3-dimensional Laser Scanning Research Articles

Patient-Specific Distal Femoral Guides Optimize Cartilage Topography Matching in Osteochondral Allograft Transplantations

Background: Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching. Purpose: To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model. Study Design: Descriptive laboratory study. Methods: Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured. Results: The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm. Conclusion: These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching. Clinical Relevance: Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources.

Effects of surface treatment and shade on the color, translucency, and surface roughness of high-translucency self-glazed zirconia materials

Statement of problemThe impact of different surface treatments and shades on the color, translucency, and surface roughness of high-translucency self-glazed zirconia materials is unclear. PurposeThe purpose of this in vitro study was to investigate the effects of different external surface treatments (self-glazed, milled, polished, and glazed), intaglio surface treatments (milled and airborne-particle abraded), and shades (A1 and A3 shades) on the color, translucency, and surface roughness of high-translucency self-glazed zirconia materials, as well as the correlations among optical parameters, translucency, and surface roughness. Material and methodsEighty shade A1 and 80 shade A3 disks were fabricated with a thickness of 0.80 ±0.02 mm and divided into 16 groups (n=10). Different external and intaglio surface treatments were applied to the specimens. CIELab values were measured with a spectrophotometer, and color differences (ΔE00) and relative translucency parameter (RTP) were calculated. Total transmittance (Tt%) and reflectance (R%) were tested with a spectrophotometer equipped with an integrating sphere. Surface roughness (Ra and Rz) (μm) was measured with a noncontact 3-dimensional laser scanning microscope. One specimen from each group was subjected to scanning electron microscope (SEM) examination. Data were analyzed with ANOVA and the Tukey post hoc test. The correlation among optical parameters, translucency, and surface roughness was investigated by using Pearson correlation analysis (α=.05). ResultsThe effects of external surface treatments, intaglio airborne-particle abrasion, and shades on ΔE00, RTP, and Ra values of the disks were significantly different (P<.001). The smoothest external polishing surface had the greatest RTP and color difference (P<.001). Shade A3 disks had lower RTP and Tt% values than shade A1 disks (P<.001). ΔE00 had a highly positive relationship with the RTP (A1: r=0.884, P<.001; A3: r=0.859, P<.001). SEM images demonstrated that surface treatments affected the surface texture of monolithic zirconia ceramics. ConclusionsDifferent surface treatments affected the surface roughness, translucency, and final color of zirconia materials. The smoothest external polishing surface had the greatest RTP and color difference. Different shades influenced the translucency, as the darker the disk shade, the lower the translucency. The RTP was appropriate as an auxiliary indicator for evaluating the color of a dental ceramic.

MDP Salts: A New Bonding Strategy for Zirconia

Durable resin-ceramic adhesion may influence the clinical success of ceramic restorations, which has been one of the challenging issues in dentistry. The present study assessed the bond strength and chemical interaction of 10-methacryloxydecyl dihydrogen phosphate (MDP), MDP+silane, and MDP-salt primers to alumina-blasted zirconia ceramic by tensile bond strength test, surface elemental composition with x-ray photoelectron spectroscopy analysis, contact angle measurement, surface morphology with scanning electron microscopy, and surface topography with 3-dimensional confocal laser scanning microscope analyses. MDP-salt showed the highest tensile bond strength before and after thermocycling when compared with MDP and MDP+silane (P < 0.05). The measured contact angle values differed significantly (P < 0.001) in the order of MDP-salt > control (no chemical pretreatment) > MDP+silane > MDP. There was no difference in surface roughness (P = 0.317) and surface topography among all tested groups. Zirconia treated with MDP-salt showed phosphorus peaks in addition to zirconia and alumina peaks. MDP-salt has zirconia priming properties, which improves bonding performance to resin cement.

Reconsidering cell-assisted lipotransfer for breast augmentation: effect of stromal vascular fraction enrichment on graft survival assessed with 3-dimensional laser scanning

Reconsidering cell-assisted lipotransfer for breast augmentation: effect of stromal vascular fraction enrichment on graft survival assessed with 3-dimensional laser scanning

Long-term Outcomes of Temporal Hollowing Augmentation by Targeted Volume Restoration of Fat Compartments in Chinese Adults.

