Influence of cervical preflaring and root canal preparation on the fracture resistance of endodontically treated teeth.

BACKGROUND: Evaluate the fracture resistance of endodontically treated teeth after cervical preflaring and root canal preparation and to assess the volume of the root canal and the amount of remaining root dentin before and after cervical preflaring. METHODS: Forty-four mandibular incisors were selected using micro-CT scanning and distributed into 4 groups (n = 11) according to the instrument used for cervical preflaring: control group - no cervical preflaring; Gates Glidden - burs size #2 and #3; WXN - 25.07 Navigator instrument; and Easy - 25.08 ProDesign S instrument. Coronal opening was performed, and the canals were prepared with Wave One Gold Primary and filled with an epoxy-resin based sealer and gutta-percha cones. Micro-CT scans were performed before and after root canal instrumentation. All images were reconstructed and assessed for the thickness of mesial and distal root dentin at 3 mm and 5 mm from the cement -enamel junction and for the volume of cervical portion of the canal after preparation. Fracture resistance test was performed applying compressive loads at a crosshead speed of 0.5 mm/min, applied on the palatal aspect of specimens at 135° along the long axis of the tooth. The data were analyzed using ANOVA and Tukey's test (P = .05). RESULTS: Cervical preflaring and canal preparation reduced the dentin thickness (P < .05) and increased the canal volume (P < .05) in all groups at 3 mm an 5 mm. Cervical preflaring with Gates Gliden burs reduced the fracture resistance of endodontically treated teeth (P < .05). CONCLUSIONS: All instruments reduced the dentin thickness and increased the canal volume in the cervical at 3 mm and 5 mm. Gates Glidden reduced fracture resistance of mandibular incisors submitted to cervical preflaring, whereas NiTi instruments did not. CLINICAL RELEVANCE: Cervical preflaring assumes particular importance previously to the root canal preparation because it minimizes the occurrence of operative accidents, and permits more accurate determination of working length and the apical diameter.

Evaluation of the impact of pain from dental urgencies on the patients' oral health- related quality of life: a cross- sectional study

Background. This cross-sectional study aimed to evaluate the impact of pain from dental urgencies on the oral health-related quality of life (OHRQoL). Methods. A sample of sixty-eight patients seeking urgent attention to a primary health unit were included. Clinical diagnosis and sociodemographic data were assessed, dental pain measured by visual analog scale (VAS) and numerical pain rating scale (NPRS). The Oral Health Impact Profile-14 (OHIP-14) instrument was used to measure the OHRQoL. Associations were analyzed using the Student t-test, except for types of urgencies, that were evaluated with one-way analysis of variance (ANOVA) test. Results. The most prevalent urgency type was of endodontic origin (81%). There was no difference between pain and other variables. The type of tooth showed significant differences in OHIP-14 scores. Conclusion. Dental urgencies were associated with a high level of pain and impacted negatively on the patients' OHRQoL. The type of tooth had a positive association the OHRQoL measures.