Therefore, the criteria for esthetics of anterior implants set a higher standard than for posterior implants. We should observe the following rules in order to achieve successful implant esthetics. 1) Bone thickness of 2 mm or more is necessary to maintain homeostasis of bone around an implant and to support stable labial gingiva. 2) As some degree of crestal bone resorption around implants will occur due to saucerization after abutment connection, the distance between implants should be more than 3 mm and the distance between implant and natural teeth should be more than 1.5 mm in order to preserve sufficient inter-proximal bone to support the interdental papilla between them. 3) Implants should be placed in the optimal position, depth and direction to achieve both esthetics and cleansability. 4) As the defense mechanism of peri-implant soft tissue is considered more fragile than that of natural teeth, adequate keratinized mucosa around implants is needed. Hard and soft tissue augmentation is required for optimal reconstruction of bone and gingival architecture in patients with a severe alveolar deformity. A predictable and effective GBR procedure is considered and clinical ingenuities for preserving keratinized mucosa are discussed.

Oral implant treatment has become an important prosthetic option for defects. Osseointegration is important for the implant body to function in the oral cavity, but soft tissue sealing is essential for long-term functioning. The mechanism of sealing around the implant is similar in structure to the biological widths around natural teeth, but its performance is clearly lower. Due to the anatomical lack of blood flow around the implant, the amount of adhesion-related protein that intervenes histologically with the implant body is small, and epithelial cells adhere weakly to titanium. To improve the soft tissue sealing around the implant, research on the material of the implant body, the surface texture, and the cell activity of the surrounding tissue is still under way. We believe that these considerations affect the prognosis of implant treatment, and that maintenance considering soft tissue clearly extends the life of the implant.

Implant therapy is becoming increasingly common in a variety of tooth loss cases, and yet it may cause complications due to oral bacterial infections. Periodontal disease is known to be a main cause of tooth loss, hence dental implants are also susceptible to peri-implantitis. During the osseointegration process, dental (titanium) implants do not reconstruct periodontal tissue similar to that of natural teeth, weakening the natural immune system around peri-implant tissues. It is therefore necessary to prevent mucous membrane penetration, i.e., antibacterial effect, and improve soft tissue sealing. This paper outlines the antimicrobial effect of titanium implant surface treatment. Titanium surface oxide films are inherently antimicrobial, and the mechanism is closely related to osteoconductivity. Recent studies have also reported a strong immediate bonding effect between surface-treated titanium thin films and soft tissues, which may be applicable for soft tissue sealing of implant abutments.

Objective: The mechanical properties and the amounts of titanium release were compared between grade 4 titanium, according to the Japanese Industrial Standards (JIS), with fine crystal grains improved by severe plastic deformation and that without such processing.

Materials and Methods: Titanium (grade 4) with a diameter of 6 mm, with (G4M) or without (J4S) severe plastic deformation, were cut into 100-mm pieces to determine their tensile strength, yield strength, and elongation using a universal testing machine. To determine hardness, the materials were cut into 5-mm pieces, whose transverse and longitudinal sections were embedded and fixed in resin. After polishing, hardness was determined at 0.3, 1.5, and 3.0 mm from the edges with a Vickers hardness tester. The structures were observed with a microscope. After immersion of each test piece with a diameter of 6 mm and a length of 30 mm in 100 mL of 1% lactic acid solution at 37℃ for 3 months, the amounts of titanium release were determined by inductively coupled plasma-atomic emission spectrometry.

Results: The tensile strength of G4M was about 23% higher than that of J4S (p＜0.05). The yield strength of G4M was about 33% higher than that of J4S (p＜0.05). The elongation of J4S was greater than that of G4M (p＜0.05). The hardness of G4M was higher than that of J4S (p＜0.05). The hardness of G4M did not vary with the measurement site. Structural observation demonstrated that the crystal grains of G4M were finer than those of J4S. The amounts of titanium release did not differ between J4S and G4M.

Discussion and Conclusion: The tensile strength, yield strength, and hardness of G4M with finer crystal grains were superior to those of J4S, suggesting that G4M is more suitable than J4S as an implant material for preventing biological and mechanical complications.

Implant placement in a residual ridge with high bone resorption in the maxillary molar region is difficult by general implant placement methods. We treated a 56-year-old woman, and were able to achieve initial fixation at both the residual ridge and the nasal cavity side wall by palatal tilted implant placement due to little bone of the maxillary sinus. This implant placement method is minimally invasive, with the potential to avoid bone augmentation such as sinus floor elevation. It is necessary to examine more cases in the future.