Analysis of the Effect of Exams on Perceived Stress and Temporomandibular Joint Status in Physiotherapy Students: A Pilot Study.

Background and Objectives: Temporomandibular disorders or dysfunction (TMDs) encompass a range of complex conditions that impact the temporomandibular joint (TMJ), chewing muscles, teeth, and/or their supporting tissues. Stress is one of the most associated factors studied as a TMD predictor. The aim is to figure out the influence of stress on TMJ status and salivary cortisol in university students during and before exams. Materials and Methods: The study was non-experimental, employing a longitudinal, analytical, observational cohort design. The study population consisted of students enrolled in the physiotherapy degree program at the Alfonso X El Sabio University (Madrid, Spain). Data were collected during two distinct academic periods: the first period was characterized by low academic stress and no exams, and the second period coincided with the high academic stress of final course exams. The collected results included sociodemographic data, assessment of TMJ status (Fonseca Index), evaluation of muscle evaluation (masseter, upper trapezius, and sternocleidomastoid) using a MOXY Monitor (muscle oxygenation) and Neurotrac® (surface EMG, sEMG), assessment of perceived stress (PSS-14), and measurement of salivary cortisol (enzyme immunoassay with Elisa). The statistical analysis was conducted with a confidence level of 95% (p ≤ 0.05) and asymptotic or bilateral significance. Results: 70 students were analyzed during two different measurement periods. According to the Fonseca Index, initially, 37.14% of the analyzed students showed mild TMDs, 17.14% moderate TMDs, and 45.72% showed no TMDs. In general terms, stress increased with age and is related to female sex, maximum mouth opening decreased with age, oxygen saturation decreased with age and academic stress, and myoglobin concentration was related to age. Furthermore, muscle contraction decreased during higher academic stress and increased with age. For women, age was a risk factor for suffering from TMDs, and stress worsened the transition from having TMDs to having no TMDs in both sexes. Conclusions: Academic stress influences TMJ status and muscle outcomes such as oxygen saturation, myoglobin concentration, and muscle contraction, although more research is needed.

Association between dental agenesis and delay in dental development: a preliminary study in a Spanish paediatric population in relation with Dental Anomaly Pattern (DAP).

BACKGROUND: The association between dental anomalies has been studied, giving rise to the concept of Dental Anomaly Pattern (DAP). Tooth agenesis has been associated with alterations such as molar infracclusion, taurodontism and delayed dental development. The aim of this study was to evaluate the dental development pattern in patients with non-syndromic dental agenesis, in comparison with a control group. METHODS: Dental and chronological age was analysed in a sample size of 204 orthopantomographs divided into a study group (n = 104) and a control group (n = 100) with the Demirjian Method. Intra and intergroup differences in chronological and dental age, and the correlation between them were calculated by statistical analysis with a 95% confidence level (p < 0.05). RESULTS: Dental age exceeded chronological age both in the control group and in the study group. Statistically significant differences (p = 0.004) were found when comparing the difference between chronological and dental age in the study (-0.16 ± 1.12) and control group (-0.58 ± 0.90). Regarding sex and age intergroup differences, the results were only statistically significant in the girls' group (p = 0.017), and the age over 8 years old (p < 0.05). There were no significant differences in tooth development depending on the number of missing teeth or the affected tooth group, but there was a delay in the development of the homologous tooth contralateral to the absent one in 14.9% of patients. CONCLUSIONS: The difference between chronological and dental age in permanent dentition is significantly lower in Spanish children with non-syndromic agenesis compared to a control group, presenting a lower dental age than chronological age than children without non-syndromic agenesis.

Accuracy assessment of dental age estimation with the Willems, Demirjian and Nolla methods in Spanish children: Comparative cross-sectional study.

