Soft Tissue Features Research Articles

IN-LINE METHOD OF X-RAY PHASE-CONTRAST MICRO-CT USING A WIDE-FOCUS LABORATORY SOURCE

An experimental implementation of the “in-line” method of X-ray phase contrast using a standard wide-focus X-ray tube as a polychromatic source is described. Using the proposed experimental scheme, in vitro tomographic measurements of a sample of human brain pineal gland are carried out, and the morphological structure of the soft tissues of this organ is visualized based on the results obtained. The advantage of phase-contrast tomography in comparison with traditional absorption tomography for studying the structural features of soft tissues is experimentally demonstrated. The “in-line” phase-contrast scheme, implemented on a laboratory setup, allows tomographic study of samples with linear dimensions of several millimeters and a resolution of ∼20 μm.

The effect of diabetes and tissue depth on adipose chamber size and plantar soft tissue features

BackgroundPlantar ulceration is a serious complication of diabetes. However, the mechanism of injury initiating ulceration remains unclear. The unique structure of the plantar soft tissue includes superficial and deep layers of adipocytes contained in septal chambers, however, the size of these chambers has not been quantified in diabetic or non-diabetic tissue. Computer-aided methods can be leveraged to guide microstructural measurements and differences with disease status. MethodsAdipose chambers in whole slide images of diabetic and non-diabetic plantar soft tissue were segmented with a pre-trained U-Net and area, perimeter, and minimum and maximum diameter of adipose chambers were measured. Whole slide images were classified as diabetic or non-diabetic using the Axial-DeepLab network, and the attention layer was overlaid on the input image for interpretation. ResultsNon-diabetic deep chambers were 90 %, 41 %, 34 %, and 39 % larger in area (26,954 ± 2428 µm2 vs 14,157 ± 1153 µm2), maximum (277 ± 13 µm vs 197 ± 8 µm) and minimum (140 ± 6 µm vs 104 ± 4 µm) diameter, and perimeter (405 ± 19 µm vs 291 ± 12 µm), respectively, than the superficial (p < 0.001). However, there was no significant difference in these parameters in diabetic specimens (area 18,695 ± 2576 µm2 vs 16627 ± 130 µm2, maximum diameter 221 ± 16 µm vs 210 ± 14 µm, minimum diameter 121 ± 8 µm vs 114 ± 7 µm, perimeter 341 ± 24 µm vs 320 ± 21 µm). Between diabetic and non-diabetic chambers, only the maximum diameter of the deep chambers differed (221 ± 16 µm vs 277 ± 13 µm). The attention network achieved 82 % accuracy on validation, but the attention resolution was too coarse to identify meaningful additional measurements. ConclusionsAdipose chamber size differences may provide a basis for plantar soft tissue mechanical changes with diabetes. Attention networks are promising tools for classification, but additional care is required when designing networks for identifying novel features. Data AvailabilityAll images, analysis code, data, and/or other resources required to replicate this work are available from the corresponding author upon reasonable request.

Initial results of covering soft tissue defects in the foot using the lateral supramalleolar flap nourishing by the dorsal vessels anastomosis with the peroneal artery.

Covering of skin defects in the foot region endures a significant challenge because of the anatomical characteristics of soft tissue. This research estimated the initial results of reconstruction of foot skin defects using lateral supramalleolar flap. This is a prospective observational study conducted from Dec 2017 to Dec 2021 at the Hospital for Traumatology and Orthopaedics, Ho Chi Minh City, Vietnam. Gathered information about demography, etiology, size of skin defect, size of flap, time of surgery, and post operation data. Using Stata 16.0 to analize data. Patients in this research included 21 males and 6 females. The mean age was 42 (ranging from 15 to 68) years. The range of size of skin defects was from 9 to 80 cm2. The success rate was 89%. Twenty-three cases had covered uneventful, and partial flap necrosis occurred in 4 cases (in which three patients were treated by skin graft later and one case got minor surgery suturing). Foot skin defects can be covered with good results by using the lateral supramalleolar flap nourishing by the dorsal vessels anastomosis with the peroneal artery.

