Digital Photocolorimetric Analysis of In Vitro Tooth Color Changes.

OBJECTIVE: Tooth color matching is challenging, and digital photocolorimetry using eLABor_aid (eLAB) provides objective evaluation through polarized photographs. However, its comparability with spectrophotometry remains unclear. METHODS AND MATERIALS: Bovine incisor root canals (n=30) were prepared to simulate an incomplete root apex. The teeth were randomly assigned to three groups based on intracanal medication: control (without medication); calcium hydroxide/propylene glycol; and triple-antibiotic paste (n=10 each). Tooth color was assessed using both eLAB and spectrophotometry. Measurements were taken at the crown medio-cervical region on five-time intervals (baseline, 1, 3, 7, and 14 days). Statistical analysis included two-way repeated-measures ANOVA, Sidak post hoc and Pearson's correlation test (α=0.05). RESULTS: No significant differences were observed between the two methods for either medication or follow-ups (p>0.05). Triple-antibiotic paste exhibited higher color variation (p<0.05). After 7 days, all groups presented significant color changes (p<0.05). Moderate to high correlations (R2 from 0.51 to 0.84, p<0.0001) were found between both methods for all groups at all intervals. CONCLUSION: The eLAB is a reliable method for detecting tooth color changes, and its results are comparable to spectrophotometry analysis.

Fracture Resistance and Failure Mode of Custom-made Post-and-cores of Polyetheretherketone and Nano-ceramic Composite.

CLINICAL RELEVANCE: Custom-made post-and-cores of polyetheretherketone (PEEK) and nano-ceramic composite showed good fracture resistance and failure mode. Clinicians should be aware that these materials might be an efficient alternative for post-and-cores, because they promote esthetics while reducing the risk of root fractures. SUMMARY: Purpose: The purpose of this study was to evaluate the fracture resistance and failure mode of custom-made post-and-cores manufactured with different esthetic materials.Methods and Materials: A total of 48 mandibular premolar extracted teeth were selected, endodontically treated, and prepared to receive the posts. Specimens were randomly divided into four groups (n=12/group): group 1, polyetheretherketone (PEEK, Degos; G1); group 2, nano-ceramic composite (Lava Ultimate, 3M ESPE; G2); group 3, cast metal post (NiCr alloy, control; G3); group 4, fiberglass post (Whitepost, FGM, control; G4) customized with a nano-hybrid resin composite (Z250, 3M ESPE). Experimental post-and-cores (G1 and G2) were manufactured with a computer-aided design/computer-aided manufacturing system. All posts were cemented with self-adhesive resin cement (Rely X U200, 3M ESPE), and specimens were stored in distilled water at 37°C for 60 days. A universal testing machine was used to measure the fracture resistance (0.5 mm/min at an angle of 45° to the long axis of the tooth). Fractures were classified as repairable or catastrophic. One-way analysis of variance with Tukey post hoc and χ2 tests for independence and Bonferroni adjustments were applied (α=0.05).Results: The fracture resistance values (mean ± SD, in newtons) were 379.4 ± 119.8 (G1), 506.4 ± 138 (G2), 939.6 ± 146.5 (G3), and 449.6 ± 66.5 (G4). Only G3 exhibited a significant difference (p<0.05). The χ2 test showed an association between failure mode and post-and-core material [χ2(3) = 23.65; p<0.001]. After Bonferroni adjustment, only G3 presented a higher than expected incidence of catastrophic failures (p<0.001). In the remaining groups, most failures were repairable and related to debonding.Conclusions: Customized post-and-cores of PEEK and nano-ceramic composites exhibited good mechanical performance. Their fracture resistance was comparable to that observed for fiberglass customized posts, yet lower than that for cast metal posts. For PEEK post-and-cores, in particular, additional studies are needed to improve adhesiveness and reduce the risk of debonding.

Impact of root fillings and posts on the diagnostic ability of three intra-oral digital radiographic systems in detecting vertical root fractures.

