Objectives: Traumatic dental injuries (TDIs) in childhood and adolescence are a potential public health problem given their prevalence and consequences. The aim of this study was to assess the impact of TDIs on the oral health-related quality of life (OHRQoL) of preschoolers and schoolchildren, by synthesizing the available evidence.Methods: A systematic search was conducted in MEDLINE, EMBASE, Cochrane, ScieLo and Lilacs databases since January 1966 until March 2016. The included studies compared OHRQoL between groups with and without TDIs, using validated instruments. The selection process and data extraction were carried out by two researchers independently. A third reviewer resolved discrepancies. Methodological quality was assessed with the Effective Public Health Practice Project's Quality Assessment Tool. Meta-analyses were performed using random effect models, separately for preschoolers and schoolchildren.Results: Of 213 identified articles, 26 studies (involving a total of 4582 patients and 13 601 controls between the ages of 1 and 15 years) met the inclusion criteria.Most of the studies had been published in the last 5 years, and their methodological quality was judged to be moderate. The TDIs group had a significantly higher chance of reporting any impact on OHRQoL than controls for both preschoolers (OR = 1.44; 95% confidence interval [CI]: 1.28-1.63; I 2 = 0%) and schoolchildren (OR = 1.31; 95% CI: 1.04-1.66; I 2 = 70%). In preschoolers, the OR for OHRQoL impact for complicated vs uncomplicated TDIs was 1.53 (95% CI: 1.04-2.26;The social domain was the most affected one in schoolchildren (standard mean difference = 0.34; 95% CI: 0.13, 0.55; I 2 = 68%). Conclusion:Traumatic dental injuries have a negative impact on OHRQoL of both preschoolers and schoolchildren. Outcome standardization to measure OHRQoL impact, such as mean score differences and cut-off points, is needed. Prospective cohort studies are recommended to confirm these findings and to understand how TDIs' impact changes with time. K E Y W O R D Sadolescent, child, preschool, quality of life, tooth injury

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SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully.

SUMMARY:The aim of this study was to assess the morphology of the mesial root canal system of maxillary molars and the frequency of MB2 canals using cone-beam computed tomography (CBCT). A total of 1374 teeth, first maxillary (1MS, n= 802) and second maxillary molars (2SM, n= 572) of 508 Chilean patients between 8 to 77 years were evaluated through CBCT. The mesiobuccal root was evaluated in all three thirds. Root canal morphology was classified according to Vertucci's method. Data were analyzed by Pearson's Chi-square and Cuzick trend tests. MB2 canal frequency in 1MS was 73.44% and in 2MS 42.48%. The most frequent morphology in 1MS and 2MS were Vertucci type II and I, respectively. No statistically significant association was found between frequencies and side or according to gender (P>0.05). A positive association was found as the age increased in both 1MS and 2MS (P<0.001 and P= 0.023, respectively). Given the anatomical complexity of the mesiobuccal root and the frequent presence of the MB2 canal, the clinician must assume the existence of two canals in this root. CBCT scanning is a good way to initially identify this canal in the different root thirds.

Background:The aim of the study was to assess the number and anatomical classification of roots and root canals of first and second mandibular molars using cone-beam computed tomography (CBCT) in a Chilean population. Materials and methods: This study evaluated the CBCT scans of 289 patients aged between 14 and 86 years, obtaining a sample of 1022 mandibular first and second molars. The number of roots and root canals was evaluated according to the anatomical classification proposed by Ahmed in 2016. Data were analysed using Pearson's chi-squared test and ANOVA. Results: Nine hundred fifty-one (93.05%) molars had two roots, while the remaining 71 (6.95%) molars had one root. The most frequent root and root canal morphologies found were: 2 MM M 2 D 1 (29.65%), 2 MM M 2-1 D 1 (22.3%) and 2 MM M 1 D 1 (13.4%) (M -mesial, D -distal), with a total of 32 different anatomical distributions. C-shaped canals were present in 56 molars and were more frequently found in women than in men (7.1% vs. 3.88%; p = 0.024). Conclusions: The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals. The most frequent morphology found in mandibular molars in a Chilean population was two roots and three canals.