Relationship between palatally impacted canines and dimensions and morphology of sella turcica: A cone-beam computed tomography study.

INTRODUCTION: This study aimed to analyze the association of unilateral and bilateral palatal canine impaction with the dimensions and morphology of sella turcica from 3-dimensional cone-beam computed tomography (CBCT) images. METHODS: CBCT images of patients with bilateral (BPI) (n = 12; 9 female 3 male; 20.75 ± 5.88 years) and unilateral (UPI) (n = 35; 22 female 13 male; 19.28 ± 5.57 years) palatally impacted canines were compared with a control group (n = 56; 34 female 22 male; 20.82 ± 4.88 years). Linear measurements regarding sella turcica were made, and its morphologic variations were categorized. Two group comparisons were made with the Student t test or Mann-Whitney U-test, whereas one-way analysis of variance or Kruskal-Wallis tests were used for multiple group comparisons. Categorical variables were compared using the chi-square or Fisher exact test as appropriate. The binary logistic regression analyses and correlations using Spearman or Pearson correlation analyses were used to determine associations between variables (P <0.05). RESULTS: Sella diameter was significantly smaller in the BPI group compared to UPI and control groups. There was a significant association between sella diameter and BPI when compared with the control group (χ2[1] = 9.150; P = 0.008). There were no significant differences between groups in the distribution of sella turcica morphology. CONCLUSIONS: Despite the similar genetic origin of the sella turcica region and teeth, the association of palatal canine impaction with dimensions and morphology of sella turcica was weak. Both local and genetic factors might contribute to the ectopic position of the canine.

Effects of Tooth Brushing and MouthWashing on Leaching Bisphenol A Levels From an Orthodontic Adhesive: An In Vitro Study.

OBJECTIVE: To assess the levels of bisphenol A (BPA) released from an orthodontic adhesive with respect to the effects of tooth brushing and mouth washing. METHODS: Three groups, each containing fifteen adhesive samples were prepared. In Group 1, samples were polymerized according to manufacturer instructions. In Group 2, after the same polymerization protocol, each sample was brushed with a fluoride-containing toothpaste. For Group 3, samples were immersed in a mouth washing solution after polymerization. Later, all samples were placed into glass tubes containing 5 mL distilled water. High-performance liquid chromatography (HPLC) measurements were performed to assess the leaching amount of BPA. Intergroup comparison was performed by one way ANOVA test. RESULTS: Mean amounts of BPA were found to be 0.2674 µg/L, 0.2692 µg/L, and 0.2705 µg/L, respectively. Only a significant difference was found between Group 1 and 3 (P < .01), revealing higher BPA levels with the mouth washing solution. CONCLUSION: Measurable amounts of BPA release were observed in all groups of orthodontic adhesive samples, but the detected amounts were below the toxic levels. From a clinical point of view, alcohol-containing mouth washing solutions might increase the amount of leaching monomer, since alcohol is solvent of BPA.

Perception of dental students towards case-based orthodontic education.

PURPOSE: To evaluate perceptions of fifth-year dental students' towards case-based orthodontic education. METHODS: The sample population consisted of 108 final year dental students (39 men, 69 women) who volunteered to participate in the project during their orthodontic clinical internship. Patient files including extraoral, intraoral photographs, hand-wrist, panoramic and cephalometric radiographs were randomly distributed. Each group presented their evaluations after 1 week. At the end of case discussions, students were given a questionnaire regarding their perceptions of case-based education. Differences in mean scores between groups were compared by independent samples t­test. RESULTS: The response rate was 100%. The majority of students strongly agreed that their interest and ability to interpret and diagnose the orthodontic data were increased. More than 60% strongly agreed that this education had a positive effect on their attention and effective learning. More than 45% strongly agreed that their communication with colleagues was increased, and women were significantly more inclined to group work than men (p < 0.05). More than 45% declared no additional burden. CONCLUSIONS: Orthodontic case-based education was well received by final year dental students. The most noted improvement was observed in motivation, ability to comment on the diagnosis and treatment planning of orthodontic cases, without feeling an extra workload.

Frontal sinus: is it a predictor for vertical malocclusions?

The aim of the present study was to evaluate 3D frontal sinus morphology in consideration with different vertical facial developments. The study was conducted with the pre-treatment CBCT images of 87 patients, who were divided into 3 groups according to the sum of the posterior angle. The frontal sinus measurements were performed on the axial, sagittal, and coronal sections of the CBCT images. Craniofacial measurements were performed on the lateral cephalograms, obtained from the CBCT scans. Normal distribution of the data was confirmed by the Kolmogorov-Smirnov test. ANOVA, followed by post hoc Duncan tests, was used to compare the differences among the three groups. The relationships between sinus dimensions and craniofacial parameters were assessed by the Pearson's correlation coefficient (P < 0.05). The maximum anterior-posterior dimension of the frontal sinuses (0.017), the width of the right (0.020) and left (0.041) frontal sinuses, and the anterior-posterior dimension of the left (0.038) frontal sinus were significantly smaller in the hyperdivergent group compared to hypodivergent group. There was no significant difference between groups in terms of the height of the frontal sinuses. Significant correlation was noted between the maximum anterior-posterior dimension of the frontal sinus and SN-PP, N-Me, N-ANS, SN-GoGn, Post. sum, and Jarabak's ratio. No significant correlation between the height of the frontal sinuses and the craniofacial measurements was found. Individuals with vertical growth pattern presented decreased anterior-posterior dimension of the frontal sinuses, revealing significant correlations with vertical craniofacial parameters.

