Tissue Dimensions Research Articles

Chemical Items Used for Preparing Tissue-Mimicking Material of Wall-Less Flow Phantom for Doppler Ultrasound Imaging.

The wall-less flow phantoms with recognized acoustic features (attenuation and speed of sound), interior properties, and dimensions of tissue were prepared, calibrated, and characterized of Doppler ultrasound scanning demands tissue-mimicking materials (TMMs). TMM phantoms are commercially available and ready-made for medical ultrasound applications. Furthermore, the commercial TMM phantoms are proper for ultrasound purpose or estimation of diagnostic imaging techniques according to the chemical materials used for its preparation. However, preparing a desirable TMM for wall-less flow phantom using a specific chemical material according to the specific applications is required for different flow. In this review, TMM and wall-less flow phantoms prepared using different chemical materials and methods were described. The chemical materials used in Doppler ultrasound TMM and wall-less flow phantoms fabricated over the previous decades were of high interest in this review.

Tissue integration of zirconia and titanium implants with and without buccal dehiscence defects.

PurposeThe purpose of the present study was to validate an experimental model for assessing tissue integration of titanium and zirconia implants with and without buccal dehiscence defects.MethodsIn 3 dogs, 5 implants were randomly placed on both sides of the mandibles: 1) Z1: a zirconia implant (modified surface) within the bony housing, 2) Z2: a zirconia implant (standard surface) within the bony housing, 3) T: a titanium implant within the bony housing, 4) Z1_D: a Z1 implant placed with a buccal bone dehiscence defect (3 mm), and 5) T_D: a titanium implant placed with a buccal bone dehiscence defect (3 mm). The healing times were 2 weeks (one side of the mandible) and 6 weeks (the opposite side).ResultsThe dimensions of the peri-implant soft tissue varied depending on the implant and the healing time. The level of the mucosal margin was located more apically at 6 weeks than at 2 weeks in all groups, except group T. The presence of a buccal dehiscence defect did not result in a decrease in the overall soft tissue dimensions between 2 and 6 weeks (4.80±1.31 and 4.3 mm in group Z1_D, and 4.47±1.06 and 4.5±1.37 mm in group T_D, respectively). The bone-to-implant contact (BIC) values were highest in group Z1 at both time points (34.15%±21.23% at 2 weeks, 84.08%±1.33% at 6 weeks). The buccal dehiscence defects in groups Z1_D and T_D showed no further bone loss at 6 weeks compared to 2 weeks.ConclusionsThe modified surface of Z1 demonstrated higher BIC values than the surface of Z2. There were minimal differences in the mucosal margin between 2 and 6 weeks in the presence of a dehiscence defect. The present model can serve as a useful tool for studying peri-implant dehiscence defects at the hard and soft tissue levels.

Tissue Processing for Stereological Analyses of Lung Structure in Chronic Obstructive Pulmonary Disease.

Quantitative data on lung structure, such as volume, surface area and length, are used for assessment of the functional performance of the lung during normal development and inflammatory-related diseases such as chronic obstructive pulmonary disorder (COPD), and carcinogenesis, in animal models. Stereology is considered as the gold standard to obtain quantitative data on lung structure, with a key advantage being to quantify irregular three-dimensional structures on the basis of measurement made on two-dimensional sections. Therefore, preservation of original tissue dimensions without shrinkage is vital for stereology.Three steps, fixation, sampling and embedding, are essential requirements to minimise tissue shrinkage to obtain theoretically unbiased estimates of stereological parameters of lung structures. Perfusion fixation by intratracheal instillation with 1.5% glutaraldehyde/1.5% formaldehyde at a pressure of 25cm fluid column is considered as one of the best methods. A systematic uniform random sampling scheme is then applied to the fixed lung to ensure each and every part of the lung is analysed, irrespective of homogeneity or heterogeneity of the structural distribution. The sampled tissue sections are then embedded in glycol methacrylate to minimise further tissue shrinkage. Here we describe the accurate fixation, sampling and embedding for stereological methods to quantify lung structures in mice.

An unusual cause of hypercalcemic crisis: Water-clear cell double parathyroid adenoma.

