Doina Chioran

Background and Objectives: This study aimed to identify osseous and dental mandibular landmarks that consistently indicate the location of the mental foramen, the primary reference for the mental–incisive trunk block. Materials and Methods: Computed Tomography (CT) scans of the mandibles of 100 patients from a Romanian population (N = 100) were retrospectively analyzed to measure the following: distances from the mental foramen to the basal border of the mandible, alveolar process/crest, and midline, as well as the position of the foramen relative to the lower premolars. These measurements were correlated with patients’ age (divided into three groups: 18–30 years, 30–60 years, >60 years) and gender. Results: The mental foramen was found to be closer to the alveolar crest (13.3 mm with SD = 3.3 in males and 10.7 mm with SD = 4.4 in females, overall mean = 12.3 mm, SD = 4.0) (p = 0.001) than to the inferior border of the mandible (14.3 mm with SD = 1.8 in males and 12.9 mm with SD = 1.6 in females, overall mean = 13.7 mm, SD = 1.9) (p < 0.001). In addition, the foramen was most frequently located adjacent to the second premolar (27.0%) rather than between the premolars (20.0%) and at a distance of ≃2.5 cm lateral to the midline (overall mean = 25.2 mm, SD = 3.5) (p = 0.034). Conclusions: Following the measurements performed, the mental foramen was identified as being closer to the alveolar crest in the vertical direction, at a distance of approximately 2.5 cm lateral to the midline, and most frequently located at the level of the second lower premolar.

Background/Objectives: The uprighting of mesially tipped mandibular second molars following first molar loss is a complex surgical and orthodontic challenge. Conventional methods often result in reciprocal anchorage loss. Mini-implants (MIs) have emerged as essential temporary anchorage devices (TADs) that provide absolute anchorage and enable more predictable tooth movements. Methods: Numerical simulations were performed to evaluate the forces required for mandibular second molar uprighting under two conditions: first, only with the second molar present, and second, with both the second and the third molars present. Although the periodontal ligament exhibits nonlinear and viscoelastic behavior in vivo, a linear elastic approximation was adopted to allow for a reliable evaluation of comparative stress distribution and initial displacement patterns within the scope of this exploratory biomechanical study. Stress distribution in the roots, periodontal ligament, and alveolar bone was assessed for each scenario. Two three-dimensional (3D) models of the left mandibular segment were created from scans of a human mandible and its teeth. The first model included the canine, the first and second premolars, and the second molar. A second model additionally incorporated the third molar. A retromolar MI was placed in both models. Molar uprighting was simulated using a spring connecting the implant to a button bonded on the mesial surface of the second molar. A force of 200 g was applied because in clinical orthodontic practice, forces that exceed approximately 2 N may cause pain or undesirable tooth mobility. Displacements along the X, Y, and Z axes, as well as regions of peak stress, were analyzed. Results: Model 1 showed maximum displacements at the furcation/mid-root, distal root apex, and distal crown, with von Mises stresses of 0.470 to 0.371 MPa. In Model 2, peak displacements occurred at the mesial root and crown, with stresses of 0.185 and 0.149 MPa, respectively. The magnitude of displacements was in the order of 10⁻⁵ mm. Such values represent initial mechanical responses rather than clinically observable tooth movements. However, the differences between models (e.g., the stress reduction) are expected to be clinically meaningful. Conclusions: Since clinical measurements regarding the stress distribution on teeth and surrounding tissues during orthodontic molar uprighting movements are impossible to perform, the finite element method (FEM) can offer insight into these aspects. The presence of the third molar significantly modulates the biomechanics of second molar uprighting via retromolar MIs. When the third molar is present, the second molar exhibits a reduced tendency for deformation during distalization, although this leads to a slower displacement. This FEM provides biomechanical insights but does not support direct clinical decision-making. The present findings should be viewed as theoretical biomechanical tendencies that require confirmation through clinical, experimental, and longitudinal studies before translation into clinical practice.

Background: The use of vasoconstrictors in dental anesthesia during pregnancy raises clinical concerns due to their potential effects on uteroplacental blood flow and fetal well-being. Despite widespread use, the safety profiles of agents such as epinephrine, levonordefrin, and felypressin remain insufficiently reviewed, particularly in isolation from local anesthetics. Methods: A systematic literature search was conducted using PubMed (MEDLINE) for studies published between January 2000 and May 2025, following PRISMA 2020 guidelines. Included studies assessed the use, pharmacokinetics, or outcomes of vasoconstrictor agents used in dental procedures during pregnancy. Articles were selected based on predefined inclusion criteria and synthesized narratively. Results: Out of 95 screened records, only six narrative reviews and three clinical guidelines met eligibility criteria. Epinephrine was the most frequently described agent, generally regarded as safe at low dental doses (1:100,000–1:200,000) when properly administered. Levonordefrin showed insufficient safety data and was associated with potential uterine vasoconstriction. Felypressin was contraindicated due to its oxytocic properties and high risk of inducing uterine contractions. Conclusions: Among vasoconstrictors, epinephrine remains the only agent with an acceptable safety profile in pregnancy when used correctly. Levonordefrin lacks adequate evidence, and felypressin poses clear risks. Until further clinical trials are available, individualized risk assessment and adherence to obstetric and dental guidelines are critical for ensuring maternal and fetal safety.