Strategic treatment for a patient with missing lateral incisor and first molar accompanied by posterior scissor bite and an impacted premolar.

Managing orthodontic treatment for adults with missing permanent teeth can be intricate, especially when dealing with a posterior scissor bite and an impacted tooth. This case report presents successful treatment of a female patient with dental and skeletal Class II malocclusion, high mandibular plane angle, missing maxillary left lateral incisor and mandibular right first molar, as well as right posterior scissor bite, and a deeply impacted mandibular left second premolar. In the maxilla, the right second molar and right lateral incisor were strategically extracted to eliminate the scissor bite and enhance frontal esthetic balance. In the mandible, the edentulous space caused by early loss of the first molar was successfully closed and the impacted second premolar was guided into its proper position after surgical exposure. Finally, symmetric frontal esthetics, well-aligned dentition with ideal intercuspation and an improved profile were achieved, which remained stable in the 17 month follow-up.

Constructing Mal-Efferocytic Macrophage Model and Its Atherosclerotic Spheroids and Rat Model for Therapeutic Evaluation.

Efferocytosis, responsible for apoptotic cell clearance, is an essential factor against atherosclerosis. It is reported that efferocytosis is severely impaired in fibroatheroma, especially in vulnerable thin cap fibroatheroma. However, there is a shortage of studies on efferocytosis defects in cell and animal models. Here, the impacts of oxidized low density lipoprotein (ox-LDL) and glut 1 inhibitor (STF31) on efferocytosis of macrophages are studied, and an evaluation system is constructed. Through regulating the cell ratios and stimulus, three types of atherosclerotic spheroids are fabricated, and a necrotic core emerges with surrounding apoptotic cells. Rat models present a similar phenomenon in that substantial apoptotic cells are uncleared in time in vulnerable plaque, and the model period is shortened to 7 weeks. Mechanism studies reveal that ox-LDL, through mRNA and miRNA modulation, downregulates efferocytosis receptor (PPARγ/LXRα/MerTK), internalization molecule (SLC29a1), and upregulates the competitive receptor CD300a that inhibits efferocytosis receptor-ligand binding process. The foam cell differentiation has also confirmed that CD36 and Lp-PLA2 levels are significantly elevated, and macrophages present an interesting transition into prothrombic phenotype. Collectively, the atherosclerotic models featured by efferocytosis defect provide a comprehensive platform to evaluate the efficacy of medicine and biomaterials for atherosclerosis treatment.

Subjective and objective analysis of orthodontic expert consensus on the assessment of orthodontic treatment outcomes.

OBJECTIVE: The objective of the study was to explore and validate the consensus of orthodontic experts on the assessment of orthodontic treatment outcomes based on subjective and objective analysis. MATERIALS AND METHODS: The research consisted of two parts: the exploration and verification of expert consensus. First, a sample of 108 cases randomly selected from six dental schools in China were evaluated by 69 orthodontic experts and measured by researchers based on post-treatment study casts and lateral cephalograms, respectively. Then, through statistical analysis, the objective indicators significantly correlated with experts' subjective evaluations were selected, their weights were determined, and the critical values of satisfactory, acceptable and unacceptable grades were screened. Subsequently, another sample of 72 cases were evaluated by another 36 orthodontic experts, and the subjective evaluation results were compared with the objective measurement results. RESULTS: There were six model indicators and seven cephalometric indicators being significantly correlated with the experts' subjective evaluations, including occlusal contact, overjet, midline, interproximal contact, alignment, occlusal relationship, L1/NB, ANB, SN/OP, U1/SN, LL-EP, Cm-Sn-UL and Ns-Prn-Pos, with a cumulative R2 of 0.704. In the verification part, the correlation coefficient between the 36 experts' subjective scores and objective regression scores was 0.716 (P < .001); the correlation coefficient between the 36 experts' subjective grades and objective grades was 0.757 (P < .001). CONCLUSIONS: Orthodontic experts had good consistency in the subjective evaluation of the combined records of post-treatment study casts and lateral cephalograms. The objective indicators selected from subjective and objective analysis had good reliability and validity and could further improve the existing occlusal indices.

Accuracy of integration of dental cast and cephalograms compared with cone-beam computed tomography: a comparative study.