To evaluate the clinical characteristics of a patient operated for water-clear cell adenoma and to discuss these in the light of relevant literature. PubMed and Google Scholar were searched to identify articles related to water-clear cell adenoma using the following keywords: parathyroid tissue, parathyroid gland, parathyroid cells, parathyroid adenoma, parathyroid hyperplasia, water-clear-cell, and water clear cell. The search included case reports, review articles, and original articles that had been published between January 1990 and November 2014 without any restrictions on language. All articles that contained information on the study population and treatment related data were identified and retrieved. In addition, an evaluation was of a case of a 47-year-old male patient with PHC who was treated at our clinic was conducted. A total of 19 patients, including our new case, (age range: 18 to 81 years, mean±SD: 57.47±16.31 years) were included in the analysis. Eleven patients were female. Information about adenoma location was available from studies involving 17 patients and they indicated the following distribution of locations: left inferior (n=10), right superior (n=4). When preoperative imaging methods were examined, a false negative result was given by ultrasonography in 28.5% of patients and only 57.1% were positive on scintigraphy. Concomitant thyroid papillary carcinoma was determined in 1 patient. The mean tissue dimensions were 3.47±1.73 cm (range, 0.8-6.8 cm). Water-clear cell adenoma, which shows similar clinical characteristics to other parathyroid adenomas, is an uncommon cause of hyperparathyroidism.

Airway and hard tissue dimensions in children treated with early and later timed cervical headgear-a randomized controlled trial.

A Kloehn-type cervical headgear (CH) aims to correct skeletal jaw discrepancy in Class II children. A few studies have reported CH treatment effects on airway dimensions, but none of them have been randomized according to timing. To evaluate related craniofacial structures and pharyngeal airway dimensions in children with a Class II occlusion treated with CH and randomized into early and late treatment groups. Randomized, parallel-group, prospective controlled trial. The material comprised 67 seven-year-old children with a Class II occlusion. Sealed-envelope randomization in 1:1 ratio was used to divide the children into two equal groups. In the early group (EG, n = 33), CH treatment was started immediately or after eruption of the first maxillary molars. In the second, late group (LG, n = 34), the active CH treatment was started about one and half year later. The active CH treatment was continued in both groups until normal Class I occlusion on first molars was achieved. Cephalometric radiographs were taken from both groups at the beginning of follow-up (T0), at the beginning of CH treatment of the second group (T1), and at the end of CH treatment of the second group (T2). Changes in cephalometric measurements were used as primary outcomes. Blinding was applicable for outcome assessment. Fifty-six children completed the study. The posterior change in the position of the maxilla was significant for early treatment males at T0-T1 (SNA; P < 0.001, ANB; P = 0.009) and T0-T2 (SNA; P = 0.012). The palato-mandibular angle (PL-ML) decreased during T0-T1 in early treatment females (P = 0.018) and early treatment males (P = 0.037). The retroglossal airway increased (P = 0.010) in early treatment males at T0-T1. Highly significant positive correlations (P < 0.001) between skeletal and upper airway dimensions during early CH treatment were found in males. No harms were encountered. Despite the effective CH treatment, no harmful upper airway changes were found. NCT02010346.

Articular Cartilage Repair with Mesenchymal Stem Cells After Chondrogenic Priming: A Pilot Study.

