Effects of root canal enlargement on unprepared areas and coronal dentine thickness of three-rooted maxillary first premolars with different root configurations: A stepwise micro-CT study.

AIM: To evaluate the effects of progressive root canal enlargements on the unprepared surface area and remaining dentine thickness of three-rooted maxillary first premolars with different root configurations. METHODOLOGY: Thirty three-rooted maxillary first premolars with three root configurations (n = 10) were selected and scanned in a micro-CT device. The root canals were sequentially enlarged with rotary instruments sizes 30.02 (step 1), 30.04 (step 2) and 30.06 (step 3). After each step, a new scan was taken. Analysed parameters included morphometric measurements (length, volume and surface area), number of static voxels and minimal dentine thickness. Statistical analyses were performed with one-way anova post hoc Tukey tests and paired sample t-test at a significance level of 5%. RESULTS: No statistical differences were observed amongst groups regarding the morphometric parameters and static voxels (p > .05). The minimal dentine thickness of the distobuccal root significantly changed depending on the root configuration (p < .05), whilst no differences were observed in the other roots (p > .05). A great variation in the position of the minimal dentine thickness was observed after preparation. Overall, mean percentage reduction in dentine thickness was higher in the buccal roots than in the palatal root (p < .05). In the mesiobuccal and distobuccal root, the number of slices with minimal dentine thickness lower than 0.05 mm increases 2 to 3 times and 3 to 4 times, respectively, from steps 1 to 3. CONCLUSIONS: Instruments sizes 30.02 and 30.04 can be safely and effectively used to enlarge the buccal and palatal canals of three-rooted maxillary first premolars.

The applicability of ultrasound in the diagnosis of inflammatory and obstructive diseases of the major salivary glands: a scoping review.

OBJECTIVES: The purpose of the present scoping review was to determine the contribution of ultrasound images in the diagnosis of inflammatory and obstructive diseases of the major salivary glands (MSGs). METHODS: A search of studies of ultrasonographic assessments of human samples was performed in several electronic databases and grey literature up to July 2021. The extracted data were the examined MSG; the diagnostic value of ultrasound (sensibility, specificity, positive- and negative predictive value, accuracy); features of lesions, including number, echogenicity, echotexture, form, margins, size, posterior acoustic aspect, and location; and related clinical information, such as swelling, palpation, sensible to pain, salivation, lymph nodes, recurrence, duration, and causes. RESULTS: After verifying the eligibility criteria, 90 articles focused on detecting inflammatory, and obstructive diseases of the MSG were gathered, with variable study designs and size samples. A wide variety of pathologies were assessed, including sialolitiasis (n = 45), acute sialadenitis (n = 30), chronic sialadenitis (n = 25), granulamatous diseases (n = 15), Kuttner's tumor (n = 11), juvenile recurrent parotitis (n = 9), abscess (n = 7), post-radiotherapy sialadenitis (n = 6), sialadenosis (n = 9), abscess (n = 7), IgG4-related disease sialadenitis (n = 5), HIV-sialadenitis (n = 4), obstructive sialadenitis (n = 3), iodinated contrast-induced sialadenitis (n = 2), and pneumoparotitis (n = 1). Most studies were case reports or series of cases. Few studies exhibited data about the accuracy of ultrasound in detecting MSG diseases. CONCLUSIONS: The present scoping review concluded that ultrasound aspects of different MSG pathologies are similar but contribute to their differential diagnosis and can be considered as a valuable initial method for assessing the MSG of adults and children.