Clinical performance of dental fiberscope image guided system for endodontic treatment.

We developed a dental fiberscope that can be navigated. As a result we are able to better grasp the device position relative to the teeth, aiming at the lesion more precisely. However, the device position and the precise target setting were difficult to consistently ascertain. The aim of this study is to navigate the position of tip of the dental fiberscope fiber in the root canal with our navigation system. A 3D tooth model was made from the raw dental CT data. In addition, the optical position of the measurement device, OPTOTRAK system was used for registration of the 3D model and actual teeth position and to chase the scope movement. We developed exclusive software to unify information. We were subsequently able to precisely indicate the relation of the position between the device and the teeth on the 3D model in the monitor. This allowed us to aim at the lesion more precisely, as the revised endoscopic image matched the 3D model. The application of this endoscopic navigation system could increase the success rate for root canal treatments with recalcitrant lesion.

In vitro study of anti-suck-back ability by themselves on new high-speed air turbine handpieces.

The anti-suck-back ability of five new high-speed air turbine handpiece models was evaluated in this study. First, suck-back pressure with water displacement within a glass tube was measured. Next, under three different conditions, how many on-off times it takes before fluorescent stains became visible on a piece of gauze at the exhaust vent was counted and the presence of fluorescent stains on the exhaust vents itself was examined. As a result, the water height for each part of one handpiece, the TWINPOWER TURBINE PAR-4HX-O, was below 0 mm. Except for under full emersion, this model, the TWINPOWER TURBINE PAR-4HX-O, did not have any visible fluorescence penetration to the exhaust vent even after 500 on-off switches under fume/mist conditions. Conversely, the other handpieces (Ti-Max X700L, T1 CONTROL, SYNEA TA-98CLED, GENTLE silence LUX 8000B) showed suck-back. In conclusion, the first mentioned new turbine handpiece, the TWINPOWER TURBINE PAR-4HX-O, had a possibility of no suck-back by itself. However, full immersion of the whole head of the handpiece which is not completely sealed must be avoided to prevent liquid intake.

Comparison of three techniques for preparing oval-shaped root canals.

INTRODUCTION: This study compared three techniques for preparing oval-shaped root canals: Anatomic Endodontic Technology (AET), hand instruments (Hedström files; Dentsply Maillefer, Ballaigues, Switzerland), and rotary nickel-titanium (EndoWave; Morita, Osaka, Japan) instruments with regard to cleaning ability and final canal shape. METHODS: Three groups each of 13 extracted human mandibular premolars with oval-shaped canals were used. After canal preparation, teeth were sectioned at three levels (coronal, middle, and apical), photographed to assess cross-sectional canal shape, and processed for histologic evaluation of canal wall planing and the presence of debris. RESULTS: None of the techniques resulted in completely prepared and cleaned canals. No significant difference was found among the three techniques with regard to untouched surface, cross-sectional area, remaining fins, and canal shape at the three levels. Rotary NiTi instruments resulted in significantly less debris in the apical third compared with AET and hand instrumentation. CONCLUSIONS: AET did not perform better than rotary NiTi or hand instruments in oval-shaped canals.

A comparison of techniques for obturating oval-shaped root canals.

This study compared the effectiveness of three obturation techniques for oval-shaped canals. Roots of 42 extracted teeth with oval canals were randomly divided into three groups: (1) ProTaper canal preparation and single cone obturation with matching gutta-percha point; (2) ProTaper preparation plus thermoplastic obturation (Thermafil); (3) Profile .06 taper and matching master cone with lateral condensation. Cross-sectional area of the canal space occupied by sealer cement and gutta-percha was measured in the coronal, middle, and apical thirds using an image analysis software. The percentage of the cross-sectional shape occupied by sealer cement was calculated. The Thermafil group was significantly lower than the single cone group or the lateral condensation group in the middle third (p<0.01) and lower than the single cone group in the coronal third (p<0.05). There were no significant differences between the single cone obturation group and the lateral condensation group in each level.

Dental fiberscope with navigation system for endodontic treatments.

We developed a dental fiberscope with a navigation system. The aim of this study is to direct the position of the tip of the endoscope fiber in the root canal via our navigation system. The distinguishing characteristic of our system is that it could be particularly practical in narrow spaces, such as those involving endodontic treatment typical of root canals. We were subsequently able to precisely indicate the relation of the position between the device and the teeth on the 3D model on the monitor. We inspected our navigation system using both the phantom model and the reconstructed 3D model. From this we could comprehend the relation of the position between the teeth and the device, and aim precisely at the lesion. If we are able to realize the correct position of the endoscope, we can safely and accurately deliver laser irradiation to the lesion. Consequently, the application of the endoscopic navigation system could increase the success rate for root canal treatments with recalcitrant lesions.

Minimally invasive periapical curettage of foreign materials in periapical lesions using a fiberscope.

The design and development of a new fine fiberscope (1.0 mm outer diameter) is described, that includes an irrigation system for endoscopic use. This effectively allows visualisation of fields involved in periodontal disease. This fiberscope has been used in our clinic for seven years to diagnose and treat periapical and periodontal lesions through fistulae and periodontal pockets. The fiberscope has been applied to endodontic surgery for the inspection of root apices and the denuded root surfaces, in addition to the cut root face, rootend cavity and root-end filling after root-end resection. The advantages of endoscopy compared to surgical microscopy are portability and easy adjustment of direct viewing angle to examine around corners without the use of additional mirrors. Furthermore, the fiberscope can be utilised through the sinus tract or a minimal incision without the need for surgical flaps to observe the root surface, periapical tissue and foreign materials before, during and after curettage. The system requires little local anaesthesia, no large incisions, no opening flaps and no sutures. As a result, postoperative symptoms are minimised. Periapical curettage using a fiberscope represents a useful and minimally invasive surgical procedure.