Bone marrow-derived mesenchymal stromal stem cells (BMSCs) are a promising cell source for treating articular cartilage defects. The objective of this study was to assess a protocol that involved autologous transplantation of BMSCs into full-thickness cartilage defects in sheep following isolation, expansion, and a short period (4 days) of chondrogenic priming. The impact of oxygen tension during preimplantation culture was investigated. It was hypothesized that chondrogenically primed BMSCs would produce superior cartilaginous repair tissue relative to control defects, and that culture under hypoxia would yield improved repair tissue in comparison to normoxia. Ovine BMSCs were isolated, expanded to passage 2, seeded within a hyaluronic acid (HYAFF) scaffold, and primed ex vivo in chondrogenic medium for 4 days under normoxia (21% oxygen) or hypoxia (3% oxygen). Full-thickness, 7-mm-diameter articular cartilage defects were created in the femoral condyles of five sheep. Twenty defects were treated with normoxia-cultured, autologous BMSC-seeded scaffolds (eight); hypoxia-cultured, autologous BMSC-seeded scaffolds (eight); cell-free scaffolds (two); or no implants (two). Preimplantation priming was evaluated through gene expression analysis using reverse transcription quantitative polymerase chain reaction. After 6 months, histological assessment was performed on repair tissues with a modified O'Driscoll scoring system and tissue dimension analysis. Priming of preimplantation BMSC-seeded scaffolds in chondrogenic medium for 4 days resulted in significantly increased gene expression of hyaline cartilage-related collagen II and aggrecan relative to unprimed BMSCs (p < 0.05). Defects implanted with chondrogenically primed BMSC-seeded scaffolds developed cartilaginous repair tissues that contained safranin O-positive proteoglycans, and had significantly larger repair tissue areas, higher percentages of defect fill, and improved histological scores than cell-free controls (p < 0.05). Although hypoxic culture improved the preimplantation gene expression profile, a consistent difference in histological scores was not found between normoxia- and hypoxia-seeded BMSC-seeded scaffolds after 6 months (p = 0.90). This study demonstrates in a sheep model that (1) chondrogenic priming ex vivo improves the gene expression profile of BMSCs; (2) chondrogenically primed BMSCs are associated with the development of superior cartilaginous tissue to cell-free controls within cartilage defects; and (3) oxygen tension during preimplantation ex vivo culture does not consistently modulate cartilaginous repair tissue formation following BMSC transplantation into cartilage defects.

Dimensions of hard and soft tissue around adjacent, compared with single-tooth, zirconia implants

Preservation or regeneration of the papilla has always been a challenge around consecutive implants or with implants next to teeth, and many studies have evaluated the papilla’s behaviour and patterns based on surgical technique and prosthetic design, though evidence about its behaviour around zirconia implants is scarce. The aim of this study was to evaluate papilla behaviour between implants and teeth (tooth-implant group) and between consecutive implants (implant–implant group). Ninety patients with 122 zirconia implants (Straumann® PURE Ceramic Implant) were examined at the one-year follow up. We measured the effect of the distance: first from the base of the contact point of the crowns to the contact with bone at the implant site (D1); secondly, to the contact with the bone at the neighbouring tooth or implant site (D2); and thirdly on the papillary deficit (D3). In both the tooth-implant group and the implant–implant group, D1 and D2 correlated significantly with the papillary deficit (D3), whereas D2 was the major determinant factor (Spearman’s rho=0.60). In both groups, when D1 and D2 were <6mm, the papilla was present every time. The papillary deficit was significantly greater in the tooth-implant group than in the implant–implant group (p=0.048). We conclude that the ideal distance from the base of the contact point to the bone contact at the implant and to the bone contact at the adjacent tooth in both groups is <6mm. The height of the bone on the teeth adjacent to implants has a significant impact on that of the papilla.

Evaluation of peri-implant bone levels and soft tissue dimensions around zirconia implants—a three-year follow-up study

The aim of this study was to measure bone levels around zirconia implants during follow-up of up to 3 years. Additionally, the effect of clinical contact point positions on the papilla deficit was evaluated. Eighty-one patients with 105 zirconia implants were examined at the 3-year follow-up. Bone levels were measured on the date of implant placement and at 3 months, 1year, and 3 years thereafter. Distances between the first bone–implant contact and the contact point of the crowns and between the bone level at the adjacent tooth and the contact point of the crowns were assessed. The effect of the clinical contact point position on the papilla deficit was also assessed. Significant reductions in the distances between the bone–implant contact and the implant shoulder, as well as the contact point of the crowns, and between the bone level at the adjacent tooth and the contact point of the crowns, were found. A significant association was found between the papilla deficit and the height of the contact point. Implant survival was 100% and implant success was 95.4%. While zirconia implants presented little bone loss up to 1year, significant bone apposition was observed up to 3years. Low contact points correlated with full papillae, whereas high contact points were associated with a papilla deficit.