Predicting mortality in acutely hospitalised older patients: the impact of model dimensionality

BackgroundThe prediction of long-term mortality following acute illness can be unreliable for older patients, inhibiting the delivery of targeted clinical interventions. The difficulty plausibly arises from the complex, multifactorial nature of the underlying biology in this population, which flexible, multimodal models based on machine learning may overcome. Here, we test this hypothesis by quantifying the comparative predictive fidelity of such models in a large consecutive sample of older patients acutely admitted to hospital and characterise their biological support.MethodsA set of 804 admission episodes involving 616 unique patients with a mean age of 84.5 years consecutively admitted to the Acute Geriatric service at University College Hospital were identified, in whom clinical diagnoses, blood tests, cognitive status, computed tomography of the head, and mortality within 600 days after admission were available. We trained and evaluated out-of-sample an array of extreme gradient boosted trees-based predictive models of incrementally greater numbers of investigational modalities and modelled features. Both linear and non-linear associations with investigational features were quantified.ResultsPredictive models of mortality showed progressively increasing fidelity with greater numbers of modelled modalities and dimensions. The area under the receiver operating characteristic curve rose from 0.67 (sd = 0.078) for age and sex to 0.874 (sd = 0.046) for the most comprehensive model. Extracranial bone and soft tissue features contributed more than intracranial features towards long-term mortality prediction. The anterior cingulate and angular gyri, and serum albumin, were the greatest intracranial and biochemical model contributors respectively.ConclusionsHigh-dimensional, multimodal predictive models of mortality based on routine clinical data offer higher predictive fidelity than simpler models, facilitating individual level prognostication and interventional targeting. The joint contributions of both extracranial and intracranial features highlight the potential importance of optimising somatic as well as neural functions in healthy ageing. Our findings suggest a promising path towards a high-fidelity, multimodal index of frailty.

Assessment of dental malocclusion and soft-tissue features among children with special needs in the Western UP region: A cross-sectional study.

Assessment of dental malocclusion and soft-tissue features among children with special needs and their correlation with normal children. A cross-sectional study was carried out among 128 children (63 special health-care needs children and 65 normal children), between 8 and 18 years of age. Two special schools (Vatsalya and Jeevandhara) were included in the study for case group and two local schools (one government and one private) were included in the study for control group. Index of Orthodontic Treatment Need was used to measure the malocclusion. To assess and compare various facial features, extra-oral photographs were taken from two different views (frontal and side). Data were analyzed using ANOVA and Chi-square test, with keeping level of significance at P < 0.05. The result of the present study demonstrated a significant difference between the study and control group with respect to overjet, caries, stains and calculus, soft-tissue facial profile, lip competency, and Korkhaus lip step. Soft-tissue comparison demonstrated facial asymmetry; lip incompetency was more prevalent in the study group compared to the control group. Overall, it was concluded that malocclusion was more prevalent in the study group compared to their counterparts. Malocclusion was more prevalent in children with disability compared to their counterparts. On clinical examination, a significant difference in relation to overjet, caries and stains, and calculus was observed, whereas a significant difference on soft-tissue examination was observed in facial profile, lip competency, and Korkhaus lip step in the study group compared to normal children.

Impact of peri-implant soft tissue characteristics on health and esthetics.

To review the impact of key peri-implant soft tissue characteristics on health and esthetics. The keratinized mucosa width (KMW), the mucosal thickness (MT), and the supracrestal tissue height (STH) are essential components of the peri-implant soft tissue phenotype. An inadequate KMW (<2 mm) has been associated with local discomfort upon oral hygiene performance and increased risk for the onset of peri-implant diseases. A minimum buccal MT (≥2 mm) is generally required to prevent esthetic issues related to the effect of transmucosal prosthetic elements on the color of the mucosa and can also contribute to long-term mucosal stability. STH is directly related to marginal bone remodeling patterns during the early healing process that follows the connection of transmucosal prosthetic components. Short STH, generally defined as <3 mm, has been consistently associated with marginal bone loss resulting from the physiologic establishment of the mucosal seal. Insufficient STH may also derive into the fabrication of unfavorable transmucosal prosthetic contours, which frequently results in unpleasing esthetic outcomes and predisposes to submarginal biofilm accumulation. Peri-implant soft tissue dehiscences (PISTDs) are a type of peri-implant deformity that are associated with esthetic issues and often occur in sites presenting KMW, MT, and/or STH deficiencies. PISTDs should be correctly diagnosed and treated accordingly, usually by means of multidisciplinary therapy. Understanding the impact of different dimensional and morphologic features of the peri-implant mucosa on health and esthetic outcomes is fundamental to make appropriate clinical decisions in the context of tooth replacement therapy with implant-supported prostheses.

