Sonia Patricia Plaza-Ruíz

Objective: To determine the ideal site for mini-screw (MS) insertion in the mandibular symphysis by obtaining total, intraosseous and extraosseous height and depth measurements in this anatomical region in relation to the mandibular anterior teeth and further categorise the results by sex and age. Design: Cross-sectional study. Settings: Cone-beam computed tomography (CBCT) images were analysed from existing clinical records. Methods: CBCT images of 90 patients were examined from a single centre at UniCIEO University. The sample was divided into three age groups: G1 = 30 patients aged 9–13 years; G2 = 30 patients aged 14–23 years; and G3: 30 patients aged 24–50 years. Total, intraosseous and extraosseous height and depth measurements of the mandibular symphysis were obtained at the lower central incisor (LCI), lower lateral incisor (LLI) and lower canine (LC), along the long axis of each respective tooth, by a calibrated operator. For statistical analyses, t -tests and Mann–Whitney U-test, analysis of variance (ANOVA) and Kruskal–Wallis test were used. Two-way ANOVA was applied for variables with significant differences ( P <0.05). Results: Sex-related differences were observed, with male patients presenting greater measurements than female patients, including total height at LCI (mean difference = −2.54, 95% confidence interval [CI] = −3.93 to −1.17) and LC (mean difference = −3.12, 95% CI = −4.71 to −1.54), as well as intraosseous height at LCI (mean difference = −3.00, 95% CI = −4.32 to −1.68) and LLI (mean difference = −2.24, 95% CI = −3.39 to −1.08). Conclusions: An age-related increase in mandibular symphysis height and depth was observed. With respect to the ideal MS dimensions and the optimal site for orthodontic skeletal anchorage, MSs with a length of 20–28 mm may be placed vertically and deep in the lower vestibule of the mandibular symphysis, in the region of the lateral incisor and canine.

Objective: To compare the impact on Oral Health Related Quality of Life (OHRQoL) and pain perception between adult patients undergoing fixed conventional bracket treatment (FCBT) and those undergoing clear aligner treatment (CAT) during the first three months of orthodontic treatment (OT).

Objective: To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis. Design: Three-dimensional analysis of stresses and total strain of the dentition with three Class II correctors. Setting: Computational study. Methods: Three-dimensional finite element models of Class II elastics, the Forsus Fatigue Resistant Device (FRD) and the Carriere Motion Appliance (CMA) were constructed from a cone-beam computed tomography (CBTC) image of an orthodontic Class II patient. The distribution of stress (von Mises and principal stress) and the total strain (mm) in maxillo-mandibular dentition, PDL, cortical and trabecular bone were analysed. Results: The highest von Mises yield and the maximum principal stress in the three models were found at the teeth, followed by the cortical bone, trabecular bone and PDL. The maximum stress and total deformation were located at the upper canines and lower molars in the Class II elastics and CMA models, in the upper first molars in the Forsus FRD and CMA, and in the lower first premolars in the Forsus FRD. In addition, stress was distributed in the anterior and posterior regions of the teeth, and the total deformation was found in the distal direction in the upper arch and in the mesial direction in the lower arch. Conclusion: The stress concentrations in the three models were located close to the active components of each appliance, producing specific patterns of stress distribution and displacement that should be taken into account when planning the type of appliance to be used for the correction of the Class II malocclusion.

The aim of this study was to evaluate the stress distribution in cortical and cancellous bones and within the screw when a stainless steel extra-alveolar screw (EA-S) is inserted into the retromolar region of the mandible using the finite element method (FEM). The stress values in the EA-S were highest at 60 & DEG; with horizontal (shear) force and lowest at 90 & DEG; with axial force. In the bones (cortical and cancellous), the stress value was greatest at 90 & DEG; with horizontal force. Greater stability of the screw may be achieved by tilting it to the force when horizontal loads are applied.