Effectiveness of Contour Augmentation with Guided Bone Regeneration: 10-Year Results

In aesthetic sites, the integrity of the facial bone wall dimension in the anterior maxilla is jeopardized by physiologic and structural changes postextraction. An effective regenerative protocol is key to reestablish and maintain the hard and soft tissue dimensions over time. The present prospective case series study examined the effectiveness of early implant placement with simultaneous contour augmentation through guided bone regeneration with a 2-layer composite graft in postextraction single-tooth sites over an observation period of 10 y among 20 patients. The median peri-implant bone loss was 0.35 mm between the 1- and 10-y examination. A success rate of 95% was obtained, with pleasing aesthetic outcomes and a high median Pink Esthetic Score (8). Implant crowns (ICs) revealed significant median facial recession between IC10y and IC1y (0.17 mm). The facial bone wall dimensions were assessed by preoperative cone beam computed tomography and 2 subsequent scans taken at 6 and 10 y. The median facial bone wall thickness increased significantly from 0 mm at surgery to 1.67 mm at the 10-y examination. The facial vertical bone wall peak (DIC) was located at a median distance of 0.16 mm coronal to the implant shoulder. The facial vertical bone loss of DIC amounted to 0.02 mm between 6 and 10 y. Equivalence testing was performed for the null hypothesis of a difference of >0.2 mm per year between 2 respective time points, showing stable bone conditions. Modulating factors influencing the regenerative outcomes at 10 y were the preoperative proximal crest width and soft tissue thickness. In conclusion, the present study confirmed the long-term effectiveness of early implant placement with simultaneous contour augmentation through guided bone regeneration with a 2-layer composite graft in postextraction single-tooth sites offering stable bone conditions with low risks of mucosal recessions over an observation period of 10 y (ClinicalTrials.gov NCT03252106).

The Functional Anatomy of Nerves Innervating the Ventral Grooved Blubber of Fin Whales (Balaenoptera Physalus).

Nerves that supply the floor of the oral cavity in rorqual whales are extensible to accommodate the dramatic changes in tissue dimensions that occur during "lunge feeding" in this group. We report here that the large nerves innervating the muscle component of the ventral grooved blubber (VGB) in fin whales are branches of cranial nerve VII (facial nerve). Therefore, the muscles of the VGB are homologous to second branchial arch derived muscles, which in humans include the muscles of "facial expression." We speculate, based on the presence of numerous foramina on the dorsolateral surface of the mandibular bones, that general sensation from the VGB likely is carried by branches of the mandibular division (V3) of cranial nerve V (trigeminal nerve), and that these small branches travel in the lipid-rich layer directly underlying the skin. We show that intercostal and phrenic nerves, which are not extensible, have a different wall and nerve core morphology than the large VGB nerves that are branches of VII. Although these VGB nerves are known to have two levels of waviness, the intercostal and phrenic nerves have only one in which the nerve fascicles in the nerve core are moderately wavy. In addition, the VGB nerves have inner and outer parts to their walls with numerous large elastin fibers in the outer part, whereas intercostal and phrenic nerves have single walls formed predominantly of collagen. Our results illustrate that overall nerve morphology depends greatly on location and the forces to which the structures are exposed. Anat Rec, 300:1963-1972, 2017. © 2017 Wiley Periodicals, Inc.

Effects of dimethylsulfoxide and pentoxifylline in the vitality of cutaneous flaps in rats.