This study proposes a method that integrates maxillary dental cast and cephalograms and evaluates its accuracy compared with cone-beam computed tomography (CBCT) scans. The study sample comprised 20 adult patients with records of dental casts, cephalograms, and craniofacial CBCT scans. The maxillary dental cast was integrated with lateral and frontal cephalograms based on best-fit registration of palatal and dental outline curves from dental cast with cephalogram tracings. Linear measurement was conducted to assess the intra- and inter-examiner reproducibility of the proposed integration method using intraclass correlation coefficients; linear and angular measurements were conducted to assess its accuracy with CBCT scans as a standard reference. Paired t test, one sample t test, and mean ± standard deviation of the absolute value of difference were used to compare the integrated images and CBCT. The integration method showed good intra- and inter-examiner reproducibility (intraclass correlation coefficients > 0.98). The differences in linear and angular measurements between the integrated images and CBCT were not statistically significant but with a large deviation. When absolute value of difference was computed, the linear distance error was 0.51 ± 0.34 mm, the tooth point coordinate errors in X, Y and Z axes were 0.22 ± 0.22, 0.38 ± 0.32 and 0.21 ± 0.21 mm, respectively; the angular error in pitch, roll and yaw of the dental cast was 0.82 ± 0.51, 0.92 ± 0.59 and 0.80 ± 0.41 degree, respectively. The proposed method for integration of dental cast and cephalograms showed good reproducibility and acceptable accuracy compared with CBCT. It could be helpful for researchers to study three-dimensional tooth growth changes using the existing craniofacial growth data especially cephalograms.

Exosome-Loaded Pro-efferocytic Vascular Stent with Lp-PLA2-Triggered Release for Preventing In-Stent Restenosis.

The efferocytosis defect is regarded as a pivotal event of atherosclerosis. The failure to clear apoptotic cells in atherosclerotic plaques under vascular stents causes a failure to resolve the inflammation underneath. However, efferocytosis repair is still confined to nonstenting therapeutics. Here, we identified a pro-efferocytotic agent and accordingly developed a bioresponsive pro-efferocytotic vascular stent aimed for poststenting healing. Exosomes derived from mesenchymal stem cells were found to be able to regulate efferocytosis via SLC2a1, STAT3/RAC1, and CD300a pathways and modulate foam cell formation processes through a CD36-mediated pathway. Pro-efferocytotic exosomes were encapsulated into liposome-based multivesicular chambers and grafted onto vascular stents. The multivesicular vesicles were able to release exosomes under the Lp-PLA2 environment. Compared to bare metal stents, exosome-stents in the presence of Lp-PLA2 enhanced the ratio of apoptotic cell clearance and reduced the neointimal thickness in the mal-efferocytotic rat model. Overall, we identified a pro-efferocytic agent─exosomes that are able to regulate target cells via multiple signaling pathways and are good candidates to serve complex pathological environments, and this bioresponsive pro-efferocytotic vascular stent is an attractive approach for prevention of poststenting complications.

Comparison of achieved and predicted crown movement in adults after 4 first premolar extraction treatment with Invisalign.

INTRODUCTION: In this study, we compared achieved and predicted crown movements of maxillary and mandibular first molars, canines, and central incisors in adults after 4 first premolar extraction treatment with Invisalign. METHODS: Seventeen adult patients who received 4 first premolar extraction treatment with Invisalign and completed the first series of aligners were included. Superimposition of pretreatment and actual posttreatment dental models was acquired using registrations of pretreatment and posttreatment craniofacial models on the basis of bone surfaces and registrations of craniofacial and dental models on the basis of dental crown surfaces, respectively. Superimposition of pretreatment and predicted posttreatment models was acquired from ClinCheck software. Achieved and predicted 3-dimensional crown movements of maxillary and mandibular first molars, canines, and central incisors were then compared using the paired t test. RESULTS: Relative to predicted changes, first molars achieved greater mesial displacement, mesial tipping, and buccal inclination in both the maxilla and mandible, greater intrusion in the maxilla, and greater mesial-lingual rotation and less constriction in the mandible. Canines achieved greater distal tipping in both the maxilla and mandible, less retraction in the maxilla, and greater lingual inclination and extrusion in the mandible. Central incisors achieved greater distal tipping and lingual inclination and extrusion in both the maxilla and mandible and less retraction in the maxilla. CONCLUSIONS: Tooth crown movements were not fully achieved as predicted following Invisalign treatment. Differences focused on mesial tipping, buccal inclination, mesial displacement, and intrusion of the first molars, as well as distal tipping, lingual inclination, insufficient retraction, and intrusion of the canines and central incisors.

Analysis of correlation of 3-dimensional lip vermilion morphology and dentoskeletal forms in young Chinese adults on the basis of sex and skeletal patterns.

