The anatomical variability of primary molars promotes research to improve clinical restorative activity, forensic identification, and industrial development. The objective was to study the morphology of the pulp chamber and its three-dimensional relationship with the external morphology of the tooth. A total of 151 deciduous molars were collected and subjected to three-dimensional imaging analysis in order to determine dental crown (CV) and pulp chamber (PV) volumes, their ratio (VR), pulp chamber roof (PCR) and pulp chamber floor (PCF) area, the furcation length (FD), and morphological peculiarities. The data were compared using the Kruskal–Wallis test in SPSS 26 software. The statistical analysis determined statistically significant differences between the four groups of molars for all variables. Great anatomical variability was observed, especially in the maxillary first molar, the volumes were higher in the maxillary second molar and the highest risk of furcal perforation was seen in the mandibular first molar. Additionally, mandibular second molars with six pulp horns, and some different density images compatible with accessory canals and pulp stones were found. Based on the findings of this investigation, we confirm the great anatomical variability that exists between the maxillary and mandibular molars.

Pulp therapy in primary teeth is a challenge for a dentist, therefore, a better understanding of the anatomical characteristics of this tissue is essential to remedy these deficiencies. The aim of this study was to determine the morphological peculiarities of the root canals of extracted deciduous molars by Cone-Beam computed tomography (CBCT). As such, healthy molars without physiological resorption were collected and sanitized. After analyzing descriptive and inferential statistics, the results show that 56% of lower molar roots have a Weine’s type III canal configuration; the upper and lower second molars are significantly larger compared to the first, with a mean of 8.318 (±1.313) mm and 7.757 (±1.286) mm, respectively. Additionally, the palatine canals exhibited greater volume than the others, with a mean of 3.687 mm³. There are multiple discrepancies in the molars that have been studied in other investigations. The presence of a supernumerary root in the mandibular molars, a smaller dimension of the root canals and a more evident apical angulation are more obvious. The discovery of great anatomical versatility in the posterior dental group is an aspect applicable to root therapy.

The etiology of temporomandibular disorders (TMDs) has been linked to various factors, including functional and psychological factors, which makes it difficult to identify associations between a single etiological factor and the signs and symptoms of TMDs. Objectives: This study aimed to describe the presence of TMD symptoms and their relationship with sleep disturbances and emotional disorders in children and adolescents. Methods: This observational study included Spanish children aged between 8 and 13 years. The measurement instruments consisted of the BRUNI survey for sleep disorders and the Educational-Clinical Questionnaire: Anxiety and Depression (CECAD) survey. A clinical examination was subsequently performed following the DC/TMD guidelines for diagnosing TMDs. Frequencies, means, and standard deviations were applied, along with the prevalence ratio as a measure of association and the chi-square test. The significance level was set at 5%. Results: A total of 128 participants participated in the study with a mean age of 10.89 (±2.15) years. The prevalence of TMDs was 54%, while the most common symptoms were muscle pain at 26%, joint pain at 14%, and a combination of both at 14%. Children who presented muscle pain had a mean anxiety score of 44.87 (±11.85), whereas those without symptoms had a mean score of 36 (±10.78, and 0.03 p-value). The BRUNI index revealed that 78.13% of patients with TMDs had difficulty initiating and maintaining sleep, with a prevalence ratio (PR) of 3.57 (p-value 0.041). Conclusions: The present study reveals that temporomandibular disorders are common in children and adolescents, with 54% presenting at least one clinical sign or symptom. Emotional disturbances and sleep problems were also prevalent, affecting 41% and 56% of participants, respectively. Early interdisciplinary screening is essential to manage the co-occurrence of TMDs, emotional distress, and sleep problems in children.

The prevalence of bruxism in the preschool population varies according to different investigations. The aim of this study was to investigate the prevalence of sleep bruxism and its relationship with social and orofacial factors in children aged 3 to 5 years. Three hundred forty-three preschool children were divided into two groups, one with nocturnal bruxism, as reported by parents, and another without this disorder. Questionnaires were distributed to the parents to determine the children’s family social status and parafunctional habits at the time of the study. The clinical inspection confirmed the presence of certain parafunctional habits and the children’s occlusal characteristics. The data obtained were analysed using descriptive statistics such as frequency chi-square tests to identify the influence of qualitative variables. Of the total sample, 28.9% of preschoolers presented sleep bruxism. The highest prevalence was observed in boys (61.6%) at the age of 5 years (41.4%). Characteristics associated with this pathology were lip incompetence, open bite, crossbite, and overbite, with p < 0.05. Sleep bruxism in preschool children has a higher prevalence in boys and is more frequently expressed from 5 years of age. Open bite, overbite, and crossbite should be considered factors associated with parafunction.

Sleep disorders (SD) in children is a topic of great relevance due to their impact on a child’s general health. This has led us to study their prevalence and the factors that disturb them in the developing population. Using a validated Likert-type questionnaire, different behaviors observed by the parents during the different phases of their children’s sleep were evaluated during the last 6 months. A total of 206 children between the ages of 7 and 17 who attended a dental office participated in the study. The prevalence of SD was 47.6%. There were no significant differences regarding the SD in relation to sex (p = 0.796). The mean total score for children aged 7 to 11 years old was 42.3 (±14.25) compared to 45.44 (±15.51) for the group consisting of children aged 12 to 17 years old, reporting a statistically significant difference among both age groups (p = 0.01). The most frequent disorder was related to initiating and maintaining sleep (64.9%) while the least prevalent were the respiratory sleep disorders (27.2%). Given the high prevalence of these disorders, it is necessary to intercept them during childhood and establish educational guidelines in this regard throughout primary care.

Aim: To determine the root canal taper of primary maxillary molars and the degree of compatibility of various rsotary systems concerning root anatomy. Materials and methods: This in vitro study collected donated first and second primary molars (1 M and 2 M) with mesio-buccal (MB), disto-buccal (DB) and palatal (P) roots canal without physiological resorption, type I according to Vertucci, and root length greater than 4 mm. The teeth were mounted in silicone blocks and scanned with tomographic equipment from which images were reconstructed and analysed with the 3D-Slicer® programme, allowing for the measurement of the diameters of the root canals and the calculation of their tapers. The tapers were compared with the characteristics of the rotary systems: Endogal®, Protaper universal®, Mtwo® and Protaper Next®. MANOVA and interclass correlation coefficient (ICC) tests were used for statistical analysis. Results: After the analysis of 130 root canals, a mean increase in taper in the buccal-palatal (BP) direction was observed in the 2 M (MB:16.7%; DB:16.23%; P:8.86%) and the 1 M (MB: 9.75%; DB: 11.30%; P: 2.26%). In the mesiodistal (MD) direction, the 1 M exhibited an average taper of MB:6.95%, DB:4.67%, P:12.74% and in the 2 M, an average taper of 4.67% for the MB canal; 6.60%; 20.14% for DB and P canals, respectively. Conclusion: The rotary files that presented the best adaptation to the diameter and taper of the root canal were Endogal® and ProTaper Universal® systems.