to verify the influence of dimethylsulfoxide and pentoxifylline on the vitality of cutaneous flaps in rats and the tissue repair process. were studied 30 Wistar rats, submitting them to a 2cm wide by 8cm long dorsal cutaneous flap, of caudal base. We distributed the animals in three groups: Control Group (n=10) with application gauze moistened with 0.9% Saline in the flap bed for 30 seconds; Dimethylsulfoxide group (n=10), with administration of 1ml of 5% dimethylsulfoxide divided into five injections of 0.2ml in the transition of the flap segments; Pentoxifylline group (n=10), with administration of pentoxifylline 20mg/kg, diluted to 1ml and divided into five injections of 0.2ml in the transition of the flap segments. Drugs were administered intraoperatively, in a single dose and subcutaneously. We observed the skin flaps for changes in color and texture. On the 10th postoperative day, we checked the dimensions of viable and necrotic tissues, followed by excision of the specimen for histological analysis. the measurements of length of the viable and necrotic tissues between groups showed no differences. Histological analysis showed that the Dimethylsulfoxide group presented neovascularization, inflammatory infiltrate with leukocytes and more structured conjunctival stroma. The Pentoxifylline group showed neovascularization and inflammatory infiltrate, with moderate to intense granulation. The control group evolved with a higher rate of necrosis in the distal segment. dimethylsulfoxide and pentoxifylline influenced the vitality of the flap and the tissue repair process. However, they did not prevent necrosis macroscopically.

Comparison of Periodontal Biotypes Between Maxillary and Mandibular Anterior Teeth: A Clinical and Radiographic Study.

Periodontal biotype is a key element influencing esthetic treatment outcomes in clinical practice. However, while the soft and hard tissue thicknesses of maxillary anterior teeth have been widely studied, information regarding mandibular anterior teeth is scarce. Therefore, the aim of this study was to determine whether there is a relationship in terms of hard and soft tissue thickness between maxillary and mandibular anterior teeth. The present study included 90 maxillary and 90 mandibular anterior teeth in 15 healthy patients. Clinical and cone beam computed tomography measurements were taken to determine gingival and buccal bone thickness, respectively, and a correlation was made between maxillary and mandibular anterior teeth. No statistically significant differences were found when comparing gingival and buccal bone thickness at the crestal third and midpoint of maxillary and mandibular teeth (P > .05). However, some differences were observed at the apical third between the two groups. The results suggest that soft and hard tissue dimensions of maxillary and mandibular anterior teeth are comparable, especially in the coronal third. However, more studies are necessary to confirm that maxillary anterior teeth can be used as a reference when dealing with mandibular incisors and canines.

Short-term evaluation of tegumentary changes of the nose in oral breathers undergoing rapid maxillary expansion.

IntroductionRapid maxillary expansion is an orthodontic and orthopedic procedure that can change the form and function of the nose. The soft tissue of the nose and its changes can influence the esthetics and the stability of the results obtained by this procedure.ObjectiveThe objective of this study was to assess the changes in nose dimensions after rapid maxillary expansion in oral breathers with maxillary atresia, using a reliable and reproducible methodology through computed tomography.MethodsA total of 30 mouth-breathing patients with maxillary atresia were analyzed and divided into a treatment group who underwent rapid maxillary expansion (20 patients, 10 of which were male and 10 female, with a MA of 8.9 years and a SD of 2.16, ranging from 6.5 to 12.5 years) and a Control Group (10 patients, 5 of which were male and 5 female, with a MA of 9.2 years, SD of 2.17, ranging from 6.11 to 13.7 years). In the treatment group, multislice computed tomography scans were obtained at the start of the treatment (T1) and 3 months after expansion (T2). The patients of the control group were submitted to the same exams at the same intervals of time. Four variables related to soft tissue structures of the nose were analyzed (alar base width, alar width, height of soft tissue of the nose and length of soft tissue of the nose), and the outcomes between T1 and T2 were compared using Osirix MD software.ResultsIn the TG, the soft tissues of the nose exhibited significant increases in all variables studied (p < 0.05), whereas, changes did not occur in the control group (p > 0.05). In the treatment group, mean alar base width increased by 4.87% (p = 0.004), mean alar width increased by 4.04% (p = 0.004), mean height of the soft tissues of the nose increased by 4.84% (p = 0.003) and mean length of the soft tissues of the nose increased by 4.29% (p = 0.012).ConclusionIn short-term, rapid maxillary expansion provided a statistically significant increase in the dimensions of the soft tissues of the nose.

