Evaluation of the pattern of fracture formation from trauma to the human mandible with finite element analysis. Part 2: The corpus and the angle regions.

BACKGROUND/AIMS: Although the mandible is the largest and strongest bone of the facial skeleton, it is frequently broken. The fracture location in the mandible depends on the biomechanical features, direction and angle of the trauma, and masticatory muscles. This study aimed to evaluate the stresses caused by trauma to the corpus and angle regions from different angles. MATERIALS AND METHODS: After computer-based mandible models were created using finite element analysis, a force of 2000 Newton(N) was simulated with the mouth open or closed to the corpus and the angle. To the corpus: at 90° (Model 1) in the lateromedial direction, 45° (Model 2) in the lateromedial-inferosuperior direction, and 90° (Model 3) in the inferosuperior direction. To angle: 90° (Model 4) in the lateromedial direction and 45° (Model 5) in the lateromedial-inferosuperior direction. The resulting stress intensity was assessed using FEA. RESULTS: Following the simulated forces, the maximum stress in the mandible occurred in the condylar region, except in Model 3 (Left(L)Corpus2[36 megapascals(MPa)]) in the mouth-closed condition. After traumas in Model 1 (open-mouth: LCondyle2[547 MPa]) and Model 4 (closed-mouth: LCondyle2[607 MPa]), higher stress values occurred in the condyle. In the mouth open-closed state, there was no significant stress change in the condyle region in Model 1 (open-mouth: LCondyle2[547 MPa], closed-mouth:LCondyle2[546 MPa]) or in Model 2 (open mouth: Right(R)Condyle2[431 MPa], closed-mouth:LCondyle2[439 MPa]). In Model 3, lower stress values occurred in the closed-mouth rather than the open-mouth (LCondyle1[167 MPa]) state. In Models 4 and 5, the stress values increased in the mouth-closed condition compared with the mouth-open condition. CONCLUSIONS: Stress in the mandible is affected by the location of the trauma and the angle of incidence of the blow. In trauma to both the corpus and the angle, the most common area to be fractured is the condyle.

Evaluation of the pattern of fracture formation from trauma to the human mandible with finite element analysis. Part 1: Symphysis region.

BACKGROUND/AIM: The mandible is the largest, strongest bone in the maxillofacial region. When a fracture occurs in the mandible, its location depends on several factors: the direction of the trauma, the angle of the trauma, masticatory muscles and the quality of the bone. The aim of this study was to evaluate the stresses caused by trauma to the symphysis region from different angles. MATERIALS AND METHODS: Computer-based mandible models were created, and a 2000 N force was applied to the symphysis at three different angles using finite element analysis. Six trauma situations were simulated with the mouth open or closed. Forces were applied to the symphysis at 90° (Model 1) in the anteroposterior direction, 45° (Model 2) in the anteroposterior-inferosuperior direction and 90° (Model 3) in the inferosuperior direction, when the mouth was open or closed. The resulting stress intensity was assessed using finite element analysis. RESULTS: As a result of trauma applied to the symphysis region, maximum stresses were found where the impact originated and at the condyle region (Model 2, open mouth: condyle 1 [1172 MPa]). The open mouth position caused higher stress values than the closed mouth position (Model 2, open mouth: condyle 1 [1172 MPa]; closed mouth: symphysis 4 [82 MPa]). The Model 2, open-mouth state (Model 2, open mouth: condyle 1 [1172 MPa]) sustained higher stresses than all the other models. CONCLUSION: The stress values in the mandible were affected by the force applied to the symphysis region, the angle of impact arrival and the open or closed state of the mouth. Keeping the mouth closed at the time of trauma reduced the stress value. A closed mouth during trauma directed at the symphysis reduced the possibility of mandible fractures.

Olfactory Fossa Evaluation as a Maxillary Sinus Development Using Cone Beam Computed Tomography.

In our study, we aimed to evaluate the risk of skull base perforation during endoscopic sinus surgery in individuals with hypoplasic maxillary sinuses using Cone Beam Computed Tomography (CBCT). We included 52 patients with bilateral maxillary sinus hypoplasia and 52 patients with normal maxillary sinus in the study. Reviewing paranasal CBCT scans, we noted the olfactory fossa depths and lateral lamella lengths of all the groups and compared between the hypoplasia groups and the control group. Compared the maxillary hypoplasia sinus individuals with the control group, both the olfactory fossa depths and the lateral lamina length were different in the maxillary hypoplasic individuals. In individuals with hypoplasic maxillary sinus, the olfactory fossa depth and the lateral lamina length values are higher, which increases the risk of complications in endoscopic sinus surgery.

Evaluation of metal concentrations in hair and nails after dental implant placement.

