Helical distraction is superior to linear and circular distraction in mandibular distraction osteogenesis: an in silico study.

Helical mandibular distraction is theoretically better than linear or circular distraction. However, it is not known whether this more complex treatment will result in unquestionably better outcomes. Therefore, the best attainable outcomes of mandibular distraction osteogenesis were evaluated in silico, given the constraints of linear, circular, and helical motion. This cross-sectional kinematic study included 30 patients with mandibular hypoplasia who had been treated with distraction, or to whom this treatment had been recommended. Demographic information and the computed tomography (CT) scans showing the baseline deformity were collected. The CT scans of each patient were segmented and three-dimensional models of the face created. Then, the ideal distraction outcomes were simulated. Next, the most favorable helical, circular, and linear distraction movements were calculated. Finally, errors were measured: misalignment of key mandibular landmarks, misalignment of the occlusion, and changes in intercondylar distance. Helical distraction produced trivial errors. In contrast, circular and linear distractions resulted in errors that were statistically and clinically significant. Helical distraction also preserved the planned intercondylar distance, while circular and linear distractions led to unwanted changes in the intercondylar distance. It is now evident that helical distraction offers a new strategy to improve the outcomes of mandibular distraction osteogenesis.

Helical distraction is superior to linear distraction in maxillary distraction osteogenesis: an in silico study.

This in silico kinematic study was performed to evaluate the best attainable outcomes of maxillary distraction osteogenesis given the constraints of linear and helical motion. The study sample included the retrospective records of 30 patients with maxillary retrusion who had been treated with distraction or had been recommended this treatment. The primary outcomes were the errors of linear and helical distraction. The study measured two types of error: misalignment of key upper jaw landmarks and misalignment of the occlusion. Concerning the misalignment of key landmarks, the median misalignments resulting from helical distraction were minimal; the interquartile ranges were also minimal. The median misalignments and interquartile ranges that resulted from linear distraction were significantly larger. Regarding the occlusal misalignments, helical distraction produced minor occlusal misalignments, while linear distraction produced significantly larger errors. The results of this study confirmed that helical motion is the ideal motion for LeFort I distraction.

Clinical feasibility of deep learning-based automatic head CBCT image segmentation and landmark detection in computer-aided surgical simulation for orthognathic surgery.

The purpose of this ambispective study was to investigate whether deep learning-based automatic segmentation and landmark detection, the SkullEngine, could be used for orthognathic surgical planning. Sixty-one sets of cone beam computed tomography (CBCT) images were automatically inferred for midface, mandible, upper and lower teeth, and 68 landmarks. The experimental group included automatic segmentation and landmarks, while the control group included manual ones that were previously used to plan orthognathic surgery. The qualitative analysis of segmentation showed that all of the automatic results could be used for computer-aided surgical simulation. Among these, 98.4% of midface, 70.5% of mandible, 98.4% of upper teeth, and 93.4% of lower teeth could be directly used without manual revision. The Dice similarity coefficient was 96% and the average symmetric surface distance was 0.1 mm for all four structures. With SkullEngine, it took 4 minutes to complete the automatic segmentation and an additional 10 minutes for a manual touchup. The results also showed the overall mean difference between the two groups was 2.3 mm for the midface and 2.4 mm for the mandible. In summary, the authors believe that automatic segmentation using SkullEngine is ready for daily practice. However, the accuracy of automatic landmark digitization needs to be improved.

[Neurocognitive impairment and characteristics of neurocognitive performance among people with HIV on antiretroviral treatment].