Lateral Cephalometric Linear Measurement Standards of Mongolian Children with Normal Occlusion from 6-7 Years of Age

Objectives: The aim of this study was to analyze craniofacial linear dimensions in subjects with normal occlusions to establish age and gender-specific lateral cephalometric linear measurement norms for Mongolian children. Methods: 161 six year old children and 122 seven year old children were recruited for this study. Digital cephalograms of 75 six year old children (34 male and 41female), 49 seven year old children (22 male and 27 female) were selected to establish lateral cephalometric linear measurement norms. Anatomic landmarks were identified directly on the digital images. The means and standard deviations of linear measurements were calculated using 18 variables. Student’s t-test was employed to test for gender differences in each age. Results: Anterior cranial base length and midfacial length were significantly larger in six year old male subjects. Mo-Ms and A-Ptm were significantly larger in seven year old male subjects. Conclusion: Our results showed that linear craniofacial dimension of the hard tissue was gender-dependent. Therefore, gender-specific differences of craniofacial distances should be taken into account during diagnosis and treatment planning. The results from this study can be used as reference values for 6-7 years old children of Mongolia.

Associations between mandibular symphysis form and craniofacial structures.

This study aimed to (1) analyze the relationships between mandibular symphysis characteristics (height, prominence, inclination, concavity, and convexity) and facial pattern, skeletal class, lower incisor position, and sex, and (2) determine the associations between the symphysis soft tissue dimensions and the underlying osseous structures. Cone-beam computed tomography (CBCT) images were selected for 385 patients (206 women and 179 men). The patients were classified according to their skeletal class and vertical pattern. The lower incisor inclination (IMPA) was recorded. Twelve measurements were taken for each mandibular symphysis using Invivo5 software (Anatomage, San Jose, CA, USA). Symphyseal measurements were larger in males than in females. Skeletal Class II and III hyperdivergent patients showed the highest symphysis height values. Hypodivergent individuals showed lower symphysis convexity angles. Concavity of the symphysis was greater for Class II hyperdivergent patients. Lower incisor inclination showed a positive correlation with symphysis concavity and inclination. Moderate and weak correlations were found between hard tissue and soft tissue parameters. Only a few characteristics of symphysis morphology depend on sex, incisor position, skeletal class, and vertical pattern. More significant relationships are found when the vertical pattern and skeletal class are analyzed in combination. The shape of the symphysis soft tissue is not directly correlated with the underlying skeletal structures.

Anatomic measures of upper airway structures in obstructive sleep apnea.

ObjectiveDetermine if anatomic dimensions of airway structures are associated with airway obstruction in obstructive sleep apnea (OSA) patients.MethodsTwenty-eight subjects with (n = 14) and without (n = 14) OSA as determined by clinical symptoms and sleep studies; volunteer sample. Skeletal and soft tissue dimensions were measured from radiocephalometry and magnetic resonance imaging. The soft palate thickness, mandibular plane-hyoid (MP-H) distance, posterior airway space (PAS) diameters and area, and tongue volume were calculated.ResultsCompared to controls, the OSA group demonstrated a significantly longer MP-H distance (P = 0.009) and shorter nasal PAS diameter (P = 0.02). The PAS area was smaller (P = 0.002) and tongue volume larger in the OSA group (P = 0.004). The MP-H distance, PAS measurements, and tongue volume are of clinical relevance in OSA patients.ConclusionsA long MP-H distance, and small PAS diameters and area are significant anatomic measures in OSA; however the most substantial parameter found was a large tongue volume.

Flow-Induced Vascular Network Formation and Maturation in Three-Dimensional Engineered Tissue.

Engineered three-dimensional (3D) constructs have received much attention as in vitro tools for the study of cell-cell and cell-matrix interactions, and have been explored for potential use as experimental models or therapeutic human tissue substitutes. Yet, due to diffusion limitations, the lack of stable and perfusable blood vessel networks jeopardizes cell viability once the tissue dimensions extend beyond several hundred microns. Direct perfusion of 3D scaffold cultures has been shown to enhance oxygen and nutrient availability. Additionally, flow-induced shear stress at physiologically relevant levels, positively impacted endothelial cell migration and alignment in various two-dimensional (2D) culture models and promoted angiogenic sprouting in microfluidic systems. However, little is known about the effect of flow on vascularization in implantable 3D engineered tissue models. The present study investigated the effect of direct flow-induced shear stress on vascularization in implantable 3D tissue. The differential effect of various levels of shear stress, applied while maintaining constant culture conditions, on vascular parameters was measured. Samples grown under direct flow conditions showed significant increases (>100%) in vessel network morphogenesis parameters and increases in vessel and extracellular matrix (ECM) protein depth distribution, as compared to those grown under static conditions. Enhanced vascular network morphogenesis parameters and higher colocalization of alpha-smooth muscle actin (α-SMA) with endothelial vessel networks characterized the specific contribution of direct flow to vessel network complexity and maturation. These observations suggest that flow conditions promote 3D neovascularization and may be advantageous in attempts to create large-volume, clinically relevant tissue substitutes.

