RESUMEN
The purpose of this study was to examine and compare the reproducibility and reliability of digitization using Dolphin Imaging Software (Version 8.0) with traditional manual techniques. In addition, orthognathic prediction was compared with actual outcomes. Sixty lateral cephalograms were evaluated by two methods: manual tracing and indirect digitization using Dolphin Imaging Software (Version 8.0). Method error (reliability) using duplicate measurements for each method, and comparison of both techniques (reproducibility), were investigated using alternative statistical methods, Bland and Altman (1986) and Lin's Correlation of Concordance (1989). Each technique was significantly reliable at the 95% level (method error). Comparing the standard deviations of the differences, manual tracing proving more reliable for SNA (1.36 degrees manually, 2.07 degrees digitally), SNB (1.19 degrees and 1.69 degrees ), SNMx (1.39 degrees and 2.66 degrees ), and MxMd (1.77 degrees and 2.26 degrees ), and Dolphin digital tracing more reliable for UIMx (3.49 degrees digitally and 3.97 degrees manually) and LIMd (2.90 degrees and 3.04 degrees ). However, systematic error in the software's calculation of LAFH% resulted in measurements 4% larger than manual techniques, a difference which is clinically significant. Comparison of actual outcome and software generated prediction for 26 orthognathic cases demonstrated clinically significant differences for all measurements (rhoc 0.32 for ANB to 0.91 for LIMd; P<0.05). The investigation revealed the impact of radiographic magnification when used in an uncalibrated system. These findings indicate that Version 8.0 of Dolphin Imaging Software needs to be re-assessed for software errors that may result in clinically significant miscalculations, and to facilitate compensation of radiographic magnification when using linear measurements.
Asunto(s)
Cefalometría/estadística & datos numéricos , Diagnóstico por Computador/métodos , Intensificación de Imagen Radiográfica/métodos , Validación de Programas de Computación , Humanos , Pronóstico , Magnificación Radiográfica , Reproducibilidad de los Resultados , Cirugía BucalRESUMEN
The aims of this study were to identify the role and sites of action of serine proteinases (SPs) in bone resorption, a process which involves a cascade of events, the central step of which is the removal of bone matrix by osteoclasts (OCs). This resorbing activity, however, is also determined by recruitment of new OCs to future resorption sites and removal of the osteoid layer by osteoblasts (OBs), which enables OCs to gain access to the underlying mineralized bone. The resorption systems we have studied consisted of (i) neonatal calvarial explants, (ii) isolated OCs cultured on ivory slices, (iii) mouse OBs cultured on either radiolabelled type I collagen films or bone-like matrix, (iv) bone marrow cultures to assess OC formation and (v) 17-day-old fetal mouse metatarsal bone rudiments to assess OC migration and fusion. Two separate SP inhibitors, aprotinin and alpha(2)-antiplasmin dose-dependently inhibited (45)Ca release from neonatal calvarial explants: aprotinin (10(-6) M) was the most effective SP inhibitor, producing a maximum inhibitory effect of 55.9%. Neither of the SP inhibitors influenced either OC formation or OC resorptive activity. In contrast, each SP inhibitor dose-dependently inhibited OB-mediated degradation of both type I collagen fibrils and non-mineralized bone matrix. In 17-day-old metatarsal explants aprotinin produced a 55% reduction in the migration of OCs from the periosteum to the mineralized matrix after 3 days in culture but after 6 days in culture aprotinin was without effect on OC migration. Primary mouse osteoblasts expressed mRNA for urokinase type plasminogen activator (uPA), tIssue type plasminogen activator (tPA), the type I receptor for uPA, plasminogen activator inhibitor types I and II and the broad spectrum serine proteinase inhibitor, protease nexin I. In situ hybridization demonstrated expression of tPA and uPA in osteoclasts disaggregated from 6-day-old mouse long bones. We propose that the regulation of these various enzyme systems within bone tIssue determines the sites where bone resorption will be initiated.