Objective: Using two measuring tools to examine the prevalence and correlates of neurocognitive impairment (NCI) as well as characteristics of neurocognitive performance among people with HIV (PWH) on antiretroviral treatment (ART). Methods: A total of 2 250 treated PWH from the Comparative HIV and Aging Research in Taizhou (CHART) were recruited in Taizhou, Zhejiang province. The Chinese version of the Mini-mental State Examination (MMSE) and the International HIV Dementia Scale (IHDS) were used to evaluate their neurocognitive performance. Cluster analysis was conducted on the seven cognitive domains in the scale. Results: Among 2 250 treated PWH, 48.0% (1 080/2 250) were aged 45 to 89, 79.2% (1 782/2 250) were male, and 37.8% (852/2 250) had primary school education or below. The prevalence of neurocognitive impairment judged by MMSE and IHDS among HIV-infected people was 14.3% (321/2 250) and 31.8% (716/2 250), respectively. Aged 60 to 89 (aOR=2.63, 95%CI:1.52-4.56), depressive symptoms (aOR=5.58, 95%CI:4.20-7.40) and treatment with EFV (aOR=2.86, 95%CI:1.89-4.34) were main risk factors of NCI diagnosed by MMSE. Male (aOR=0.71, 95%CI:0.51-1.00), overweight (aOR=0.63, 95%CI:0.44-0.89), and high education level (aOR=0.11, 95%CI:0.05-0.25) were protective factors of NCI diagnosed by MMSE. Aged 60 to 89 (aOR=3.10, 95%CI:2.09-4.59), depressive symptoms (aOR=1.78, 95%CI:1.44-2.20) and treatment with EFV (aOR=1.79, 95%CI:1.41-2.29) were risk factors of NCI diagnosed by IHDS. Male (aOR=0.75, 95%CI:0.58-0.97), underweight (aOR=0.67, 95%CI:0.47-0.96), baseline CD4+ T lymphocyte (CD4) counts ≥350 cells/µl (aOR=0.69, 95%CI:0.53-0.91) and high education level (aOR=0.23, 95%CI:0.14-0.39) were protective factors of NCI diagnosed by IHDS. The neurocognitive performance of HIV-infected people can be divided into four main types. Among four types, age, gender, education level, alcohol drinking, depressive symptoms, waist-to-hip ratio, hypertension, diabetes, baseline CD4 counts and treatment with EFV were different statistically (all P<0.05). Conclusions: There are four main types of neurocognitive performance in treated PWH. The prevalence of NCI is high among this population, underscoring the need for tailored prevention and intervention.

Clinical feasibility evaluation of digital dental articulation for three-piece maxillary orthognathic surgery: a proof-of-concept study.

Digital dental articulation for three-piece maxillary orthognathic surgery is challenging. The purpose of this proof-of-concept study was to evaluate the clinical feasibility of a newly developed mathematical algorithm to digitally establish the final occlusion for three-piece maxillary surgery. Five patients with jaw deformities who had undergone a three-piece double-jaw surgery that was planned virtually were randomly selected for this study. The final occlusion had been hand-articulated using stone casts, scanned into the computer and used in the surgery. These hand-articulated occlusions served as the control group. To form the experimental group, the three-piece maxillary dental arch was articulated again automatically from the patient's original occlusion using the mathematical algorithm. The hand- and algorithm-articulated occlusions were then evaluated qualitatively by two experienced orthodontists. A quantitative evaluation was also performed. The results of the qualitative evaluation showed that all of the three-piece occlusions, hand- and algorithm-articulated, were clinically acceptable based on the American Board of Orthodontics grading system. When compared, two of the algorithm-articulated occlusions were clearly better (40%), one was the same (20%), and two were slightly worse (40%) than the hand-articulated occlusions. All of the quantitative measurements were comparable between the two articulation methods. In conclusion, the results of this study demonstrate that it is clinically feasible to digitally articulate the three-piece maxillary arch to the intact mandibular dental arch.

Fluctuating asymmetry of the normal facial skeleton.

The purpose of this study was to produce reliable estimations of fluctuating facial asymmetry in a normal population. Fifty-four computed tomography (CT) facial models of average-looking and symmetrical Chinese subjects with a class I occlusion were used in this study. Eleven midline landmarks and 12 pairs of bilateral landmarks were digitized. The repeatability of the landmark digitization was first evaluated. A Procrustes analysis was then used to measure the fluctuating asymmetry of each CT model, after all of the models had been scaled to the average face size of the study sample. A principal component analysis was finally used to establish the direction of the fluctuating asymmetries. The results showed that there was excellent absolute agreement among the three repeated measurements. The mean fluctuating asymmetry of the average-size face varied at each anthropometric landmark site, ranging from 1.0mm to 2.8mm. At the 95% upper limit, the asymmetries ranged from 2.2mm to 5.7mm. Most of the asymmetry of the midline structures was mediolateral, while the asymmetry of the bilateral landmarks was more equally distributed. These values are for the average face. People with larger faces will have higher values, while subjects with smaller faces will have lower values.

New approach to establish an object reference frame for dental arch in computer-aided surgical simulation.