An investigation of dimensional scaling using cervical spine motion segment finite element models.

The paucity of experimental data for validating computational models of different statures underscores the need for appropriate scaling methods so that models can be verified and validated using experimental data. Scaling was investigated using 50th percentile male (M50) and 5th percentile female (F05) cervical spine motion segment (C4-C5) finite element models subject to tension, flexion, and extension loading. Two approaches were undertaken: geometric scaling of the models to investigate size effects (volumetric scaling) and scaling of the force-displacement or moment-angle model results (data scaling). Three sets of scale factors were considered: global (body mass), regional (neck dimensions), and local (segment tissue dimensions). Volumetric scaling of the segment models from M50 to F05, and vice versa, produced correlations that were good or excellent in both tension and flexion (0.825-0.991); however, less agreement was found in extension (0.550-0.569). The reduced correlation in extension was attributed to variations in shape between the models leading to nonlinear effects such as different time to contact for the facet joints and posterior processes. Data scaling of the responses between the M50 and F05 models produced similar trends to volumetric scaling, with marginally greater correlations. Overall, the local tissue level and neck region level scale factors produced better correlations than the traditional global scaling. The scaling methods work well for a given subject, but are limited in applicability between subjects with different morphology, where nonlinear effects may dominate the response.

EFFECT OF PLATELET-RICH FIBRIN PALATAL BANDAGE ON PAIN SCORES AND WOUND HEALING AFTER FREE GINGIVAL GRAFT: A RANDOMIZED CONTROLLED CLINICAL TRIAL

Background: This prospective randomized clinical trial was conducted to determine whether the application of a platelet-rich fibrin (PRF) palatal bandage after harvesting free gingival grafts (FGG) would improve healing of donor sites and decrease pain scores and patient discomfort. Methods: Twenty-four patients received FGG to augment keratinized tissue dimensions. The application of a PRF bandage was decided randomly (n = 12 in each group). Patients reported their pain levels for the first 7 days of healing using the visual analog scale (VAS), 101-point numerical rating scale (NRS-101), and 4-point verbal rating scale (VRS-4). The patients’ pre-operative anxiety levels were measured using three anxiety scales. The healing of the donor sites was evaluated and compared to preoperative records. Data were assessed and recorded before surgery and at 1, 2, 3, 4, and 8 weeks postoperatively. Results: Dental anxiety, state-trait anxiety were evaluated at base line and correlated to the postoperative pain scores. There were no significant differences in anxiety levels between the two groups, yet they could potentially influence the outcome of any surgery and were included as covariates. The patients in the PRF group reported significantly lower pain scores and their pain levels returned to baseline levels earlier, compared to the control group. They were also assessed as having better wound healing over a 2-month follow-up period, based on color, contour, and texture indices. Conclusion: PRF palatal bandages significantly reduced postoperative pain and discomfort, and facilitated wound healing after harvesting FGG.

Assessment of gingival biotype and facial hard/soft tissue dimensions in the maxillary anterior teeth region using cone beam computed tomography

ObjectiveThis study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT). DesignThis study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2mm apical to the gingival margin was measured and GT <1.5mm was categorized as thin while GT ≥1.5mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane’s Q, chi-square and independent samples t-tests. ResultsThe BT around the maxillary central and lateral incisors and canine teeth at 4 and 6mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P<0.05). The mean GT at 2 and 4mm apical to the CEJ was significantly different around central and lateral incisors (P<0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P<0.05). ConclusionThe two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.