During root canal preparation procedures, the potential for instrument separation is always present. Files, a lentulo, a Gates-Glidden (GG) bur or any manufactured obstruction can be left behind in the canal. Nickel-titanium (NiTi) rotary files are in common usage in these days. Despite their undeniable advantages, there is a potential risk of separation within the canals. It is very rapid, unpredictable, and creates a great deal of stress for the practitioner. When an endodontic instrument separates, the best option is to remove it. Ultrasonic instruments and microscopes have improved the success rate for removing separated instruments. But it is difficult and not always possible. Therefore prevention is the key. In this case report, several management methods of separated file in the canal are presented.
Dental Pulp Cavity* ; Root Canal Preparation ; Ultrasonics

No abstract available.
Dental Pulp Cavity* ; Root Canal Preparation*

Screw-in effect is one of the unintended phenomena that occurs during the root canal preparation with nickel-titanium rotary files. The aim of this study was to compare the screw-in effect among various nickel-titanium rotary file systems. Six different nickel-titanium rotary instruments (ISO 20/.06 taper) were used: K3(TM) (SybronEndo, Glendora, CA, USA), Mtwo (VDW GmbH, Munchen, Germany), NRT with safe-tip and with active tip (Mani Inc., Shioya-gun, Japan), ProFile(R) (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper(R) (Dentsply-Maillefer, Ballaigues, Switzerland). For ProTaper(R), S2 was selected because it has size 20. Root canal instrumentations were done in sixty simulated single-curved resin root canals with a rotational speed of 300 rpm and single pecking motion. A special device was designed to measure the force of screw-in effect. A dynamometer of the device recorded the screw-in force during simulated canal preparation and the recorded data was stored in a computer with designed software (LCV-USE-VS, Lorenz Messtechnik GmbH, Alfdorf, Germany). The data were subjected to one-way ANOVA and Tukey's multiple range test for post-hoc test. P value of less than 0.05 was regarded significant. ProTaper(R) produced significantly more screw-in effects than any other instruments in the study (p < 0.001). K3(TM) produced significantly more screw-in effects than Mtwo, and ProFile(R) (p < 0.001). There was no significant difference among Mtwo, NRT, and ProFile(R) (p > 0.05), and between NRT with active tip and NRT with safe one neither (p > 0.05). From the result of the present study, it was concluded, therefore, that there seems significant differences of screw-in effect among the tested nickel-titanium rotary instruments. The radial lands and rake angle of nickel-titanium rotary instrument might be the cause of the difference.
Dental Pulp Cavity ; Root Canal Preparation

Successful endodontic treatment depends on the effectiveness of the cleaning and shaping of the root canal system. Due to the complexity of the structure of root canal system and the particularity of root canal infections, the equipment and technology currently available for root canal preparation hinder the ability to adequately clean and shape the root canal system. In this review, we summarized the difficulties in the control of root canal infection, the new concept of three-dimensional root canal preparation, and its quality control and assessment.
Dental Pulp Cavity ; Root Canal Preparation ; Root Canal Therapy

Dental Pulp Cavity ; Humans ; Root Canal Preparation ; Root Canal Therapy

Dental Pulp Cavity ; anatomy & histology ; Humans ; Root Canal Preparation ; methods

Post-endodontic restorations are both important and challenging for clinical success in endodontically treated posterior teeth. Several options have been proposed to restore endodontically treated molars.In pediatric dentistry, restoration using conventional single crowns, especially for partially erupted molars with insufficient retentive tooth structure, has proven to be difficult. However, the endocrown presents a conservative and esthetic restorative alternative to conventional crowns with post-and-core, as it acquires additional retention within the pulp chamber. The tooth preparation consists of a circular, equigingival, butt-joint margin and a central retention cavity in the pulp chamber that helps to construct both the crown and core as a single unit.This case report describes the esthetic and conservative endocrown restorations of erupting permanent first molars with extensive coronal destruction.
Crowns ; Dental Pulp Cavity ; Molar ; Pediatric Dentistry ; Tooth ; Tooth Preparation