STATEMENT OF PROBLEM: The accumulation of the elements contained in Ti6Al4V, the mostly used titanium alloy for dental implants, in epithelial extensions requires investigation. Studies evaluating the metals in dental implants in the hair and nails of patients with dental implants are lacking. PURPOSE: The purpose of this clinical research was to measure the levels of titanium (Ti), aluminum (Al), and vanadium (V) in the hair and nails of patients treated with grade 5 Ti alloy dental implants. MATERIAL AND METHODS: Ti, Al, and V elemental levels in the hair and nail samples of 33 participants treated with grade 5 Ti alloy dental implants were measured by using an inductively coupled plasma mass spectrometer. RESULTS: The results revealed a statistically significant increase in the amount of Ti in nail samples after implant surgery (P=.01), but no statistically significant increases in the amounts of Al or V in nail samples (P=.48, P=.645). In hair samples, the increase in Ti, Al, and V was not statistically significant (P=.728, P=.221, P=.376). The correlation between the amount of change in the elements in implants and the contact areas was weak for hair (Al, r=0.114; Ti, r=0.361; V, r=0.377) and for nails (Al, r=0.127; Ti, r=0.116; V, r=0.058). CONCLUSIONS: After the placement of dental implants made of grade 5 Ti alloy, minimal Al and V accumulated in hair and nails.

Morphometric Analysis of Cleft Lip Palate and Prognathic Mandibles in Relation to Mandibular Canal Course.

INTRODUCTION: This study aimed to evaluate the mandibular canal course in individuals with cleft lip palate (CLP) and mandibular prognathism in terms of the sagittal split-ramus osteotomy using cone-beam computed tomography. MATERIALS AND METHODS: Individuals with CLP older than 16 years of age and planned to undergo Le fort I + SSR osteotomies and those with class III occlusion planned to undergo Le fort I + SSR osteotomies were included. The measurements on the cleft side of CLP patients were compared with both their noncleft sides and those with class III occlusion. The course of the inferior alveolar nerve and its position in the mandible were evaluated starting from the mandibular foramen, the first entrance to the mandible, to the mental foramen, the exit from the mandible. RESULTS: The distance between the mandibular canal and the buccal surface of the mandible (B3) on the plane tangent to the distal of the mandibular first molar and perpendicular to the occlusal plane was found to be greater in individuals with CLP (P = 0.011). Buccal cortex thickness (C4) at the level of the mandibular canal on the plane tangent to the distal of the mandibular second molar and perpendicular to the occlusal plane was found to be lower in individuals with CLP (P = 0.021). CONCLUSIONS: The buccal cortex thickness of the mandible corpus and the distance of the mandibular canal to the buccal surface is different in patients with CLP compared to class III individuals' posterior to the mandible. Surgeons should take these differences into consideration during mandibular osteotomy.

Evaluation of Lefort I Osteotomy Line and Pterygomaxillary Junction Region in Patients With Cleft Lip and Palate.

OBJECTIVE: This study aimed to evaluate the Le Fort I osteotomy line and pterygomaxillary junction via cone-beam computed tomography in individuals with cleft lip and palate (CLP). DESIGN: Retrospective study. Patients and Methods: The study included individuals older than 16 years with CLP, who were scheduled for repositioning of the maxilla by Le Fort I osteotomy, and those with class III malocclusion with maxillary hypoplasia, who were scheduled for Le Fort I osteotomy. The measurements made in the area of the cleft of individuals with CLP were compared with both the side with no cleft and those with class III malocclusion with maxillary hypoplasia. A total of 11 measurements were made on the axial section parallel to the Frankfurt Horizontal plane, corresponding to the lower 1/5 of the distance between the infraorbital foramen and the anterior nasal spine. RESULTS: There were significant differences both in the comparisons made between the individuals with CLP and those without CLP in terms of the canal-anterior alveolar crest (G) and sinus-anterior alveolar crest (L) measurements (P < .05). The mean measurement values showed that the measurement results were higher in individuals with CLP in general. CONCLUSION: In conclusion, we believe that there might be difficulties both in osteotomy and down fracture stages during Le Fort I osteotomies performed in individuals with CLP.

Treatment of the Patient With Crouzon Syndrome With Orthognathic Surgery.

Crouzon syndrome is a genetic disease that is transferred by autosomal dominant inheritance. Patients with this syndrome have craniosynostosis, hypertelorism, orbital proptosis, mid-face hypoplasia, mandibular prognathism, and concave facial profile. A number of surgical treatments are used to improve facial contours, and to correct dental and maxillary relationships. Orthognathic surgery is routinely used in the treatment of these patients. We present a female patient with Crouzon syndrome treated with Le Fort I and bilateral sagittal split osteotomy. Previously, surgically assisted rapid maxillary expansion (SARME) surgery was performed to the patient by separating the pterygomaxillary junction under general anesthesia. Down fracture was performed during the Le Fort I osteotomy without the need to separate the pterygomaxillary junction again. The facial appearance was improved with bilateral sagittal split osteotomy, and skeletal malocclusion between the jaws was treated.

Maxillary Osteomyelitis Caused by Kocuria Species in a Patient Who Is on Long-Term Uncontrolled Use of Methylprednisolone.

Uncontrolled use of medicines bring with it serious health problems. Long-term and uncontrolled use of steroids, without the supervision of a healthcare professional, may cause unexpected infections due to immunosuppression. The authors present a patient with maxillary osteomyelitis caused by Kocuria species in a 41-year-old male who has been receiving methylprednisolone without control for 1.5 years.