Asunto(s)
Resorción Ósea/metabolismo , Huesos/fisiología , Inhibidores de Serina Proteinasa/farmacología , Precursor de Proteína beta-Amiloide , Animales , Animales Recién Nacidos , Aprotinina/farmacología , Células de la Médula Ósea , Huesos/efectos de los fármacos , Proteínas Portadoras/genética , Células Cultivadas , Técnicas de Cultivo , Relación Dosis-Respuesta a Droga , Expresión Génica , Ratones , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Osteoclastos/efectos de los fármacos , Osteoclastos/metabolismo , Inhibidor 1 de Activador Plasminogénico/genética , Inhibidor 2 de Activador Plasminogénico/genética , Nexinas de Proteasas , Receptores de Superficie Celular/genética , Receptores del Activador de Plasminógeno Tipo Uroquinasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Activador de Tejido Plasminógeno/genética , Activador de Plasminógeno de Tipo Uroquinasa/genética , alfa 2-Antiplasmina/farmacologíaRESUMEN
Sex steroids are important regulators of bone cell function and osteoblast-derived matrix metalloproteinases (MMPs) are key mediators of bone resorption during the initial stage of osteoid removal prior to osteoclast attachment. To investigate the mechanism of bone loss following estrogen deficiency, we examined the effects of estrogen on osteoblast synthesis of MMPs and tissue inhibitor of metalloproteinases (TIMPs). Immunolocalization in mouse bone samples ex vivo and primary mouse osteoblast (MOB) cultures was used to document the synthesis of mouse interstitial collagenase (MMP-13), stromelysin-1 (MMP-3), gelatinase-A (MMP-2), and gelatinase-B (MMP-9). Endosteal bone lining cells from distal femoral head and lumbar vertebral body showed an increase in the pattern of synthesis of stromelysin-1 following ovariectomy, compared with sham-operated controls; the synthesis of other MMPs was unaffected. The expression of all classes of MMPs and TIMP-1 and TIMP-2 by MOB in culture was demonstrated by reverse transcriptase-polymerase chain reaction. Following the withdrawal of 17beta-estradiol, MOB cultures showed a significant increase in the number of cells synthesizing stromelysin-1; this effect was enhanced by stimulation with either interleukin-1 or interleukin-6. Northern blot analysis showed only a slight increase in stromelysin-1 mRNA message following the withdrawal of 17beta-estradiol. Our data show an unexpected up-regulation of stromelysin-1 synthesis by osteoblasts both in vivo and in vitro following estrogen withdrawal. Although this effect was not reflected in a significant change in stromelysin-1 mRNA expression in vitro, there is evidence to suggest a role for this enzyme in the early stages of bone loss during the pathogenesis of osteoporosis.
Asunto(s)
Estrógenos/metabolismo , Metaloproteinasa 3 de la Matriz/biosíntesis , Osteoblastos/metabolismo , Regulación hacia Arriba , Animales , Northern Blotting/métodos , Células Cultivadas , Colagenasas/análisis , Colagenasas/genética , Cabeza Femoral/citología , Cabeza Femoral/patología , Vértebras Lumbares/citología , Vértebras Lumbares/patología , Metaloproteinasa 2 de la Matriz/análisis , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 3 de la Matriz/análisis , Metaloproteinasa 3 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/análisis , Metaloproteinasa 9 de la Matriz/genética , Ratones , Osteoblastos/citología , Ovariectomía , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Inhibidor Tisular de Metaloproteinasa-1/genética , Inhibidor Tisular de Metaloproteinasa-2/genéticaRESUMEN
Connective tissue cells synthesize and secrete matrix metalloproteinases (MMPs), a family of matrix-degrading enzymes (comprising collagenases, gelatinases and stromelysins), which are capable of degrading all the constituent molecules of connective tissues at physiological pH. This investigation documents the synthesis and distribution of MMPs and their inhibitor TIMP-1 (tissue inhibitor of metalloproteinases-1) in the developing articular disc of the craniomandibular joint of the rabbit using indirect immunofluorescence microscopy. Cells of the disc synthesised all three classes of MMPs as well as TIMP-1 in all regions of the disc at all stages examined. MMPs and TIMP-1 were detected as bright intracellular accumulations probably within Golgi vesicles and as occasional diffuse, matrix-bound deposits. These results suggest that MMP-mediated matrix remodelling is a prominent feature of growth in craniomandibular joint disc.
Asunto(s)
Cartílago Articular/enzimología , Glicoproteínas/metabolismo , Metaloendopeptidasas/biosíntesis , Inhibidores de Proteasas/metabolismo , Articulación Temporomandibular/enzimología , Animales , Cartílago Articular/crecimiento & desarrollo , Colagenasas/análisis , Colagenasas/biosíntesis , Matriz Extracelular/enzimología , Técnica del Anticuerpo Fluorescente Indirecta , Gelatinasas/análisis , Gelatinasas/biosíntesis , Glicoproteínas/análisis , Metaloproteinasa 3 de la Matriz , Metaloendopeptidasas/análisis , Metaloendopeptidasas/antagonistas & inhibidores , Microscopía Fluorescente , Inhibidores de Proteasas/análisis , Conejos , Articulación Temporomandibular/crecimiento & desarrollo , Inhibidores Tisulares de MetaloproteinasasRESUMEN
BACKGROUND: The matrix metalloproteinases (MMPs) are a family of closely related enzymes, the principal members being the collagenases, gelatinases, and stromelysins. They are synthesized and secreted by connective tissue cells and are capable of degrading all the components of connective tissue matrices at physiological pH. METHODS: Patterns of synthesis and distribution of MMPs and their inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1), are documented in the craniofacial region at sites of bone formation during both intramembranous (e.g., calvaria, maxilla, and mandible) and endochondral ossification (e.g., cartilaginous cranial base and synchondroses) using indirect immunolocalization. RESULTS: MMPs and TIMP-1 were detected both as bright intracellular accumulations, indicating active synthesis, and as diffuse matrix-bound extracellular deposits. Gelatinase-A had an extensive distribution in osteogenic tissues and was detected both in cells of the periosteum and spongiosum and as extracellular deposits in the osteoid layer of newly formed bone. In addition, gelatinase-AB synthesis was detected in osteoclasts. All regions of the early cartilaginous cranial base produced MMPs and TIMP-1, and synthesis continued in the established synchondrosis. MMPs and TIMP-1 were also documented in early tooth germs and in Meckel's cartilage. CONCLUSIONS: These data document a prominent role for MMPs, and in particular gelatinase-A, in mediating matrix degradation during osteogenesis. Their detection in tooth germs and Meckel's cartilage further indicates a role for MMPs and TIMP-1 in matrix turnover during morphogenesis.