INTRODUCTION: The objective of this research was to evaluate the correlation between 3-dimensional (3D) lip vermilion (LV) morphology and skeletal patterns as well as incisor measurements in young Chinese adults. METHODS: In all, 240 young adults were enrolled; these included 80 patients each with skeletal Class I, Class II, and Class III malocclusions, respectively. Each sagittal skeletal pattern included 40 male and 40 female subjects. Twenty-two 3D LV measurements were obtained from 3D facial scans. Skeletal and incisor measurements were evaluated on lateral cephalograms. Correlation and regression analysis were performed between soft and hard tissue measurements. RESULTS: Six of 22 LV measurements showed significant differences between male and female subjects. The 3D LV morphology showed significant differences with respect to different skeletal patterns and sex. Adults with skeletal Class III malocclusion tended to have thinner upper vermilion and fuller lower vermilion than subjects with skeletal Class II and III malocclusion. The mandibular plane angle negatively correlated with the upper-lower vermilion midsagittal curve length and surface area ratio in adults with skeletal Class I and II malocclusion, yet the vertical facial skeletal type showed no correlation in adults with skeletal Class III malocclusion. The vermilion angle, central bow angle, vermilion height, vermilion midsagittal curve length, vermilion height and width ratio, and vermilion surface area showed a significant correlation with incisor measurements. Regression analysis found that the ANB angle was an important factor affecting the upper and lower vermilion midsagittal curve length and surface area ratio. Further, the vermilion height and height and width ratio were closely correlated with the interincisal (U1/L1) angle, whereas the central bow angle was closely correlated with the maxillary incisor torque. CONCLUSIONS: Most LV morphology variables were correlated to skeletal patterns and incisor measurements. Skeletal Class III malocclusion showed significant differences in vermilion morphology. Both the sagittal and vertical skeletal pattern have effects on vermilion proportion. The incisor torque was closely correlated to vermilion shape and central bow angle and might influence the vermilion esthetics. However, the proportion of the upper and lower vermilion was mainly affected by the ANB angle.

Accuracy and reliability of maxillary digital model (MDM) superimposition in evaluating teeth movement in adults compared with CBCT maxillary superimposition.

Superimposition of 3D maxillary digital dental models of different time points based on palatal vault region has been used to evaluate tooth movement during orthodontic treatment. This study evaluated the accuracy and reliability of 3D maxillary digital model (MDM) superimposition in adults by comparing it with CBCT maxillary superimposition. In CBCT maxillary superimposition, voxel-based superimposition was firstly conducted, and MDMs were matched with corresponding CBCT models (CBCT-MDM superimposition). MDM superimposition (palatal vault regional superimposition) were performed on another pair of pre- and posttreatment MDMs. The position and orientation of upper first molars (U6s) and upper central incisors (U1s) on the posttreatment MDMs were compared to assess the accuracy of the MDM superimposition methods. The reliability was validated in both MDM superimposition and CBCT maxillary superimposition. In terms of accuracy, the average linear deviations in U6 and U1 positions were less than ± 0.3 mm, the average angular deviations of U6s and U1s were less than ± 0.2°, both have no significant difference from zero. The ICCs for MDM superimposition ranged from 0.85 to 0.99. The ICCs for CBCT-MDM superimposition were larger than 0.99 in all items. MDM superimposition was an efficient, accurate and reliable method for evaluating teeth movement in adults, although its reliability is slightly lower than CBCT maxillary superimposition.

Three-dimensional changes in lip vermilion morphology of adult female patients after extraction and non-extraction orthodontic treatment.

OBJECTIVE: To investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes. METHODS: Forty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms. RESULTS: There were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area. CONCLUSIONS: Extraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

Comparison of achieved and predicted tooth movement of maxillary first molars and central incisors: First premolar extraction treatment with Invisalign.

OBJECTIVES: To compare achieved and predicted tooth movements of maxillary first molars and central incisors in first premolar extraction cases treated with Invisalign. MATERIALS AND METHODS: The present study included 30 patients who received maxillary first premolar extraction treatment with Invisalign. The actual posttreatment model was registered with the pretreatment model on the palatal stable region and superimposed with the virtual posttreatment model. Achieved and predicted tooth movements of maxillary first molars and central incisors were compared using paired t-test. Linear mixed-effect model analyses were used to explore the influence of age (adolescents vs adults), attachment (G6-optimized vs 3-mm vertical, 3-mm horizontal, and 5-mm horizontal), and initial crowding on the differences between predicted and achieved tooth movement (DPATM). RESULTS: First molars achieved greater mesial tipping, mesial translation, and intrusion than predicted. Central incisors achieved less retraction and greater lingual crown torque and extrusion than predicted. Adolescents showed greater DPATM in the mesiodistal translation of first molars and labiolingual translation of central incisors and smaller DPATM in the occlusogingival translation of the first molars and crown torque of the central incisors than adults. The 3-mm vertical attachment group showed greater DPATM in the mesiodistal translation of the first molars vs the G6-optimized attachment group. Initial crowding had an inverse correlation with DPATM in angulation and mesiodistal translation of the first molars. CONCLUSIONS: First molar anchorage control and central incisor retraction were not fully achieved as predicted in first premolar extraction treatment with Invisalign. Age, attachment, and initial crowding affected the differences between predicted and achieved tooth movement.

Changes in buccal facial depth of female patients after extraction and nonextraction orthodontic treatments: A preliminary study.