Malocclusion can affect the oral health-related quality of life (OHRQoL). The influence of the orthodontic treatment need (OTN) and the type of brackets on OHRQOL is not clear. The aim of the present study was to determine the relationships between OTN and the bracket type and OHRQoL during the first 6 months of orthodontic treatment (OT) in adult patients. This cohort study was conducted at the Department of Orthodontics of a private university. A total of 216 patients aged ≥18 years participated in the study (106 patients with conventional brackets and 110 with self-ligating brackets). The OHRQoL was evaluated using the 14-item Oral Health Impact Profile (OHIP-14) at 5 time points - before OT (T0), and at 24/48 h (T1), 1 month (T2), 3 months (T3), and 6 months (T4) after the installation of the orthodontic appliance. The OTN was evaluated with the dental aesthetic index (DAI) by 2 previously calibrated operators. For the statistical analysis, the χ2 test and the Mann-Whitney U test were used. Additionally, Poisson regression models were performed. The evidence of an association between OHRQoL and OTN was found only at T3 (p = 0.0095). No association was found between OHRQoL and the bracket type. However, in the regression models, OHRQoL was statistically significantly worse at T3 in the group with a greater OTN (IRR (incidence rate ratio) = 1.34; 95% CI (confidence interval): 1.21;1.48) and at T4 in the self-ligation group (IRR = 1.23; 95% CI: 1.12;1.36). The OHRQoL was affected in the same way at the beginning of OT, regardless of OTN and the bracket type used. However, a worse OHRQoL was observed at 3 months in subjects with greater OTN and at 6 months in patients with self-ligating brackets.

The purpose of this article was to describe a simple graphical driven method for determining the necessary two-vector mechanics (TVM) as an alternative solution to the ideal or single force. In orthodontics, some tooth movements are difficult to achieve, mainly because of the impossibility of getting the point of application for the necessary force system. Given two points in biomechanically accessible areas, adding together two vectors applied to those points will result in an equivalent force system. The method was developed based on previous research, 3,880 hypothetical cases were analyzed to determine the trends between the resulting forces and their relative locations. A graphical driven TVM method (GTVM) for establishing the necessary TVM is presented in a manner that combine different procedures from the traditional method that simplify the analysis and may allow the user to perform more complex orthodontic cases making easier to compare systems of force equivalents.

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It is important to complement the scientific literature with the data regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on the social, work and health practices as well as on the daily life of dentists, and to promote adequate public policies. The aim of the study was to explore the impact of the COVID-19 pandemic on the career plans of dentists in Colombia. As part of global research on the impact of COVID-19 on dentistry, a crosssectional survey was administered via digital media to dentists in Colombia. The validated questionnaire included inquiries regarding sociodemographic variables, the perception of the risk of contagion with COVID-19 and the impact of COVID-19 on the dentists' career plans. The variables were summarized in absolute and relative frequencies, and a binomial logistic regression analysis was carried out to evaluate the impact of COVID-19 on career plans according to the independent variables. A total of 5,370 dentists answered the survey (women: 3,878; median age: 45 years; response rate: 16.85%). Most of the dentists (96%) believed that COVID-19 infection was a risk for them and 81.96% reported that the COVID-19 pandemic had some impact on their career plans, including reducing working hours (77.96%), retiring early (26.54%) and changing their career away from dentistry (18.15%). The regression model showed that older adults (OR = 1.62; 95% CI: 1.16, 2.26), general practitioners (OR = 1.21; 95% CI: 1.02, 1.44), private practice owners (OR = 2.33; 95% CI: 1.94, 2.79), private practice associates (OR = 2.20; 95% CI: 1.84, 2.63), and those with 'very probable' risk perception (OR = 4.29; 95% CI: 1.35, 13.60) had a significantly greater chance of the pandemic having an impact on their future career plans. The pandemic has had a great impact on dentists' career plans. Dentists who are most fearful of the risk of contagion, those who are older and those who have their private practice are thinking about reducing working hours, retiring early or changing their career.

Objective: To evaluate orthodontists’ preferences in the use and timing of appliances for the correction of Class II and Class III malocclusions in growing patients and the sociodemographic factors that influence these preferences. Material and Methods: Active members of the Colombian Orthodontics Society (SCO) were invited to complete a previously validated survey on the use of Class II and Class III correctors in growing patients. Results: 180 orthodontists responded (80 male, 100 female). The appliances used most frequently in the treatment of Class II malocclusion were Planas indirect tracks (32.78%) and Twin-blocks (30.56%). Facemasks (62.22%) and Progenie plates (25%) were the most prevalent appliances used in the treatment of Class III malocclusions. Regarding treatment timing, 52% of the orthodontists stated that Class II malocclusions must be treated during late mixed dentition or early permanent dentition, 42% stated that treatment for Class III malocclusions sho-uld occur during early mixed dentition. Appliance use and treatment timing were significantly associated with sex (p= 0.034), years of practice (p= 0.025), and area of work (private clinics or public institutions), (p= 0.039). Conclusion: Twin-blocks and Facemask appliances were the preferred appliances for Class II and Class III treatment, respectively, in growing patients. Most of the orthodontists believed that Class II malocclusions must be treated during late mixed dentition and that Class III malocclusions must be treated during early mixed dentition. Sociodemographic variables are related factors that influence orthodontists’ preferences in the use of these appliances.