Norms of soft tissue cephalometric in the 18-25 age demography in Vietnam.

The soft-tissue layer and facial skeleton influence the harmony and equilibrium of the face. The evaluation of the patient's structural and soft-tissue features is one of the most crucial steps in preparing for the diagnosis and treatment of oral-maxillofacial orthodontics. Clinicians can intervene with the proper treatment at the proper time to achieve the best results by being aware of the traits and variations of soft tissue at various developmental stages and in various races. To obtain a consistent treatment result in terms of function and aesthetically pleasing results, patients, and forecast, the growth that may take place after the orthopedic therapy has concluded. To examine the soft-tissue features of the oral-maxillofacial area in Vietnamese adults (aged 18-25 years) by evaluating cephalometric radiographs. In a cross-sectional descriptive study, 85 students from Can Tho University of Medicine and Pharmacy took part. Students' lateral cephalograms were taken in compliance with the sample requirements. Men's lip protrusion (4.30 ± 0.71) was higher than women's (3.88 ± 0.97) (P = 0.024 <.05) and men's (-4.88 ± 0.93) chin lip groove depth was higher than women's (-4.24 ± 0.93) (P = 0.002), both with a P value of. 05. The study identified a statistically significant difference in the protrusion of the top lip and the depth of the cleft lip between the male and female, demonstrating that the soft-tissue features of Vietnamese students were distinct from those of other races.

Ultrassonografia como instrumento de avaliação do linfedema secundário ao câncer de mama: revisão sistemática

Abstract Lymphedema is a chronic and progressive disease characterized by fluid accumulation, causing tissue edema as a result of a compromised lymphatic system. Diagnostic ultrasound (DUS) is a method capable of assessing soft tissue characteristics that can be used reliably to diagnose lymphedema as well as for measuring tissue compliance in a clinical setting. This is a systematic review, aiming to evaluate articles that made use of DUS in management of lymphedema secondary to breast cancer. A total of 570 articles were selected, exported to the Rayyan QCRI review program, and then screened by two researchers. From this search, 25 articles were selected after the authors reached consensus and were catalogued as to their main results. Diagnostic ultrasound was identified as an advantageous method that is safe, minimally invasive, low cost, and radiation free and is useful for evaluating the efficacy of therapies used in lymphedema treatment.

Ultrasonography as an instrument to evaluate lymphedema secondary to breast cancer: systematic review.

Lymphedema is a chronic and progressive disease characterized by fluid accumulation, causing tissue edema as a result of a compromised lymphatic system. Diagnostic ultrasound (DUS) is a method capable of assessing soft tissue characteristics that can be used reliably to diagnose lymphedema as well as for measuring tissue compliance in a clinical setting. This is a systematic review, aiming to evaluate articles that made use of DUS in management of lymphedema secondary to breast cancer. A total of 570 articles were selected, exported to the Rayyan QCRI review program, and then screened by two researchers. From this search, 25 articles were selected after the authors reached consensus and were catalogued as to their main results. Diagnostic ultrasound was identified as an advantageous method that is safe, minimally invasive, low cost, and radiation free and is useful for evaluating the efficacy of therapies used in lymphedema treatment.