Previous anatomical and clinical studies have suggested that targeted restoration of the volume and distribution of fat compartments using appropriate cannula entry sites and injection planes is an excellent fat-grafting technique for facial contouring and hand rejuvenation. To perform subjective and objective evaluations of the safe and effective profile of the targeted fat-grafting technique for temporal hollowing augmentation. In a retrospective cohort study, a total of 96 consecutive patients with temporal hollowing were treated at the Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai, China, with the targeted fat-grafting technique from January 1, 2009, to January 1, 2017. The safety and efficacy profile of this technique was evaluated by the following methods: (1) a quantitative measurement of fat-graft survival and temporal augmentation rates by using 3-dimensional laser scanning, (2) a subjective assessment using a satisfaction survey and the Hollowness Severity Rating Scale (grades range from 0-3, with higher grades representing more hollowness), and (3) the complication rate. Of the 96 study patients, 94 (97.9%) were women and the mean (SD) age was 34.4 (7.4) years. Of the 142 autologous fat-grafting procedures performed, the mean (SD) total follow-up time was 16.3 (3.2) months, with a mean (SD) of 1.5 (0.7) procedures performed. The mean (SD) baseline volume requirement per temple for each patient was 12.8 (4.8) mL, and the total volume of the fat graft per temple was 17.8 (7.5) mL. Quantitative analysis revealed that the mean (SD) total augmentation volume per temple was 11.7 (3.0) mL, the total survival rate of the fat grafts was 65.7% (12.6%), and total augmentation rate of hollowness was 91.4% (23.4%). Subjective analysis revealed that all patients showed an improved appearance after fat grafting, and 142 temples (74.0%) exhibited clinical improvement by more than 2 grades. In all, 88 patients (91.7%) were satisfied with the outcomes, with a low complication rate reported. The targeted fat-grafting technique allows the transplant of fat tissue into 4 separate fat compartments in a double-plane manner through a unique cannula entry site that avoids severe neurovascular injury. The long-term results demonstrate that this technique is an effective, reproducible, and safe approach for temporal hollowing augmentation. 4.

Inhibition of Enterococcus faecalis Growth and Biofilm Formation by Molecule Targeting Cyclic di-AMP Synthetase Activity

IntroductionEnterococcus faecalis is correlated with oral diseases including recurrent root canal treatment failure because of its biofilm formation ability and various virulence factors. Cyclic di-AMP (c-di-AMP) is an omnipresent second messenger involved in many crucial cellular physiological processes, including biofilm formation. ST056083 is a small molecule working as an inhibitor of the c-di-AMP synthetase DNA integrity scanning protein (DisA) in vitro. In this study, the impact of ST056083 on E. faecalis DisA activity, bacterial growth, and biofilm formation was tested. MethodsThe binding affinity between the protein and ligand was evaluated using the Amber score, and the binding mode was analyzed and visualized using UCSF Chimera (Resource for Biocomputing, Visualization, and Informatics, University of California, San Francisco, San Francisco, CA). The effect of ST056083 on E. faecalis DisA was evaluated using the coralyne assay. The effect of ST056083 on E. faecalis biofilm formation was determined by the biofilm quantification assay, scanning electron microscopic examination, and 3-dimensional confocal laser scanning microscopic assay. The effect of ST056083 on E. faecalis exopolysaccharide synthesis was measured by the anthrone-sulfuric method. ResultsWe expressed and purified E. faecalis DisA in vitro and confirmed the inhibitory effect of ST056083 on its biological activity. In addition, we showed the inhibitory effect of ST056083 on E. faecalis growth, biofilm formation, and exopolysaccharide synthesis. ConclusionsOur findings enhance the understanding of the physiological role of c-di-AMP in E. faecalis and represent a preliminary study on the ST056083 inhibitory effect and mechanism.