The purpose of this study was to develop a principal component analysis-based adaptive minimum Euclidean distances (PAMED) approach to establish an optimal object reference frame for symmetrical alignment of the dental arch during computer-aided surgical simulation (CASS). It was compared with our triangular methods and the standard principal component analysis (PCA) method. Thirty sets of maxillary digital models were used. Midsagittal and occlusal planes were ranked by three experienced evaluators based on their clinical judgment. The results showed that for the midsagittal plane, all three evaluators ranked "ideal" for all 30 models with the PAMED method, 28 with the triangular method, and at least 11 with the PCA method. For the occlusal plane, one evaluator ranked all 30 models "ideal" with both the PAMED and the PCA methods while the other two evaluators ranked all 30 models "ideal" with the triangular method. However, the differences among the three methods were minimal. In conclusion, our PAMED method is the most reliable and consistent approach for establishing the object reference frame for the dental arch in orthognathic surgical planning. The triangular method should be used with caution because it can be affected by dental arch asymmetry. The standard PCA method is not recommended.

There is variability in our perception of the standard head orientation.

The purposes of this study were to determine: (1) whether an observer's perception of the correct anatomical alignment of the head changes with time, and (2) whether different observers agree on the correct anatomical alignment. To determine whether the perception of the correct anatomical alignment changes with time (intra-observer comparison), a group of 30 observers were asked to orient, into anatomical alignment, the three-dimensional (3D) head photograph of a normal man, on two separate occasions. To determine whether different observers agree on the correct anatomical alignment (inter-observer comparison), the observed orientations were compared. The results of intra-observer comparisons showed substantial variability between the first and second anatomical alignments. Bland-Altman coefficients of repeatability for pitch, yaw, and roll, were 6.9°, 4.4°, and 2.4°, respectively. The results of inter-observer comparisons showed that the agreement for roll was good (sample variance 0.4, standard deviation (SD) 0.7°), the agreement for yaw was moderate (sample variance 2.0, SD 1.4°), and the agreement for pitch was poor (sample variance 15.5, SD 3.9°). In conclusion, the perception of correct anatomical alignment changes considerably with time. Different observers disagree on the correct anatomical alignment. Agreement among multiple observers was bad for pitch, moderate for yaw, and good for roll.

A new approach of splint-less orthognathic surgery using a personalized orthognathic surgical guide system: A preliminary study.

The purpose of this study was to evaluate a personalized orthognathic surgical guide (POSG) system for bimaxillary surgery without the use of surgical splint. Ten patients with dentofacial deformities were enrolled. Surgeries were planned with the computer-aided surgical simulation method. The POSG system was designed for both maxillary and mandibular surgery. Each consisted of cutting guides and three-dimensionally (3D) printed custom titanium plates to guide the osteotomy and repositioning the bony segments without the use of the surgical splints. Finally, the outcome evaluation was completed by comparing planned outcomes with postoperative outcomes. All operations were successfully completed using the POSG system. The largest root-mean-square deviations were 0.74mm and 1.93° for the maxillary dental arch, 1.10mm and 2.82° for the mandibular arch, 0.83mm and 2.59° for the mandibular body, and 0.98mm and 2.45° for the proximal segments. The results of the study indicated that our POSG system is capable of accurately and effectively transferring the surgical plan without the use of surgical splint. A significant advantage is that the repositioning of the bony segments is independent to the mandibular autorotation, thus eliminates the potential problems associated with the surgical splint.

Real-time PCR assay with high resolution melting for EGFR and BIM mutation of lung cancer.

OBJECTIVE: To establish and develop a reliable and simple Real-time PCR assay with high resolution melting (Real-time PCR-HRM) method for detection epidermal growth factor (EGFR) and BIM mutation of lung cancer and looking for effective targeted drugs to control lung cancer. PATIENTS AND METHODS: A total of 6858 participants (2538 cases with lung cancer and 4275 healthy controls who took part in the study by doing the physical examination in Shanghai Xuhui community) were recruited in the study. Clinical characteristics and 5 ml peripheral blood were collected from each participant, and the DNA has been extracted, which were determined the EGFR and BIM mutation by Real-time PCR-HRM. Data were recorded and Statistical analyses. RESULTS: All samples completed the study. BIM deletion polymorphism was no related with age, sex, and smoking or EGFR mutation. CONCLUSIONS: There were no relations among BIM deletion polymorphism, EGFR mutation or lung cancer risk. HRM is a novel procedure and provides rapid, sensitive, specific and simultaneous detection for gene mutation of cancer patients for predicting the efficacy of targeted therapy.

A new design of CAD/CAM surgical template system for two-piece narrowing genioplasty.

