Quantitative and qualitative comparisons of pulp cavity volumes produced by cone beam computed tomography and micro-computed tomography through semiautomatic segmentation: An ex vivo investigation.

OBJECTIVE: The aim of this study was to measure the volume and visually assess 3-dimensional (3D) virtual models of pulp cavities obtained through semiautomatic segmentation on images from 6 cone beam computed tomography (CBCT) units compared with the reference standard of micro-CT. STUDY DESIGN: Fifteen mandibular premolar teeth were scanned with 6 CBCT units: Prexion 3D Elite, i-CAT Next Generation, NewTom 5G, Cranex 3D, 3Shape X1, and Orthophos SL 3D, using the smallest available field of view and highest resolution settings. Pulp cavity volumes were quantitatively assessed by 2 calibrated examiners. The volumes from each CBCT unit were compared with micro-CT. Qualitative assessment of the 3D reconstructions was also performed. Repeated-measures analysis of variance and the Friedman test compared the CBCT reconstructions to micro-CT. Intra- and interexaminer agreements were calculated with the intraclass correlation coefficient and kappa statistic. RESULTS: The CBCT-based volumes were all significantly larger than micro-CT (P ≤ .0061). Prexion, X1, and Orthophos provided the segmentations that most closely resembled the reference standard. Intra- and interexaminer agreements ranged from good to excellent for quantitative measurements. Interexaminer agreement for qualitative evaluation was substantial. CONCLUSIONS: Semiautomatic segmentation of CBCT images is a feasible method to produce virtual 3D models of the pulp cavity. Prexion, X1, and Orthophos were the CBCT units that resulted in 3D reconstructions most similar to the reference standard.

Evaluation of the Root Canal Morphology of Molars by Using Cone-beam Computed Tomography in a Brazilian Population: Part I.

INTRODUCTION: One of the factors influencing the success of endodontic treatment is anatomic knowledge of the root canal system. Because of the difficulties of using conventional radiographic methods to evaluate root canals, cone-beam computed tomography (CBCT) has been very useful for evaluating the morphology of root canals. The purpose of this study was to use CBCT to evaluate differences in the anatomy of the mandibular first molars with respect to the patient's sex and the location of the tooth in a Brazilian population. METHODS: The study included CBCT images from 198 patients (106 women and 92 men), representing a total of 342 teeth. RESULTS: Of the 342 mandibular first molars included in the study, 0.3% had 2 canals, 75.1% had 3 canals, 23.7% had 4 canals, and 0.9% had 5 canals. The ages of the patients ranged from 19 to 81 years old, with an average age of 48.9 years. Women were more likely to have 2 canals on the distal root of the right side than men were (P < .05). CONCLUSIONS: Because the Brazilian population has differences in root canal morphology compared with other populations around the world, further studies are needed to aid endodontic diagnosis and treatment.

Dental Adhesion to Erbium-Lased Tooth Structure: A Review of the Literature.

OBJECTIVE: The aim of the present study was to conduct a review of the literature about adhesion on erbium laser prepared cavities, related to the specific conditions of the irradiated dentin substrate and the effects on bond strength values. BACKGROUND DATA: Advances in adhesive restorative techniques significantly influenced modern restorative dentistry. The concept of "minimally invasive dentistry" aims to perform more conservative treatment of cavities in which the removal of sound dentin is no longer necessary. This approach, which relies on the concept of adhesion of restorative materials to the mineralized dental tissues, is considered to be a contemporary outcome in dentistry. Similarly, laser technology in restorative dentistry opened new possibilities and strategies as alternatives to conventional treatment. Considering the clinical aspects of the use of erbium lasers for caries removal, cavity preparations, and substrate conditioning, treatment with lasers can be considered to be an efficient technique with wide acceptance by patients. METHODS: Computerized and manual searches were conducted for studies through 2015 that addressed the topic. RESULTS: According to the literature, there is no defined standard protocol concerning the information that articles must provide, making a definitive protocol very difficult to establish. Data varied from the type of adhesive and resin composite used, substrate, and parameters (power, energy density, pulse duration, irradiation time, distance, cooling system) to the bond strength test methodology used. CONCLUSIONS: Further studies are necessary in order to define a standard protocol with positive results and higher bond strength values when using erbium lasers. Detailed information concerning laser parameters should be implemented. Also, longitudinal clinical studies should be developed in the search for new parameters that behave favorably in the irradiated substrate.

Benefits of laser phototherapy on nerve repair.

Post-traumatic nerve repair represents a major challenge to health sciences. Although there have been great advances in the last few years, it is still necessary to find methods that can effectively enhance nerve regeneration. Laser therapy has been widely investigated as a potential method for nerve repair. Therefore, in this article, a review of the existing literature was undertaken with regard to the effects of low-power laser irradiation on the regeneration of traumatically/surgically injured nerves. The articles were selected using either electronic search engines or manual tracing of the references cited in key papers. In electronic searches, we used the key words as "paresthesia", "laser therapy", "low-power laser and nerve repair", and "laser therapy and nerve repair", considering case reports and clinical studies. According to the findings of the literature, laser therapy accelerates and improves the regeneration of the affected nerve tissues, but there are many conflicting results about laser therapy. This can be attributed to several variables such as wavelength, radiation dose, and type of radiation. All the early in vivo studies assessed in this research were effective in restoring sensitivity. Although these results indicate a potential benefit of the use of lasers on nerve repair, further double-blind controlled clinical trials should be conducted in order to standardize protocols for clinical application.