A pilot study comparing custom contoured and planar support surfaces for pressure ulcer risk over the heels for night time postural management using interface pressure mapping and discomfort scores

PurposeCustom contouring techniques are effective for reducing pressure ulcer risk in wheelchair seating. These techniques may assist the management of pressure ulcer risk during sleep for night time postural management. ObjectivesTo investigate the effectiveness of custom contoured night time postural management components against planar support surfaces for pressure ulcer risk measures over the heels. MethodSupine posture was captured from five healthy participants using vacuum consolidation and 3-dimensional laser scanning. Custom contoured abduction wedges were carved from polyurethane and chipped foams. Pressure mapping and the visual analog scale were used to evaluate the effectiveness of the contoured foams in reducing pressure and discomfort under the posterior heel against standard planar support surfaces. ResultsCustom contoured shapes significantly reduced interface pressures (p < 0.05) and discomfort scores (p < 0.05) when compared to planar support surfaces. Polyurethane foam was the most effective material but it did not differ significantly from chipped foam. Linear regression revealed a significant relationship between the Peak Pressure Index and discomfort scores (r = 0.997, p = 0.003). ConclusionsThe findings of this pilot study suggested that custom contoured shapes were more effective than planar surfaces at reducing pressure ulcer risk surrogate measures over the posterior heels with polyurethane foam being the most effective material investigated. It is recommended that Evazote foam should not be used as a support surface material for night time postural management.

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography.

PurposeThe aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement.Materials and MethodsThirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability.ResultsThe root surface area measurements (230.11±41.97 mm2) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT.ConclusionThis study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

Characterizing microscale aluminum composite layer properties on silicon solar cells with hybrid 3D scanning force measurements.

This article presents a novel technique to estimate the mechanical properties of the aluminum composite layer on silicon solar cells by using a hybrid 3-dimensional laser scanning force measurement (3-D LSFM) system. The 3-D LSFM system measures the material properties of sub-layers constituting a solar cell. This measurement is critical for realizing high-efficient ultra-thin solar cells. The screen-printed aluminum layer, which significantly affects the bowing phenomenon, is separated from the complete solar cell by removing the silicon (Si) layer with deep reactive ion etching. An elastic modulus of ~15.1 GPa and a yield strength of ~35.0 MPa for the aluminum (Al) composite layer were obtained by the 3-D LSFM system. In experiments performed for 6-inch Si solar cells, the bowing distances decreased from 12.02 to 1.18 mm while the Si layer thicknesses increased from 90 to 190 μm. These results are in excellent agreement with the theoretical predictions for ultra-thin Si thickness (90 μm) based on the obtained Al composite layer properties.

A novel method for high-throughput detection and quantification of neutrophil extracellular traps reveals ROS-independent NET release with immune complexes.

A newly-described first-line immune defence mechanism of neutrophils is the release of neutrophil extracellular traps (NETs). Immune complexes (ICxs) induce low level NET release. As such, the in vitro quantification of NETs is challenging with current methodologies. In order to investigate the role of NET release in ICx-mediated autoimmune diseases, we developed a highly sensitive and automated method for quantification of NETs. After labelling human neutrophils with PKH26 and extracellular DNA with Sytox green, cells are fixed and automatically imaged with 3-dimensional confocal laser scanning microscopy (3D-CLSM). NET release is then quantified with digital image analysis whereby the NET amount (Sytox green area) is corrected for the number of imaged neutrophils (PKH26 area). A high sensitivity of the assay is achieved by a) significantly augmenting the area of the well imaged (11%) as compared to conventional assays (0.5%) and b) using a 3D imaging technique for optimal capture of NETs, which are topologically superimposed on neutrophils. In this assay, we confirmed low levels of NET release upon human ICx stimulation which were positive for citrullinated histones and neutrophil elastase. In contrast to PMA-induced NET release, ICx-induced NET release was unchanged when co-incubated with diphenyleneiodonium (DPI). We were able to quantify NET release upon stimulation with serum from RA and SLE patients, which was not observed with normal human serum. To our knowledge, this is the first semi-automated assay capable of sensitive detection and quantification of NET release at a low threshold by using 3D CLSM. The assay is applicable in a high-throughput manner and allows the in vitro analysis of NET release in ICx-mediated autoimmune diseases.