The purpose of this study was to develop and validate a new chin template system for a two-piece narrowing genioplasty. Nine patients with wide chin deformities were enrolled. Surgeries were planned with the computer-aided surgical simulation (CASS) planning method. Surgical splints and chin templates were designed in a computer and fabricated using a three-dimensional printing technique. The chin template system included a cutting guide and a repositioning guide for a two-piece narrowing genioplasty. These guides were also designed to avoid the mental foramen area and inferior alveolar nerve loops during the osteotomy, for nerve protection. After surgery, the outcome evaluation was completed by first superimposing the postoperative computed tomography model onto the planned model, and then measuring the differences between the planned and actual outcomes. All surgeries were completed successfully using the chin template system. No inferior alveolar nerve damage was seen in this study. With the use of the chin templates, the largest linear root mean square deviation (RMSD) between the planned and the postoperative chin segments was 0.7mm and the largest angular RMSD was 4.5°. The results showed that the chin template system provides a reliable method of transfer for two-piece osseous narrowing genioplasty planning.

The primal sagittal plane of the head: a new concept.

To assess facial form, one has to determine the size, position, orientation, shape, and symmetry of the different facial units. Many of these assessments require a frame of reference. The customary coordinate system used for these assessments is the 'standard anatomical frame of reference', a three-dimensional Cartesian system made by three planes: the sagittal, the axial, and the coronal. Constructing the sagittal plane seems simple, but because of universal facial asymmetry, it is complicated. Depending on the method one selects, one can build hundreds of different planes, never knowing which one is correct. This conundrum can be solved by estimating the sagittal plane a patient would have had if his or her face had developed symmetrically. We call this the 'primal sagittal plane'. To estimate this plane we have developed a mathematical algorithm called LAGER (Landmark Geometric Routine). In this paper, we explain the concept of the primal sagittal plane and present the structure of the LAGER algorithm.

Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 1: planning sequence.

The success of craniomaxillofacial (CMF) surgery depends not only on the surgical techniques, but also on an accurate surgical plan. The adoption of computer-aided surgical simulation (CASS) has created a paradigm shift in surgical planning. However, planning an orthognathic operation using CASS differs fundamentally from planning using traditional methods. With this in mind, the Surgical Planning Laboratory of Houston Methodist Research Institute has developed a CASS protocol designed specifically for orthognathic surgery. The purpose of this article is to present an algorithm using virtual tools for planning a double-jaw orthognathic operation. This paper will serve as an operation manual for surgeons wanting to incorporate CASS into their clinical practice.

Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 2: three-dimensional cephalometry.

Three-dimensional (3D) cephalometry is not as simple as just adding a 'third' dimension to a traditional two-dimensional cephalometric analysis. There are more complex issues in 3D analysis. These include how reference frames are created, how size, position, orientation and shape are measured, and how symmetry is assessed. The main purpose of this article is to present the geometric principles of 3D cephalometry. In addition, the Gateno-Xia cephalometric analysis is presented; this is the first 3D cephalometric analysis to observe these principles.

Celecoxib inhibits ß-catenin-dependent survival of the human osteosarcoma MG-63 cell line.

Cyclo-oxygenase (COX)-2 inhibitors may exert antitumour effects through COX-2-independent mechanisms. This study investigated the effects of the COX-2 inhibitor celecoxib on the viability of the human osteosarcoma MG-63 cell line and its ß-catenin signalling pathway. Cell viability and apoptosis were examined in celecoxib-treated cells or after ß-catenin knockdown in vitro. Analyses were performed to detect glycogen synthase kinase (GSK)-3ß, phosphorylated GSK-3ß, ß-catenin, c-Myc and cyclin D1 proteins, and mRNA levels of ß-catenin, c-Myc and CCND1 (encoding cyclin D1). ß-Catenin was shown to be required for MG63 cell survival and celecoxib exerted an inhibitory effect on the viability of cultured MG-63 cells in a time- and dose-dependent manner. ß-Catenin protein decreased in the cytosol and nucleus following celecoxib treatment (from 6 h after initiation of treatment onwards; lowest protein levels were reached at > 72 h). Significant reductions in ß-catenin, c-Myc and CCND1 mRNA were observed. Celecoxib inhibited MG-63 cell viability, possibly by activating GSK-3ß and inhibiting ß-catenin-dependent gene transcription, suggesting a role for celecoxib in osteosarcoma treatment.