Indication and Success Rates of Skeletal Anchorage System in Orthodontics

Skeletal anchorage systems, a pivotal innovation in orthodontics, involve the use of Temporary Anchorage Devices (TADs) or mini-implants, providing stable anchor points in the bone to facilitate precise tooth movements. This comprehensive review article aims to investigate the indications and success rates of skeletal anchorage systems in orthodontics. The research, initiated on November 2nd, 2023, involved an extensive examination of existing literature, utilizing databases like PubMed, Web of Science, and Cochrane. Various components, including mini-screws, mini plates, palatal, buccal shelf implants, and infrazygomatic implants, have enriched orthodontic diversity. Mini screws have displayed remarkable success rates, with most complications related to manageable soft tissue inflammation. Gingival health and smoking habits have been identified as influential factors in mini screw implant success. Mini plates offer sturdy anchorage with resistance to root damage and fracture, surpassing mini screws in overall success rate. Age, implantation site viability, and soft tissue characteristics influence their success. Palatal and buccal shelf implants provide exceptional stability, enhancing the results of fixed bracket appliances. The anterior palatal region is a preferred site for implantation. Infrazygomatic implants, while offering commendable stability, display failure rates within the range of 21-28%, with compromised oral hygiene, immediate loading, inflammation, tooth mobility, and a high mandibular plane angle as potential failure factor. These anchorage methods have expanded treatment possibilities, offering effective solutions for challenging orthodontic cases and ultimately improving patient outcomes.

Impact of local predisposing/precipitating factors and systemic drivers on peri-implant diseases.

Strong evidence suggests the infectious nature of peri-implant diseases occurring in susceptible hosts. Epidemiological reports, though, indicate that peri-implantitis is a site-specific entity. Hence, the significance of local factors that may predispose/precipitate plaque accumulation and the impact of systemic drivers that alter the immune response are relevant in the prevention and management of peri-implant disorders. The purpose of the present review is to shed light on the significance of local and systemic factors on peri-implant diseases, making special emphasis on the associations with peri-implantitis. The biologic plausibility and supporting evidence aiming at providing a concluding remark were explored in the recent scientific literature for local predisposing/precipitating factors and systemic drivers related to peri-implant diseases. Local predisposing factors such as soft tissue characteristics, implant position and prosthetic design proved being strongly associated with the occurrence of peri-implant diseases. Hard tissue characteristics, however, failed to demonstrate having a direct association with peri-implant diseases. Robust data points toward the strong link between residual sub-mucosal cement and peri-implant diseases, while limited data suggests the impact of residual sub-mucosal floss and peri-implantitis. Systemic drivers/habits such as hyperglycemia and smoking showed a strong negative impact on peri-implantitis. However, there is insufficient evidence to claim for any link between metabolic syndrome, atherosclerotic cardiovascular disease, and obesity and peri-implant diseases. Local predisposing/precipitating factors and systemic drivers may increase the risk of peri-implant diseases. Therefore, comprehensive anamnesis of the patients, educational/motivational programs and exhaustive prosthetically-driven treatment planning must be fostered aiming at reducing the rate of biological complications in implant dentistry.

Effects of Two-Phase Treatment with Functional Appliances Followed by Extraction versus One-Phase Treatment with Extraction in Class II Growing Patients: A Case-Control Study.

Objectives: Fixed appliance treatment with premolar extraction is often required after functional appliance treatment to relieve crowding and improve facial aesthetics in the Asian population. This study compared the treatment efficacy of two approaches for treating Class II division 1 malocclusion: functional appliance followed by fixed appliance treatment with extraction (two-phase) and fixed appliance treatment with extraction (one-phase). Methods: Growing skeletal Class II patients with an overjet of ≥6 mm treated with two- or one-phase orthodontics were included. The two groups consisted of 29 patients (mean age = 12.55) and 30 patients (mean age = 12.72), respectively. Pre- and post-treatment cephalograms were analysed and skeletal, dental, and soft tissue characteristics were compared using independent t-tests. Treatment changes were compared within and between groups using paired and independent t-tests, respectively. Stepwise discriminant analysis was performed to identify the variables that best predicted pre-treatment group allocations. Results: At baseline, there were no significant between-group differences in age, gender, cervical vertebral maturation, or overjet. The two-phase group had greater Class II skeletal discrepancies (ANB angle and Wits appraisal). During treatment, the two-phase group showed greater improvements in intermaxillary relationship and facial convexity compared with the one-phase group (p < 0.01). Following treatment, the two-phase group had a greater L1/APog distance (p < 0.05). Facial convexity and Wits appraisal were identified as parameters significantly influencing the clinicians’ decision to use a one- or two-phase approach. Conclusions: In patients requiring premolar extraction, two-phase (vs. one-phase) treatment produced greater improvements in the intermaxillary relationship and facial convexity.

Soft tissue features of peri-implant diseases and related treatment.