Evaluation of Bone Healing After Osteotomies Prepared With Er:YAG Laser in Contact and Noncontact Modes and Piezosurgery—An Animal Study

To analyze the healing of bone tissue treated with Er:YAG laser contact and noncontact modes of and piezosurgery in a rat model using triangular laser profilometry. Twenty-four 10-week-old adult male Wistar rats were used in the study. Three osteotomies on the medial part of tibia were performed in each animal, 1 in the right tibia and 2 in the left tibia. The osteotomies were performed with a piezoelectric device set at maximal power and the Er:YAG laser in contact mode (power, 7.5 W; pulse energy, 375 mJ; repetition rate, 20 Hz; MSP mode) and noncontact mode (power, 7.5 W; pulse energy, 750 mJ; repetition rate, 10 Hz; QSP mode) with a novel type of circular, digitally controlled handpiece (x-Runner). After surgery, 6 animals were immediately euthanized (group 1), and the others were euthanized after 1 week (group 2, n = 6), 2 weeks (group 3, n = 6), and 3 weeks (group 4, n = 6). Bone healing after osteotomy was analyzed using a 3-dimensional laser scanning technique (ie, laser triangulation profilometry). The volume reduction rates are similar for all 3 techniques (0.2 to 0.25 mm(3) per week). Greater volume reduction of 0.25 mm3 per week was observed for the Er:YAG laser in noncontact mode (x-Runner). After 3 weeks, almost complete healing of the prepared osteotomy was observed. Within the limitations of this study, the osteotomies performed by the Er:YAG laser in digitally controlled noncontact mode healed the fastest.

Reconstructing DEM using TLS point cloud data and NURBS surface

Underground coal mining inevitably results in land surface subsidence. Acquiring information on land surface subsidence is important in the detection of surface change. However, conventional data acquisition techniques cannot always retrieve information on whole subsidence area. This study focuses on the reconstruction of a digital elevation model (DEM) with terrestrial laser scanning (TLS) point cloud data. Firstly, the methodology of the DEM with terrestrial 3-dimensional laser scanning is introduced. Then, a DEM modeling approach that involves the application of curved non-uniform rational B-splines (NURBS) surface is put forward. Finally, the performance of the DEM modeling approach with different surface inverse methods is demonstrated. The results indicate that the DEM based on the point cloud data and curved NURBS surface can achieve satisfactory accuracy. In addition, the performance of the hyperbolic paraboloid appears to be better than that of the elliptic paraboloid. The reconstructed DEM is continuous and can easily be integrated into other programs. Such features are of great importance in monitoring dynamic ground surface subsidence.

Effect of a second injection of botulinum toxin on lower facial contouring, as evaluated using 3-dimensional laser scanning.

Botulinum toxin type A (BoNT-A) is widely used to improve the lower facial contour. To determine the difference in the changes in the lower facial contour achieved with 1 and 2 sessions of BoNT-A injections using 3-dimensional (3D) laser scanning. Twenty volunteers were randomly divided into 2 groups. Group I (n = 10) received a single injection, whereas Group II (n = 10) received 2 sessions of injections, the second being administered 4 months after the first. Each injection comprised of 25 U of BoNT-A and was administered to the masseter muscle bilaterally. Evaluation of the effect of BoNT-A injection was performed using 3D laser scan images obtained before the injection and 6 months thereafter in Group I, and before the first injection and 6 months thereafter in the Group II. The mean changes in the volume and thickness in Group I were -1,186 mm and -1.52 mm, respectively; the corresponding changes were -4,072 mm and -3.84 mm in Group II. The reductions were significantly greater in Group II than in Group I. The administration of a second BoNT-A injection is effective for better aesthetic results for the lower facial contour.

Commentary on Effect of a second injection of botulinum toxin on lower facial contouring, as evaluated using 3-dimensional laser scanning.

Commentary on Effect of a second injection of botulinum toxin on lower facial contouring, as evaluated using 3-dimensional laser scanning.

Quantitative analysis of variable extent of anterior clinoidectomy with intradural and extradural approaches: 3-dimensional analysis and cadaver dissection.

Drilling of the anterior clinoid process (ACP) is an integral component of surgical approaches for central and paracentral skull base lesions. The technique to drill ACP has evolved from pure intradural to extradural and combined techniques. To describe the computerized morphometric evaluation of exposure of optic nerve and internal carotid artery with proposed tailored intradural (IDAC) and complete extradural (EDAC) anterior clinoidectomy. We describe a morphometric subdivision of ACP into 4 quadrangles and 1 triangle on the basis of fixed bony landmarks. Computerized volumetric analysis with 3-dimensional laser scanning of dry-drilled bones for respective tailored IDAC and EDAC was performed. Both approaches were compared for the area and length of the optic nerve and internal carotid artery. Five cadaver heads were dissected on alternate sides with intradural and extradural techniques to evaluate exposure, surgical freedom, and angulation of approach. Complete anterior clinoidectomy provides a 2.5-times larger area and 2.7-times larger volume of ACP. Complete clinoidectomy deroofed the optic nerve to an equal extent as by proposed the partial tailored clinoidectomy approach. Tailored IDAC exposes only the distal dural ring, whereas complete EDAC exposes both the proximal and distal dural rings with complete exposure of the carotid cave. Quantitative comparative evaluation provides details of exposure and surgical ease with both techniques. We promote hybrid/EDAC technique for vascular pathologies because of better anatomic orientation. Extradural clinoidectomy is the preferred technique for midline cranial neoplasia. An awareness of different variations of clinoidectomy can prevent dependency on any particular approach and facilitate flexibility.