OBJECTIVE: This study was performed to investigate buccal facial depth (BFD) changes after extraction and nonextraction orthodontic treatments in post-adolescent and adult female patients, and to explore possible influencing factors. METHODS: Twelve and nine female patients were enrolled in the extraction and nonextraction groups, respectively. Changes in BFD in the defined buccal region and six transverse and two coronal measuring planes were measured after registering pretreatment and posttreatment three-dimensional facial scans. Changes in posterior dentoalveolar arch widths were also measured. Treatment duration, changes in body mass index (BMI), and cephalometric variables were compared between the groups. RESULTS: BFD in the buccal region decreased by approximately 1.45 mm in the extraction group, but no significant change was observed in the nonextraction group. In the extraction group, the decrease in BFD was identical between the two coronal measuring planes, whereas this differed among the six transverse measuring planes. Posterior dentoalveolar arch widths decreased in the extraction group, whereas these increased at the second premolar level in the nonextraction group. The treatment duration of the extraction group was twice that of the nonextraction group. No differences were found in BMI and Frankfort horizontal-mandibular plane angle changes between the groups. BFD changes in the buccal region moderately correlated with treatment duration and dental arch width change. CONCLUSIONS: BFD decreased in adult female patients undergoing extraction, and this may be influenced by the long treatment duration and constriction of dentoalveolar arch width. However, nonextraction treatment did not significantly alter BFD.

A novel method for prediction of dynamic smiling expressions after orthodontic treatment: a case report.

Smile esthetics has become increasingly important for orthodontic patients, thus prediction of post-treatment smile is necessary for a perfect treatment plan. In this study, with a combination of three-dimensional craniofacial data from the cone beam computed tomography and color-encoded structured light system, a novel method for smile prediction was proposed based on facial expression transfer, in which dynamic facial expression was interpreted as a matrix of facial depth changes. Data extracted from the pre-treatment smile expression record were applied to the post-treatment static model to realize expression transfer. Therefore smile esthetics of the patient after treatment could be evaluated in pre-treatment planning procedure. The positive and negative mean values of error for prediction accuracy were 0.9 and - 1.1 mm respectively, with the standard deviation of ± 1.5 mm, which is clinically acceptable. Further studies would be conducted to reduce the prediction error from both the static and dynamic sides as well as to explore automatically combined prediction from the two sides.

Three-dimensional modeling of an individualized functional masticatory system and bite force analysis with an orthodontic bite plate.

PURPOSE: Orthodontic tooth movement is affected by bite forces generated from the masticatory system. This study aims to study three-dimensional (3D) modeling of the individualized functional masticatory system and explore its application in orthodontics. METHODS: An individualized masticatory system model containing the craniomaxilla, mandible, 4 pairs of primary masticatory muscles and complete dentition, including roots and precise dental crowns, was developed using 3D images from spiral computed tomography and digital casts. By registering global coordinates and using data transformation, individual movement data for mandibular opening, lateral excursion and protrusion were recorded with an Arcus Digma system and applied to this model to simulate the functional movements of the mandible. Using the finite element method, deformations and displacement of the masticatory muscles were simulated along with the mandibular movements. Under individualized muscle loading, the bite forces of the lower incisors with the orthodontic bite plate were analyzed. RESULTS: Individualized mandibular movements were simulated, and the performance of the masticatory muscles along with the mandibular movements was measured. The bite force generated on the lower incisors with different thicknesses and the orientations of the orthodontic bite plate were acquired. CONCLUSION: An individualized 3D masticatory system model was constructed using advanced 3D data processing software that integrated 3D images from different sources. Individualized mandibular movement and masticatory muscle performance were simulated using this model. The analysis of the bite force generated on the lower incisors with the orthodontic bite plate suggested that a thickness of 3 mm may be appropriate for clinical use.

Classification and characteristics of pterygoid process fracture associated with maxillary transverse fracture.

OBJECTIVE: This study aimed to classify pterygoid process fractures associated with maxillary transverse fractures. STUDY DESIGN: Pterygoid process fractures in 100 patients with maxillary transverse fractures were observed 2- and 3-dimensionally using image processing software. Fracture line course and height and sphenoid sinus involvement were recorded. RESULTS: Pterygoid process fractures were classified as follows: class I, vertical (simple separation between medial and lateral plates); or class II, transverse (3 subcategories according to location of fracture line: II-1, within pterygoid fossa; II-2, above pterygoid fossa, not extending to sphenoid sinus floor; II-3, above pterygoid fossa, involving sphenoid sinus floor). Class I fracture was observed on 5 sides (2.7%); II-1, on 125 (66.5%); II-2, on 36 (19.1%); and II-3, on 22 (1.7%). CONCLUSIONS: Pterygoid process fractures were predominantly near the upper edge of the pterygoid fossa. Pneumatization of the pterygoid process is a risk in fractures involving the sphenoid sinus floor.