The use of microscopy during microsurgery had the greatest impact on the medical field in the late 20th century. Because early microscopes were only capable of making slow, unidirectional movements, they were inappropriate for neurosurgery, in which the operation always proceeds with various views of the target. Since then, extensive efforts by previous researchers have lead to step-by-step improvements in surgical microscopes. Most of the current surgical microscopes used in the field of neurosurgery adopt an electromagnetic locking system that locks and unlocks the directional and angular movement. Herein, we show the neurosurgical operative procedure, representative diseases encountered during neurosurgery and functions of current microscopes.

Transcrestal (or “internal”) sinus floor elevation (SFE) can be performed when the residual alveolar ridge has adequate vertical (≥6 mm; SA 1 and SA 3 as classified by Misch) and horizontal dimensions. Although this surgical technique is currently established, it has two shortcomings. First, internal SFE is considered a “blind” approach as far as verification of the elevated osteomucosal layer on the sinus floor is concerned. Also, no guidelines supported by scientific evidence are currently available as to the vertical dimension that can be attained by elevation and grafting without injuring this osteomucosal layer. The present investigation explains a new visual controlling method during evaluation of the osteomucosal layer on the sinus floor, which is based on the use of high-powered optical magnification and accordingly has been termed “microscope-controlled internal” SFE (MCI-SFE), and also examines the influence of elevation heights on the frequency of perforation and other complications during and after SFE. Fifty-nine internal SFE procedures were verified with this technique in 43 patients, who were divided into three study groups depending on the planned height of elevation and they received a total of 60 implants. The clinical and radiographic results of this study demonstrated that the risk of injury to the osteomucosal layer and the associated risk of incurring additional complications such as implant loss and sinusitis would increase significantly in the presence of elevation and grafting heights of ≥4 mm. Whenever possible, therefore, elevation of the sinus floor in internal SFE procedures should be less than 4 mm. Using an operating microscope for visual inspection of the osteomucosal layer of the sinus floor improves surgical success and contributes to better outcomes of internal SFE.

In recent years, dental operating microscopes have become more widely used for endodontic treatment. Approximately 20 years have passed since dental operating microscopes were introduced for use in the field of endodontics in Japan. A survey was conducted from 2009 to 2011 to investigate the use of dental operating microscopes for endodontic treatment at Tokyo Dental College Suidobashi Hospital. During the study period, the microscope was used for an average of 316.4 endodontic procedures, most of which were retreatment procedures.

Aim: To investigate the root canal morphology of human maxillary central incisors and mandibular second premolars in a Turkish population.

Methodology: Fifty extracted maxillary central incisors and fifty mandibular second premolars were collected and India ink was injected into the canals. The teeth were demineralized in 5% nitric acid, cleared with methyl salicylate and then examined using stereomicroscope.

Results: The root canal configurations of the central incisors were as follows: Type-I (94%), Type-V (4%), and Type-VII (2%). Those of the mandibular second premolars were Type-I (90%), Type-VI (2%), Type-VII (6%), and Type-IX (2%). The main apical foramen was located in the center of the root apex of maxillary central incisors and mandibular second premolars at frequencies of 70% and 82%, respectively. The highest frequency of lateral canals was found in the apical third of root canals in both incisors (55.5%) and premolars (87.5%). The frequency of apical foramina in both central incisors and mandibular second premolars was 42%. Apical deltas were seen in incisors and premolars at frequencies of 8% and 12%, respectively. Anastomosis between canals was only seen in mandibular second premolars at a frequency of 2%.

Conclusion: The clinician must have an understanding of the complexity of the root canal system and its possible variations in order to achieve a technically satisfactory outcome in endodontic practice.

Variations in the pulp chamber anatomy and root canal configuration, especially in multi-rooted teeth, are a constant challenge for diagnosis and successful endodontic therapy. Knowledge of the most common anatomic characteristics and their possible variations is fundamental. An ideal root canal anatomy is more of an exception than a rule in the routine clinical scenario. This article describes the possible variations in the anatomy of maxillary molar teeth and a report of two cases.

Various types of ultrasonic tips are used with microscope to remove the debris in root canals. However, even after removal of debris by microscope, we can not clearly see the surface condition of the root canal. The present study was conducted to clarify differences in the smear layer formed when using an ultrasonic tip under various conditions (tip type, with/without water, and power level). Sixty sectioned single-rooted specimens without smear layer and smear plugs were divided into 12 groups based on combinations of tip type (diamond tip, stainless steel tip), use/non-use of water, and power level. The ultrasonic tip was gently (5-10 g) pushed against the canal wall and moved vertically along the long axis for 5 s. The root canal surface and cut surface of the specimens were observed by SEM, and then scored. Significant differences were observed in the presence of a smear layer between the control and all test groups (p<0.01). A stainless steel tip used at lowest power with water produced the least amount of smear layer. Smear plugs were frequently formed when the root canal was shaped using a diamond tip with water. The smear layer and smear plug formation varied when using ultrasonic tips under various conditions.

The present study was conducted to clarify the effectiveness of root canal shaping using a stainless steel tip with water in removing the smear layer (SL) and smear plugs (SP). Forty sectioned single-rooted specimens without SL or SP were used. The SL was formed by using a diamond tip (DT) with/without water, and the SP was formed using a DT with water. After shaping with the DT, the specimens were prepared using a stainless steel tip (ST) with water. The specimens were observed by SEM and scored. The SL was effectively removed using the ST at low power, and there was a significant difference in the presence of SL between the lowest and highest powers (p<0.01). The SP, however, was not removed using the ST with water at any power level. It is suggested that the SL can be removed effectively using ST with water, but this approach is inadequate to remove the SP.