Developments in science and technology include the use of laser as an auxiliary device in treating oral diseases. Nd:YAG laser is convenient and safe to use. Nd:YAG laser irradiation leaves no scabby area on the wound surface, causes a mild reaction postoperation, and promotes high comfort. Therefore, this treatment has attracted increasing attention in the clinical setting. This review enumerates the applications of water-cooled pulsed Nd:YAG laser in hard and soft tissues in oral medicine. Nd:YAG laser in hard tissues can be applied in cavity preparation, acid etching, root canal preparation and sterilization, and dentin desensitization therapy. Meanwhile, the applications of this laser in soft tissues include adjunctive therapy in basic periodontitis treatment, gingival aesthetic treatment, and resection. This review suggests the importance of Nd:YAG laser as an auxiliary device in the clinical diagnosis and treatment of oral diseases.
Dental Cavity Preparation ; Dentin ; Humans ; Lasers, Solid-State ; Oral Medicine ; instrumentation ; methods ; Root Canal Preparation

OBJECTIVETo set up a clinical evaluation method for the matrix system, and compare two matrix systems, Palodent and circumferential, by this method.

METHODS101 molars and premolars with class II cavities, which were suitable for resin filling without shift and incline of the adjacent teeth, were randomly divided into study group (Palodent) and control group (circumferential). There were 79 single cavities and 22 paired cavities. One doctor-in-charge completed all cavities filling. Probes were used to test overhang of the filling. Dental floss was used to detect the proximal contact index before and after cavity preparing and immediately and one week after cavity filling. Questionnaires were filled in by patients immediately and one week afrer cavity filling. The tooth models of the filling side were taken, then two doctors-in-charge were responsible for establishing the model evaluation index and one of them conducted the evaluation for all of the models. SPSS 14.0 software was used to analyze the data.

RESULTSAn evaluation system including questionnaire, clinical examination and tooth model evaluation was set up. There were nine indexes in this system. Moreover, this clinical evaluation system was used in this study. It was found that there were no differences on questionnaire and overhang indexes between the two groups. Palodent matrix system got tighter proximal contact than traditional circumferential matrix system. When filling the paired posterior teeth, Palodent matrix system formed better marginal ridge than circumferential matrix system.

CONCLUSIONPalodent matrix system is better than circumferential matrix system in filling the paired posterior teeth.

PURPOSE: To compare three digital radiographic imaging sensors by evaluating the visibility of endodontic file tips with interobserver reproducibility and assessing subjectively the clarity of images in comparison with the x-ray film images. MATERIALS AND METHODS: Forty-five extracted sound premolars were used for this study. Fifteen plaster blocks were made with three premolars each and #8, 10, 15 K-flexofiles were inserted into the root canal of premolars. They were radiographically exposed using periapical x-ray films (Kodak Insight Dental film, Eastmann Kodak company, Rochester, USA), Digora imaging plates (Soredex-Orion Co., Helsinki, Finland), CDX 2000HQ sensors (Biomedisys Co., Seoul, Korea), and CDR sensors (Schick Inc., Long Island, USA). The visibility of endodontic files was evaluated with interobserver reproducibility, which was calculated as the standard deviations of X, Y coordinates of endodontic file tips measured on digital images by three oral and maxillofacial radiologists. The clarity of images was assessed subjectively using 3 grades, i.e. plus, equal, and minus in comparison with the conventional x-ray film images. RESULTS: Interobserver reproducibility of endodontic file tips was the highest in CDR sensor (p< 0.05) only except at Y coordinates of #15 file. In the subjective assessment of the image clarity, the plus grade was the most frequent in CDR sensor at all size of endodontic file (p< 0.05). CONCLUSION: CDR sensor was the most superior to the other sensors, CDX 2000HQ sensor and Digora imaging plate in the evaluation of interobserver reproducibility of endodontic file tip and subjective assessment of image clarity.
Bicuspid ; Dental Pulp Cavity ; Radiography, Dental, Digital ; Root Canal Preparation ; Seoul ; X-Ray Film