Maxillary posterior intrusion with corticotomy-assisted approaches with zygomatic anchorage-a finite element stress analysis.

BACKGROUND: Anterior open bite is one of the most difficult malocclusions to treat and maintain in orthodontics. An effective treatment approach to correct anterior open bite is the intrusion of maxillary posterior teeth. The aim of this study was to evaluate the effects of corticotomy-assisted posterior maxillary intrusion with zygomatic anchorage by using finite element stress analysis. METHODS: An acrylic bite block on the posterior teeth including two transpalatal arches were modeled and 1.96 N intrusive force was loaded. Three scenarios were set, first with no subapical corticotomy, second with buccal, and third with both buccal and palatal corticotomies. The stress distributions along the cortical, cancellous bone surfaces, and dental structures were assessed by finite element stress analysis. RESULTS: Stress distributions over cortical and cancellous bones were commonly located at the inferior curvature of the zygomatic buttress area and posterior teeth for all scenarios. Stress values above the apices of anchor teeth were decreased for both corticotomy scenarios. Increased stress distributions were observed in cancellous bone around corticotomy regions. Despite the acrylic appliance and transpalatal arches, the stresses along the posterior teeth were not uniform. The apical third of the first molar mesiobuccal apex showed the highest stress values in all scenarios. CONCLUSIONS: Corticotomy-assistance effected biomechanical responses of dentoalveolar structures during maxillary posterior intrusion. There was no apparent difference for the stress levels of the root apices between corticotomy scenarios, pointing out that only buccal corticotomy may be a better option in corticotomy-assisted maxillary intrusion.

Effects of reverse headgear on pharyngeal airway in patients with different vertical craniofacial features.

The aim of this study was to investigate the effects of reverse headgear (RH) on pharyngeal airway morphology in two groups of Class III patients with different vertical craniofacial features in comparison with an untreated Class III group. Seventeen subjects (9 males, 8 females; mean age 11.3 ± 0.98 years) with optimum vertical growth and 17 subjects (10 males, 7 females, mean age 11.5 ± 1.1 years) with a vertical growth pattern treated with a removable intra-oral appliance and a Delaire type facemask were included. An untreated Class III control group of 11 subjects (8 males, 3 females, mean age 9.1 ± 1.1 years) was included to compare the treated groups. The paired t-test for intragroup and one-way ANOVA for intergroup comparisons were performed. The relationships between changes in the craniofacial morphology and airway were assessed by Spearman correlation analysis. The airway dimensions at the adenoid side and soft palate were increased in the treatment groups compared to the control group (p < 0.05). The nasopharyngeal area demonstrated a significant difference in normodivergent and control subjects (p < 0.05). No significant difference was found in the airway morphology due to different vertical features. The effect of RH treatment on the sagittal airway dimensions revealed no significant difference between different vertical craniofacial features in the short term.

Craniofacial and pharyngeal airway morphology in patients with acromegaly.

OBJECTIVE: The aim of this study was to assess differences in craniofacial characteristics, upper spine and pharyngeal airway morphology in patients with acromegaly compared with healthy individuals. MATERIALS AND METHODS: Twenty-one patients with acromegaly were compared with 22 controls by linear and angular measurements on cephalograms. The differences between the mean values of cephalometric parameters were analyzed with Mann-Whitney U-test. RESULTS: With respect to controls, anterior (p<0.05), middle (p<0.01) and posterior (p<0.05) cranial base lengths were increased, sella turcica was enlarged (p<0.001) and upper spine morphology demonstrated differences in the height of atlas (p<0.01) and axis (p<0.05) in patients with acromegaly. Craniofacial changes were predominantly found in the frontal bone (p<0.01) and the mandible (p<0.05). As for the airway, patients with acromegaly exhibited diminished dimensions at nasal (p<0.001), uvular (p<0.01), mandibular (p<0.01) pharyngeal levels and at the narrowest point of the pharyngeal airway space (p<0.001) compared to healthy controls. Soft palate width was significantly higher (p<0.001) and the hyoid bone was more vertically positioned (p<0.01) in patients with acromegaly. CONCLUSIONS: Current results point to the importance of the reduced airway dimensions and that dentists and/or orthodontists should be aware of the cranial or dental abnormalities in patients with acromegaly.

The effect of drill-free and drilling methods on the stability of mini-implants under early orthodontic loading in adolescent patients.

The aim of this study was to compare the stability of mini-implants using drill-free and drilling methods, both before and after early force loading. Sixty-two adolescent patients (24 males and 38 females, mean age 15.7 ± 4.2 years) were randomly assigned to three groups and 112 titanium mini-implants were placed between the upper first molars and second premolars to achieve molar distalization. Groups I (n = 22) and II (n = 20) received pilot drilling with diameters of 1.1 and 0.9 mm, respectively, while the drill-free method was used in group III (n = 20). Distalization forces of up to 200 g were applied with nickel-titanium (NiTi) open coil springs. The Z-test was used for statistical analyses to compare the success rates of the groups with each other. The overall success rate was 77.7 per cent. There was no significant difference between groups I and II either before or after loading. Significant differences were found between groups I and III (P = 0.0002) and between groups II and III (P = 0.045) both before and after loading. Mini-implants using the drill-free method provided the highest success rate before orthodontic force application and also maintained their stability after early loading for 1 month during orthodontic treatment. Smaller drill diameters can contribute to clinical stability of mini-implants in the short-term, however long-term evaluations are needed to clarify the stability of temporary skeletal anchorage devices throughout orthodontic loading.