AIM: To evaluate (i) the accuracy of three intra-oral digital systems in detecting vertical root fractures (VRFs); and (ii) the influence of different intracanal conditions (without filling, filled with Gutta-percha and metal or fibreglass post). METHODOLOGY: Forty single-rooted human teeth were decoronated and the root canals prepared. VRFs were induced using a universal testing machine on 20 teeth. Radiographic images were obtained using the paralleling technique with three different horizontal angulations on conventional E/F film, two storage phosphor plates (Digora Optime and VistaScan) and one sensor system (SnapShot). All teeth were radiographed with all intracanal conditions tested. All images were evaluated by five examiners. After 30 days, 25% of the images were reviewed. Areas under ROC curves, sensitivity, specificity, accuracy, positive predictive and negative predictive values were compared by anova. RESULTS: The weighted kappa values for intra- and interobserver reproducibility were 0.48-0.74 and 0.57-0.66, respectively. The sensitivity revealed a significant difference between imaging modalities, with higher values for SnapShot (0.53) and VistaScan (0.46), followed by the film (0.41) and Digora (0.38). The area under the ROC curve for SnapShot (0.82) was greater than for the other systems in the teeth with a fibreglass post (VistaScan: 0.70; Digora: 0.64; film: 0.60). CONCLUSION: All systems gave a similar performance for detecting VRFs; all gave a good performance in the absence of intracanal materials, but performed less well in the presence of a metal post or Gutta-percha. In teeth with a fibreglass post, digital systems with higher resolution should be used.

Localización efectiva de un segundo conducto radicular en incisivos inferiores mediante magnificación, radiografía y diafanización / Effective location a second root canal in lower incisors by magnification radiography and diaphanization

Objetivo: Evaluar in vitro, la efectividad del método visual y radiográfico, comparándolos con la técnica de diafanización en la detección del segundo conducto radicular de incisivos inferiores tratados endodónticamente. Material y métodos: Fueron analizados 133 dientes incisivos inferiores permanentes, tratados endodónticamente, a través de métodos visuales (con y sin auxilio de magnificación), radiográficos y de diafanización. El análisis radiográfico fue realizado en negatoscopio utilizando una lupa estereoscópica (10X). Posteriormente, fue realizada la remoción completa de la obstrucción provisional para la exploración visual con y sin auxilio de microscopio clínico (MO) en un aumento de 12X. Finalmente los dientes fueron diafanizados y almacenados en salicilato de metila para posterior análisis. Dos evaluadores calibrados registraron los datos referentes a la presencia o no del segundo conducto radicular para cada uno de los métodos utilizados. Resultados: El análisis radiográfico mostró la presencia del segundo conducto en 24 dientes (18,05%. Visualmente, fue encontrado en 4 dientes (3,00%) sin magnificación y en 16 dientes (12,03%) con ayuda del MO. A través de la diafanización, 34 dientes (25,95%) presentaron segundo conducto. Conclusiones: La asociación de técnicas radiográficas y la magnificación visual obtenida con la utilización del MO se muestran como los aliados clínicos más efectivos para la localización del segundo conducto en incisivos inferiores.

Objective: To evaluate in vitro the effectiveness of the visual, radiographic and clearing technique on detection of two root canals in mandibular incisor teeth endodontically treated. Material and methods: One hundred thirty-three human permanent lower incisors were anlyzed through visual methods (with and without magnification), radiographic and clearing technique. Radiographic analysis was performed in light box using a stereomicroscope (10X). Then, the temporary filling of al specimens was removed for visual exploration with and without clinical microscope (OM) (12X). Finally the teeth were submitted to clearing technique and stored in methyl salicylate for subsequent analysis. Two calibrated reviewers recorded data about the presence or absence of the second root canal for each of the used methods. Results: Radiographic analysis showed the presence of the second root canal in 24 teeth (18.05%). Visually, it was found in 4 teeth (3.00%) and 16 teeth (12.03%) without and with the use of OM, respectively. Through clearing technique, in 334 teeth (25.95%) it was found the second root canal. Conclusion: The association of radiographic techniques and visual magnification with the use of MO has been shown as the most effective clinical partners to locate the second root canal in mandibular incisors.