The need for soft tissue grafting at implant sites for preventing and treating peri-implant diseases is a currently investigated and debated topic. The aim of this manuscript is to explore the inflammatory mechanisms at the peri-implant soft tissue compartment, to distinguish the structural components of the peri-implant soft tissue phenotype and their role on peri-implant health, and to appraise the clinical indications and expected outcomes of soft tissue augmentation procedures at peri-implant diseased sites. This narrative review depicts the inflammatory biomarkers and mediators in the peri-implant crevicular fluid utilized to diagnose peri-implant disease and that have been shown to be associated with peri-implant soft tissue phenotype modification and disease resolution. The impact of the peri-implant soft tissue phenotype, involving keratinized mucosa (KM) width, attached mucosa (AM), mucosal thickness (MT), and supracrestal tissue height (STH), on peri-implant health, esthetic, patient's comfort and disease prevention are discussed. The manuscript also illustrates the use of ultrasonography for the detection of peri-implant health/disease and the evaluation of the treatment outcomes following surgical therapies. Current evidence indicates that soft tissue phenotype modification at implant sites with inadequate KM width, AM and MT can be beneficial for promoting peri-implant health and improving patient's comfort and hygiene procedures. Treatment approaches and outcomes from the available literature on soft tissue phenotype modification in combination with conventional techniques at sites with peri-implant mucositis or peri-implantitis are presented and discussed in detail. Soft tissue grafting can be beneficial in preventing and treating peri-implant diseases. Clinical recommendations based on the disease, soft tissue phenotype characteristics and bone defect morphology are provided for a comprehensive hard- and soft-tissue-oriented treatment of peri-implant disease.

Explainability and controllability of patient-specific deep learning with attention-based augmentation for markerless image-guided radiotherapy.

We reported the concept of patient-specific deep learning (DL) for real-time markerless tumor segmentation in image-guided radiotherapy (IGRT). The method was aimed to control the attention of convolutional neural networks (CNNs) by artificial differences in co-occurrence probability (CoOCP) in training datasets, that is, focusing CNN attention on soft tissues while ignoring bones. However, the effectiveness of this attention-based data augmentation has not been confirmed by explainable techniques. Furthermore, compared to reasonable ground truths, the feasibility of tumor segmentation in clinical kilovolt (kV) X-ray fluoroscopic (XF) images has not been confirmed. The first aim of this paper was to present evidence that the proposed method provides an explanation and control of DL behavior. The second purpose was to validate the real-time lung tumor segmentation in clinical kV XF images for IGRT. This retrospective study included 10 patients with lung cancer. Patient-specific and XF angle-specific image pairs comprising digitally reconstructed radiographs (DRRs) and projected-clinical-target-volume (pCTV) images were calculated from four-dimensional computer tomographic data and treatment planning information. The training datasets were primarily augmented by random overlay (RO) and noise injection (NI): RO aims to differentiate positional CoOCP in soft tissues and bones, and NI aims to make a difference in the frequency of occurrence of local and global image features. The CNNs for each patient-and-angle were automatically optimized in the DL training stage to transform the training DRRs into pCTV images. In the inference stage, the trained CNNs transformed the test XF images into pCTV images, thus identifying target positions and shapes. The visual analysis of DL attention heatmaps for a test image demonstrated that our method focused CNN attention on soft tissue and global image features rather than bones and local features. The processing time for each patient-and-angle-specific dataset in the training stage was ∼30min, whereas that in the inference stage was 8ms/frame. The estimated three-dimensional 95 percentile tracking error, Jaccard index, and Hausdorff distance for 10 patients were 1.3-3.9mm, 0.85-0.94, and 0.6-4.9mm, respectively. The proposed attention-based data augmentation with both RO and NI made the CNN behavior more explainable and more controllable. The results obtained demonstrated the feasibility of real-time markerless lung tumor segmentation in kV XF images for IGRT.