BACKGROUND: The objective of this study was to evaluate and compare the validity and accuracy of the Willems, Demirjian and Nolla methods in predicting chronological age in a Spanish ethnicity population. METHODS: A sample of 604 orthopantomographs of Spanish children aged 4 to 13 years was evaluated by two independent evaluators. Descriptive statistics were applied to calculate the chronological age and dental age, presenting the mean and standard deviation. The difference between dental age and chronological age was calculated for each method. A positive result indicated an overestimation and a negative figure indicated an underestimation. The Wilcoxon test for paired data and Spearman's correlation coefficient were applied by age groups and sex to compare the chronological age and dental age of each method (that of Willems, Demirjian and Nolla). Statistical tests were performed at a 95% confidence level. RESULTS: The interexaminer agreement was 0.98 (p = 0.00), and the intraexaminer agreement was 0.99 (p = 0.00). The Willems method significantly overestimated the age of boys (0.35 years (0.93)) and girls (0.17 years (0.88)). The Demirjian method significantly overestimated the age of boys (0.68 years (0.95)) and girls (0.73 years (0.94)). The Nolla method significantly underestimated age in boys (0.44 years (0.93)) and girls (0.82 years (0.98)). CONCLUSIONS: In the Spanish population, the use of the Demirjian method for legal and medical purposes is frequent. This study reveals that the Willems method is more appropriate due to its greater precision in estimating dental age.

Comparative Analysis of the Comfort of Children and Adolescents in Digital and Conventional Full-Arch Impression Methods: A Crossover Randomized Trial.

The aim of this study was to evaluate the comfort of children and adolescents with conventional full-arch dental impression methods compared to two intraoral scanners (iTeroTM and PrimescanTM). METHODS: A monocentric, analytical, controlled crossover study was designed to compare conventional impression and digital impression with two intraoral scanners (iTeroTM and PrimescanTM) in children and teenagers. Patient comfort was evaluated using a 100 mm VAS scale adapted to Spanish and for children. A descriptive and analytical statistical method was conducted with a confidence level of 95% (p ≤ 0.05) and asymptotic or bilateral significance. RESULTS: A total of 51 subjects were enrolled in the study (mean age = 12.35 years). Although the group of 10-14-year-olds was the most numerous, gender was equally distributed among the age groups. None of the variables on the VAS scale showed differences between the gender categories (p > 0.05). There were differences (p < 0.05) with respect to the age categories, as the middle adolescent group showed the worst general perception and total comfort during the conventional impression. Statistically significant differences were found between all VAS scale items and the three impression methods (p < 0.05). CONCLUSIONS: The digital impression technique is superior in terms of total comfort to the conventional alginate impression in children and adolescents.

Accuracy Analysis of Digital Models from Intraoral Scanners and 3D-Printed Casts in Children and Teenagers.

PURPOSE: The aim was to analyze the accuracy of digital models and 3D-printed casts from full-arch digital impressions using two intraoral scanners (iTeroTM and PrimescanTM). MATERIALS AND METHODS: A crossover reliability study was designed, scanning children and teenagers with iTeroTM and PrimescanTM. Accuracy was evaluated by measuring intercanine, intermolar, and ipsilateral canine-molar distances intraorally and comparing these measurements with those from plaster casts, digital models obtained with intraoral scanners, and 3D-printed casts. A paired comparison and a general linear model with a one-way repeated measures ANOVA procedure were carried out with a confidence level of 95% (p ≤ 0.05). RESULTS: A total of 51 subjects were analyzed (mean age 12.35 ± 2.57). Statistical differences (p < 0.05) were found in the upper and lower arch regarding accuracy in comparison to intraoral measurements, except for the iTeroTM-printed cast and canine-molar upper right and intercanine lower distances (p > 0.05 for all comparisons). Regarding a comparison between reproduction methods, the plaster cast oversized the intercanine upper distance in comparison with both intraoral scanners' digital models and the PrimescanTM-printed cast (p = 0.001), but there were no differences in the lower arch (p > 0.05 for all comparisons). CONCLUSION: Intraoral scanners reproduce tooth structures with similar accuracy to conventional methods.

In vitro analysis of the influence of the thermocycling and the applied force on orthodontic clear aligners.