Reprogramming of fibroblast nuclei in cloned bovine embryos involves major structural remodeling with both striking similarities and differences to nuclear phenotypes of in vitro fertilized embryos

Nuclear landscapes were studied during preimplantation development of bovine embryos, generated either by in vitro fertilization (IVF), or generated as cloned embryos by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts, using 3-dimensional confocal laser scanning microscopy (3D-CLSM) and structured illumination microscopy (3D-SIM). Nuclear landscapes of IVF and SCNT embryonic nuclei were compared with each other and with fibroblast nuclei. We demonstrate that reprogramming of fibroblast nuclei in cloned embryos requires changes of their landscapes similar to nuclei of IVF embryos. On the way toward the 8-cell stage, where major genome activation occurs, a major lacuna, enriched with splicing factors, was formed in the nuclear interior and chromosome territories (CTs) were shifted toward the nuclear periphery. During further development the major lacuna disappeared and CTs were redistributed throughout the nuclear interior forming a contiguous higher order chromatin network. At all stages of development CTs of IVF and SCNT embryonic nuclei were built up from chromatin domain clusters (CDCs) pervaded by interchromatin compartment (IC) channels. Quantitative analyses revealed a highly significant enrichment of RNA polymerase II and H3K4me3, a marker for transcriptionally competent chromatin, at the periphery of CDCs. In contrast, H3K9me3, a marker for silent chromatin, was enriched in the more compacted interior of CDCs. Despite these striking similarities, we also detected major differences between nuclear landscapes of IVF and cloned embryos. Possible implications of these differences for the developmental potential of cloned animals remain to be investigated. We present a model, which integrates generally applicable structural and functional features of the nuclear landscape.

Submorphotypes of the maxillary first molar and their effects on alignment and rotation

The aim of this study was to explore the shape differences in maxillary first molars with orthographic measurements using 3-dimensional virtual models to assess whether there is variability in morphology that could affect the alignment results when treated by straight-wire appliance systems. A total of 175 maxillary first molars with 4 cusps were selected for classification. With 3-dimensional laser scanning and reconstruction software, virtual casts were constructed. After performing several linear and angular measurements on the virtual occlusal plane, the teeth were clustered into 2 groups by the method of partitioning around medoids. To visualize the 2 groups, occlusal polygons were constructed using the average data of these groups. The resultant 2 clusters showed statistically significant differences in the measurements describing the cusp locations and the buccal and lingual outlines. The rotation along the centers made the 2 cluster polygons look similar, but there was a difference in the direction of the midsagittal lines. There was considerable variability in morphology according to 2 clusters in the population of this study. The occlusal polygons showed that the outlines of the 2 clusters were similar, but the midsagittal line directions and inner geometries were different. The difference between the morphologies of the 2 clusters could result in occlusal contact differences, which might be considered for better alignment of the maxillary posterior segment.

New method for sperm evaluation by 3-dimensional laser scanning microscopy in different laboratory animal species.

Sperm analysis is one of the end points in reproductive toxicology studies. Different methods for quantitative sperm analysis have been described. For qualitative morphological sperm analysis, either such techniques or smears of sperm and histological sperm staging are in use. Any of these methods provides morphological results on a light microscopy level. Laser scanning microscopy is a technique using a focused laser for scanning an object. The Olympus 3D Laser Scanning Microscope LEXT OLS4000 with optional possibilities of differential interference contrast provides a microscopic method for visualizing microasperities, which are far beyond the resolving power of a typical light or laser microscope. This technique was applied to sperm of mice, rats, rabbits, and cynomolgus monkeys at magnifications up to ×17 090. The obtained images are comparable to those of a scanning electron microscope under relatively low-power magnifications. Measurements on sperm parameters were taken by an integrated image analysis software tool. Abnormalities were easily detectable.