Assessment of soft and hard tissue characteristics of ridge preservation at molar extraction sites with severe periodontitis: a randomized controlled trial

BackgroundChanges in alveolar bone dimension after tooth extraction may affect placement of the subsequent implant, resulting in ridge deficiency that can adversely impact long-term implant stability or aesthetics. Alveolar ridge preservation (ARP) was effective in reducing the amount of ridge resorption following tooth extraction. There is sparse evidence regarding the benefit of ARP at periodontally compromised molar extraction sockets. This study will be a randomized trial to assess the soft tissue contour, radiographical, and histological changes of ARP at molar extraction sites in order to compare severe periodontitis cases with natural healing results and determine the most beneficial and least traumatic clinical treatment for such patients.MethodsThis research is designed as a two-group parallel randomized controlled trial. The total number of tooth extraction sites will be 70 after calculation with power analysis. Teeth will be randomly assigned to two groups with the test group conducting ridge preservation and the control group healing naturally. Periodontal examination, cone beam-computed tomography (CBCT) data, and stereolithographic (STL) files obtained by intraoral scanning will be collected through the follow-up period, and bone biopsy samples would be obtained during implant surgery. The primary outcomes are the vertical and horizontal change of alveolar ridge measured on CBCT images, soft tissue contour changes evaluated by superimposing the digital impressions, alterations of mucosa thickness (as measured by superimposing the CBCT data and STL files), histological features of implant sites and periodontal parameter changes. The secondary outcomes are patient-reported post-operative reaction and conditions of simultaneous bone graft or sinus lifting procedures during implantation.DiscussionThis study will provide information about hard and soft tissue dimension changes and histomorphology evaluation following ARP and natural healing in periodontally compromised molar sites, which may contribute to complement the missing information of ARP at periodontally compromised molar extraction sockets.Trial registrationChinese Clinical Trial Register (ChiCTR) ChiCTR2200056335. Registered on February 4, 2022, Version 1.0.

Morphological and radiological study of the shoulder and elbow joints of the giant anteater (Myrmecophaga tridactyla).

The giant anteater (Myrmecophaga tridactyla) has specialized thoracic limbs to forage by breaking the walls of anthills and termite mounds. They also play critical roles in defense posture and locomotion. This study aimed to provide a morphological and radiographic description of the shoulder joint and elbow joint of the giant anteater. Both joints of 13 tamanduas were assessed by morphological dissections and histological evaluation and radiographies without and with positive contrast. The radiographic projections selected to this study were the mediolateral and craniocaudal projections. The radiographic and anatomical findings were compared with the following results: the shoulder joint had a continuous joint capsule with the tendon sheaths of the short head and long head of the biceps brachii muscle, which could be visualized with an injection of 3 ml of intra-articular contrast. The shoulder joint arthrography was performed with the needle positioned cranially to the joint for contrast injection. The elbow joint presented three articular compartments, and the insertion of the joint capsule was proximal to the radial fossa and distal to the radial tuberosity in the radial notch of the ulna, which were possible to identify with 2 ml of intra-articular contrast. The elbow joint arthrography was performed with the needle positioned laterally to the joint for contrast injection. Moreover, the joint capsule presented a caudomedial distention and fat pads. The powerful muscles of the forelimb play a fundamental role in maintaining the shoulder joint and elbow joint stability due to bony adaptations and the absence of usual ligaments. The morphological and radiological study provided relevant information on the soft-tissue characteristics of shoulder and elbow joints, which may aid clinical-surgical and diagnostic imaging procedures.

Force-Sensorless Identification and Classification of Tissue Biomechanical Parameters for Robot-Assisted Palpation.

The implementation of robotic systems for minimally invasive surgery and medical procedures is an active topic of research in recent years. One of the most common procedures is the palpation of soft tissues to identify their mechanical characteristics. In particular, it is very useful to identify the tissue's stiffness or equivalently its elasticity coefficient. However, this identification relies on the existence of a force sensor or a tactile sensor mounted at the tip of the robot, as well as on measuring the robot velocity. For some applications it would be desirable to identify the biomechanical characteristics of soft tissues without the need for a force/tactile nor velocity sensors. An estimation of such quantities can be obtained by a model-based state observer for which the inputs are only the robot joint positions and its commanded joint torques. The estimated velocities and forces can then be employed for closed-loop force control, force reflection, and mechanical parameters estimation. In this work, a closed-loop force control is proposed based on the estimated contact forces to avoid any tissue damage. Then, the information from the estimated forces and velocities is used in a least squares estimator of the mechanical parameters. Moreover, the estimated biomechanical parameters are employed in a Bayesian classifier to provide further help for the physician to make a diagnosis. We have found that a combination of the parameters of both linear and nonlinear viscoelastic models provide better classification results: 0% misclassifications against 50% when using a linear model, and 3.12% when using only a nonlinear model, for the case in which the samples have very similar mechanical properties.