The mechanical properties of polyurethane dental aligners have been studied in an oral environment at 37°C and subjected to thermal cycling between 5°C and 55°C for long periods of time at different mechanical stresses. The aim is to determine the efficacy of the orthodontic aligner at different stress levels, the effect of thermal cycling with therapy time on tooth position correction. Sixty aligners with the same design were studied applying tensions of 0, 3 and 30 N and determining the deformation at different times from 1 to 760 h. Half of these aligners were subjected to stresses submerged in artificial saliva at 37°C and the other half were subjected to thermal cycles between 2°C and 55°C in salivary medium. Deformation was determined using a high-resolution stereo magnifier and ImageJ image analysis software. Water adsorption by the polyurethane was determined at the different test times. The results showed that in the unloaded aligners there is no appreciable deformation, but with thermal cycling there is a light shrinkage of the aligner due to the semi-crystallization process (ordering of polymeric chains) of the polyurethane. When applying loads of 3 and 30 N, creep curves with constant deformation transition zones can be seen. The transition zones decrease as the applied mechanical load increases. In addition, the significant effect of thermal cycling on the reduction of the transition zone of the aligners has been demonstrated. The transition zones are optimal for dental correction as constant stresses are exerted for tooth movement. The effect of thermal cycling shortens the constant deformation zone and reduces tooth alignment time. It was observed that the absorption of water in the aligner is constant after 1 h of immersion and does not exceed 0.4% by weight of absorbed water.

Evaluation of the Relationship between the BMI and the Sequence and Chronology of Eruption in Permanent Dentition in Spanish Population.

The aim was to analyze the relationship between BMI (body mass index) and the sequence and chronology of the eruption of permanent teeth in a sample of Spanish children. Methods: The study design was descriptive, cross-sectional, observational, and epidemiological. Patients of pediatric age were included. Emerged teeth, and patient's age, race, and sex were recorded. The nutritional status of the child was assessed by calculating the BMI, according to the WHO parameters. Statistical analysis was carried out with a confidence interval of 95%. A prediction model with logistic regression models was obtained. Results: A total of 725 pediatric patients between 4 and 14 years old were analyzed. BMI acts as a predictor variable for eruption symmetry, as it was most frequent in overweight children (p < 0.001). The probability of symmetry in dental eruption increases for South American children, for an extra month of age, and each meter of height. BMI had an influence in the first tooth to appear only in the fourth quadrant. BMI did not seem to influence present teeth, and the sequence of permanent dental eruption was not influenced by the BMI category. Conclusions: Age, weight, height, and BMI act as significant predictors for eruption symmetry. BMI does not produce alterations in the eruption sequence of the permanent dentition.

Evaluation of the accuracy of the Nolla method for the estimation of dental age of children between 4-14 years old in Spain: A radiographic study.

The aim of this study was to estimate the age of subjects from their dental age by showing the different stages of tooth development using the Nolla method in a Spanish population sample considering the gender, age group, and the development of the two dental arches. The sample consisted of 604 orthopantomographs corresponding to Spanish children (male: 302 and female: 302) aged from 4 to 14 years old. The resulting chronological and dental ages were compared using Student's t-test. We obtained a good index of agreement between the evaluators and good internal consistency in the evaluation of the ages of the teeth. In general, the dental age estimates were lower than the chronological ages, obtaining an underestimation with the application of the Nolla method. In the male group, the average dental age of the maxillary teeth was 8.36 years and that of the mandibular teeth was 8.40 years, compared to the chronological age of 8.84 years in both cases. In the female group, the average dental age of the maxillary teeth was 7.76 years and that of the mandibular teeth was 7.88 years, compared to the chronological age of 8.70 years in both cases. On applying the Nolla method to our sample, a significant overestimation was observed only in children aged between 4 and 6.9 years. The Nolla method can be used as a complementary tool for estimating age in children of Spanish origin. The application of this method is more favourable in the case of individuals evaluated under the law applied to minors. In general, with this method, age is underestimated, but the calculations involved are reliable, and greater precision has been observed in male than in female. The data from this study can be used as a reference to determine the dental maturity of Spanish children and to estimate their ages.