Matching Articular Surfaces of Selected Donor and Recipient Sites for Cylindrical Osteochondral Grafts of the Femur

Background: Autogenous osteochondral grafting has been widely performed as a treatment for focal osteochondral defects. In this procedure, it is important to match the shape of the articular surface between the donor site and recipient site to reproduce the original articular surface of the femur. Purpose: To investigate the ideal matching patterns of articular surface profiles of donor and recipient sites for autogenous osteochondral grafting of the femur using a 3-dimensional laser scanning method. Study Design: Descriptive laboratory study. Methods: The donor and recipient sites in 11 cadaveric knees were examined, and each of the sites was divided into 12 areas. In the donor sites, the contours of the articular surface of the medial and lateral femoral trochleae were determined. In the recipient sites, the contours of the articular surface of the medial and lateral femoral condyles were assessed. Vertical intervals (VIs) were then calculated as the parameter for the height of the articular surface. The VI was the height difference from the highest and lowest points in the contours of the articular surface within the area of the donor and recipient sites. Finally, assessments were made on whether the articular surface of the donor and recipient sites matched properly for cylindrical osteochondral grafts with diameters of 6, 8, and 10 mm. Results: For the donor site, the VIs of the middle area of the femoral trochlea were significantly smaller than those of the peripheral area. For the recipient site, the VIs of the anterior area of the femoral condyle were significantly smaller than those of the posterior area. Conclusion: These results indicated in aging specimens that the articular surface profile of the middle area of the donor site matched that of the anterior area of the recipient site. On the other hand, the shape of the articular surface of the peripheral area of the donor site was congruent with that of the posterior area of the recipient site. Clinical Relevance: This study will be useful for improving donor site selection during preoperative planning. The authors recommend selection of the middle area of the femoral trochlea for cartilage defects in the anterior area of the femoral condyle and of the peripheral area of the femoral trochlea for cartilage defects in the posterior area of the femoral condyle.

Predicting tooth-size discrepancy: A new formula utilizing revised landmarks and 3-dimensional laser scanning technology

The goal of this study was to develop a more accurate formula to forecast tooth-size discrepancies in patients based on not only the size of the whole teeth but also functional arch components derived from normal cusp-fossa interdigitation that should be obtained as the final treatment goal. A total of 141 dental casts from Dr Larry Andrews' collection of "normal occlusions" that never received orthodontic treatment were scanned with an Ortho Insight 3D Laser Scanner (Motion View Software, Chattanooga, Tenn). Individual tooth sizes and portions of tooth sizes were measured with the Motion View Software. For each set of models, potential tooth-size discrepancies were calculated by using both the original Bolton analysis and the new Johnson/Bailey analysis developed by this team at the University of California at San Francisco (UCSF). Six tooth-size discrepancy ratios were computed and included the Bolton (2) and the new (4) Johnson/Bailey analysis ratios for the anterior arch component, posterior arch component, and overall ratio of the maxillary and mandibular arches. The Johnson/Bailey analysis utilized different landmarks and groups of teeth. It consequently divided the maxillary segment by the mandibular segment, in contrast to the Bolton ratios, which divided the mandibular sums by the maxillary totals. The Bolton anterior segment ratio ranged from 70.68 to 84.81, with a mean of 77.91 (SD, 2.43) (3.1%). The Bolton overall ratio ranged from 86.19 to 96.62, with a mean of 91.64 (SD, ±1.74) (1.8%). The Johnson/Bailey posterior discrepancy ratio ranged from 0.98 to 1.23, with a mean of 1.10 (SD, ±0.04) (3.6%). Its anterior discrepancy ratio ranged from 0.91 to 1.14, with a mean of 1.03 (SD, ±0.04) (3.9%). The Johnson/Bailey overall discrepancy ratio ranged from 0.98 to 1.15, with a mean of 1.06 (SD, ±0.03) (2.8%). Two methods were used to forecast tooth-size discrepancies between opposing arches in a sample with clinically acceptable occlusions. The new approach provided more specific ratios utilizing more clinically relevant functional archcomponents derived from dental cusp-fossa interdigitation.