Hispanic adolescent lip response to extraction and nonextraction orthodontic treatment

In orthodontics, treatment aims to improve the patient's occlusion and overall facial appearance. Extraction of 4 first premolars may improve the occlusion, but it may negatively impact a patient's facial harmony and create a "dished-in" appearance. Although many studies in orthodontic literature reviewed Caucasian patient soft-tissue change throughout extraction treatment, there is a void in the literature regarding Hispanic patients, who have different soft-tissue characteristics and may respond differently to extraction therapy. This study aimed to determine the influence of first premolar extractions on soft-tissue profile in Hispanic adolescents and whether there is a correlation between pretreatment lip strain and lip movement throughout treatment. Lateral cephalograms and study models of 60 Hispanic patients were evaluated at pretreatment and posttreatment stages. Patients were divided into nonextraction and extraction groups and further subdivided on the basis of pretreatment lip strain. Cephalometric analyses were compared between the groups and subgroups, and a correlation analysis was conducted. There was a significant difference in lip position change between nonextraction and extraction groups. There was a significant increase in upper vermillion lip thickness in the extraction group. There was no significant difference in lip position change between the minimal and moderate-severe lip strain extraction groups. There was no significant correlation between pretreatment crowding or lip strain and lip position change. Hispanic patients' lips may retract less than Caucasian patients' lips in response to extraction treatment. Pretreatment lip strain and crowding may have less effect on retrusive lip movement than in Caucasian patients.

A Constitutive Model to Characterize In Vivo Human Palmar Tissue.

In vivo characteristics of palmar soft tissue can be used to improve the accuracy of human models to explore and simulate a range of contact scenarios. Tissue characteristics can help to assess injury prevention strategies and designing technologies that depend on quantified physical contacts such as prosthetics, wearables, and assistive devices. In this study, a simplified quasi-linear viscoelastic (QLV) model was developed to quantify large deformation, in vivo soft tissue relaxation characteristics of the palm. We conducted relaxation tests on 11 young adults (6 males, 5 females, 18 < age < 30, mean age: 25 ± 4 yr) and 9 older adults (6 males, 3 females, age > 50, mean age: 61.5 ± 11.5 yr) using a 3 mm indenter to a depth of 50% of each participant's soft tissue thickness. The relaxation parameters of the QLV model were found to differ with age and sex, emphasizing the importance of using targeted material models to represent palmar soft tissue mechanics. Older adults showed on average 2.3-fold longer relaxation time constant compared to younger adults. It took 1.2-fold longer for young males to reach equilibrium than for young females; however, young females had a higher level of relaxation (36%) than young males (33%). Differences in specific QLV model parameters, P1, P2, and α were also found between age and sex groups. QLV characteristics differentiated by age and sex, add biofidelity to computational models which can provide a better representation of the diversity of tissue properties in the population.

Efficacy of platelet-rich fibrin in maxillary sinus augmentation and simultaneous implant placement in deficient maxillary ridges: A pilot comparative study

BackgroundRehabilitation with dental implants has become the most widely accepted treatment protocol for rehabilitation of lost natural teeth. Direct sinus lift is one of the most predictable procedures for augmenting the deficient posterior maxillary ridges. MethodsThe study was designed in patients with insufficient bone for implants in the maxillary posterior ridges. The test group received platelet-rich fibrin alone as filler, and the control group received a bone allograft. The residual bone height (RBH), implant mobility, and soft tissue characteristics between and within the groups were compared and analyzed. ResultsBoth the groups had considerable gain in RBH, and the intragroup analysis revealed clinical gain in bone height in both the groups, with the test group exhibiting statistically significant gain which kept on improving from 6 months with z= -3.477 and a p value of 0.001 to 9 months with z=-3.531 and a p value of 0.027. ConclusionThe results suggest that the use of platelet-rich fibrin alone improves the bone regeneration, thereby achieving predictable and stable augmentation of the sinus floor required for the success of implant therapy.