FACTORS INFLUENCING THE DECISION TO INITIATE ORTHODONTIC TREATMENT AND THE CHOICE OF APPLIANCE TYPE IN A LEBANESE SAMPLE DURING THE COVID-19 PANDEMIC AND THE ECONOMIC CRISIS. A CROSS-SECTIONAL STUDY.

Background: The spread of Coronavirus Disease 2019 (COVID-19) has led to a major public health issue. This study aimed to assess the factors that influence the Lebanese people in undergoing an orthodontic treatment after the outbreak of COVID-19, as well as the factors that influence their choice of orthodontic appliance type. Methods: 489 Lebanese participants (199 men and 290 women) were invited to fill a questionnaire developed on Google Forms. Eligible participants were simply Lebanese people including those who immigrated during the crisis. Dentists, dental students and foreigners were excluded from the study. The link for the questionnaire was sent to the patients via WhatsApp. It is a brief, structured 10-item questionnaire that assesses the relationship between the economic recession and the COVID-19 pandemic and the Lebanese participants’ decision to initiate orthodontic treatment and their choice of appliance type. Results: A total of 489 responses were obtained: 199 men (41%), 290 women (59%) with a mean age of 24 years ±8.4 years (age range: 13 to 64 years). Half of the participants feel anxious in consulting for an orthodontic opinion during the pandemic. Almost half of the respondents are thinking of starting orthodontic treatment after the start of COVID-19. The responses showed that most participants (71%) believe that the current economic crisis in Lebanon influences their decision to start an orthodontic treatment. Regarding the choice of the type of orthodontic appliance, a higher number of respondents choose metal braces (traditional) than other appliances. In a normal situation, the aesthetic of the appliance is the most important factor in choosing the appliance. Conclusion: The COVID-19 pandemic and the current economic crises in Lebanon had a negative impact on the financial and emotional well-being of the Lebanese people, on their decision to initiate an orthodontic treatment as well as on choosing the type of the appliance. However, despite the difficult circumstances facing the country, a big part of the respondents was not discouraged from initiating treatment

Residual Adhesive Removal Methods for Rebonding of Debonded Orthodontic Metal Brackets: Systematic Review and Meta-Analysis

Debonding of orthodontic brackets is a common occurrence during orthodontic treatment. Therefore, the best option for treating debonded brackets should be indicated. This study aimed to evaluate the bond strength of rebonded brackets after different residual adhesive removal methods. This systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Web of Science, The Cochrane Library, SciELO, Scopus, LILACS, IBECS, and BVS databases were screened up to December 2020. Bond strength comparisons were made considering the method used for removing the residual adhesive on the bracket base. A total of 12 studies were included for the meta-analysis. Four different adhesive removal methods were identified: sandblasting, laser, mechanical grinding, and direct flame. When compared with new orthodontic metallic brackets, bond strength of debonded brackets after air abrasion (p = 0.006), mechanical grinding (p = 0.007), and direct flame (p < 0.001) was significantly lower. The use of an erbium-doped yttrium aluminum garnet (Er:YAG) laser showed similar shear bond strength (SBS) values when compared with those of new orthodontic brackets (p = 0.71). The Er:YAG laser could be considered an optimal method for promoting the bond of debonded orthodontic brackets. Direct flame, mechanical grinding, or sandblasting are also suitable, obtaining clinically acceptable bond strength values

L’approche orthodontico-chirurgicale revisitée

La préparation orthodontique est la clé du succès d’une chirurgie orthognathique. Ainsi la détection et la correction des compensations dentaires favorisent la correction des décalages et déficits squelettiques. Les objectifs orthodontiques pré-chirurgicaux sont importants à définir dès le début du traitement et ne doivent pas toujours inclure le nivellement complet des arcades, la fermeture complète des espaces, ou l’intercuspidation idéale. La préparation orthodontique dicte les mouvements squelettiques qui sont possibles au moment de la chirurgie. Différents types de malocclusions présentent des compensations dentaires caractéristiques qui peuvent être identifiées et décrites. La planification appropriée, l’individualisation et la communication entre le chirurgien et l’orthodontiste sont critiques afin d’éviter certains pièges dans la préparation orthodontique

Influence of Resin Cement Thickness and Elastic Modulus on the Stress Distribution of Zirconium Dioxide Inlay-Bridge: 3D Finite Element Analysis

The mechanical properties and the thickness of the resin cement agents used for bonding inlay bridges can modify the clinical performance of the restoration such as debonding or prosthetic materials fracture. Thus, the aim of this study was to evaluate the stress distribution and the maximum strain generated by resin cements with different elastic moduli and thicknesses used to cement resin-bonded fixed partial denture (RBFPD). A three-dimensional (3D) finite element analysis (FEA) was used, and a 3D model was created based on a Cone-Beam Computed Tomography system (CBCT). The model was analyzed by the Ansys software. The model fixation occurred at the root of the abutment teeth and an axial load of 300 N was applied on the occlusal surface of the pontic. The highest stress value was observed for the Variolink 0.4 group (1.76 × 106 Pa), while the lowest was noted for the Panavia 0.2 group (1.07 × 106 Pa). Furthermore, the highest total deformation value was found for the Variolink 0.2 group (3.36 × 10−4 m), while the lowest was observed for the Panavia 0.4 group (2.33 × 10−4 m). By means of this FEA, 0.2 mm layer Panavia F2.0 seemed to exhibit a more favorable stress distribution when used for cementation of posterior zirconium-dioxide-based RBFPD. However, both studied materials possessed clinically acceptable properties