The main causes of failure in core build-up are loss of dowel, root fracture, and coronal leakage. Because conventional methods are limited in how they can combat them, fiber-reinforced resin core build-up is currently the first-choice method, and achieving a supragingival tooth structure, fiber arrangement, and adhesion to the root canal dentin are considered to be important for improving its predictability.

One role played by the supragingival tooth structure is supporting occlusal force, and since its size is the most important factor in improving the fracture resistance of the abutment tooth, orthodontic extrusion and crown lengthening should be actively used to achieve this. Fibers provide effective reinforcement as long as they are positioned at sites subject to tensile stress, and they are most effectively positioned horizontally so that they surround the outermost circumference of the abutment cavity, and vertically so as to straddle the gingival margin line, which is where horizontal fractures are most likely to occur. Before setting the post and core, any remaining plaque, temporary filling, or other material that could prevent adhesion must be thoroughly removed from inside the abutment cavity and from the surface of the post and core, and appropriate pre-adhesion treatment of both surfaces is required. Self-contained chemically cured resin cement (Super-Bond) is suitable for use as adhesive resin cement. If secure adhesion to the dentin can be achieved, whether the direct or indirect method is used is immaterial, but if control of the progress of the adhesion reaction is an aim, then the indirect method is more reliable.

An external dental fistula is a drainage channel formed on the facial skin because of chronic pyogenic inflammation of odontogenic origin. Most sinus tracts appear in the gingiva and are therefore treated immediately by a dentist.

On the other hand, external dental fistulas are rarely seen first during a dental visit because they are not accompanied by dental pain. Because external dental fistulas appear on the facial skin, they are very often seen first at another medical facility, and delay dental visits until later.

In recent years, external dental fistulas have been encountered infrequently, and are difficult to diagnose because there are many diseases that need to be differentiated from each other. Incisional drainage without dental treatment of the causative tooth does not eliminate the infection, and this results in repeated drainage of pus.

So if an external dental fistula is suspected in a medical patient, the patient should be referred to a dentist. Pulp viability is diagnosed by radiographic examination, electric pulp test and thermal pulp test; and after identifying the causative tooth, an infected root canal treatment is performed to remove the infection in the root canal and fill the canal. If the external dental fistula does not heal, an apicoectomy is performed to preserve the tooth. But extraction is the last method in eliminating infection and should be avoided as much as possible.

Membrane perforation during transcrestal sinus floor elevation (tSFE) is a complication of dental implant therapy for an edentulous maxilla. The classification of sinus membrane perforations during tSFE and the recovery method have been reported. However, it is possible to improve diagnosis and treatment outcomes by using a microscope. Therefore, the aim of this paper was to demonstrate the benefit of using a microscope in the repair of membrane perforations under enhanced visualization, leading to potentially improved treatment outcomes and higher implant success rates. Notably, this paper shows the comparative advantages of using microscopes over traditional methods, such as increased accuracy in procedural execution and minimized invasiveness, which collectively contribute to the advancement of minimally invasive techniques in dental implantology. Although the findings, derived from a limited set of clinical scenarios, necessitate cautious generalization, they underscore the necessity for further research. Randomized, controlled trials (RCTs) to validate the clinical efficacy of microscopes in tSFE are needed.

The use of operating microscopes in clinical dentistry has been around for a long time, and tools that were useful when used in combination in various fields have also become widespread. In microscopic oral surgery, the Piezoelectric Device (PED) was considered to be a useful tool to be used in combination with the microscope. This paper describes the advantages and disadvantages of using PEDs under the microscope in oral surgery and implant surgery.