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Huesos Faciales/embriología , Huesos Faciales/metabolismo , Glicoproteínas/metabolismo , Metaloendopeptidasas/metabolismo , Cráneo/embriología , Cráneo/metabolismo , Animales , Colagenasas/metabolismo , Femenino , Técnica del Anticuerpo Fluorescente , Gelatinasas/metabolismo , Metaloproteinasa 3 de la Matriz , Osteogénesis , Embarazo , Conejos , Inhibidores Tisulares de MetaloproteinasasRESUMEN
Connective tissues synthesise and secrete a family of matrix metalloproteinases (MMPs; collagenases, gelatinases and stromelysins) capable of degrading all the components of connective tissue matrices at physiological pH. We document the patterns of synthesis and distribution of MMPs and the tissue inhibitor of metalloproteinases-1 (TIMP-1) within the developing rabbit mandibular condyle using immunofluorescence microscopy. MMPs and TIMP-1 were detected both as bright intracellular accumulations within Golgi vesicles and also as diffuse matrix-bound extracellular deposits. Cells in the articular zone, proliferative zone, condylar cartilage and bone of the mandibular ramus were shown to produce all 3 classes of MMPs and TIMP-1 with the exception of stromelysin, which was not synthesised by cells of the bone of spongiosum. Temporal synthesis of MMPs and TIMP-1 within these regions varied during the period 18 d postcoitum to 14 d postnatum. Our results document unique patterns of MMP and TIMP-1 synthesis during embryonic and early postnatal development of condylar cartilage and support the concept that cells synthesise and secrete MMPs and TIMP-1 before undergoing proliferation and hypertrophy. A comparison of these results with data in the rabbit growth plate show many similarities, but some differences exist that probably reflect differences in the modes of growth of the 2 cartilages.
Asunto(s)
Matriz Extracelular/metabolismo , Cóndilo Mandibular/crecimiento & desarrollo , Metaloendopeptidasas/biosíntesis , Animales , Colagenasas/análisis , Gelatinasas/análisis , Glicoproteínas/análisis , Glicoproteínas/biosíntesis , Inmunohistoquímica , Cóndilo Mandibular/embriología , Metaloproteinasa 3 de la Matriz , Inhibidores de la Metaloproteinasa de la Matriz , Metaloendopeptidasas/análisis , Microscopía Fluorescente , Conejos , Inhibidores Tisulares de MetaloproteinasasAsunto(s)
Diente Premolar/anomalías , Diente Supernumerario , Niño , Humanos , Masculino , Mandíbula , Diente Supernumerario/patologíaRESUMEN
Developmental defects of enamel were assessed in 15-year-old children born and continuously resident in three communities in the north east of England. In naturally fluoridated Hartlepool (F = 1.0-1.3 ppm), artificially fluoridated Newcastle (F = 1.0 ppm) and non-fluoridated Middlesbrough (F < 0.2 ppm) 361, 356 and 376 children respectively were examined. Conventional clinical recording and a photographic technique where colour slides are assessed at random were used and compared. Scoring in both assessments was done by using a modified version of both the Murray and Shaw index and the developmental defects of enamel index. In the clinical assessment more white lines and diffuse opacities were found in the fluoridated areas than in the non-fluoridated area. More opacities were recorded using the photographic assessment than with the clinical assessment, but a similar trend of an increased prevalence of white lines and diffuse opacities was observed using the photographic method. Overall, there was only a small increase in the prevalence of milder forms of enamel defects in fluoridated compared with non-fluoridated areas.
Asunto(s)
Fluoruración/efectos adversos , Fluorosis Dental/epidemiología , Adolescente , Distribución de Chi-Cuadrado , Inglaterra/epidemiología , Fluoruración/estadística & datos numéricos , Fluorosis Dental/etiología , Humanos , Incisivo , Variaciones Dependientes del Observador , Fotograbar , Prevalencia , Pastas de Dientes/farmacologíaRESUMEN
A case is presented in which two supernumerary teeth developed in the mandibular premolar region during orthodontic treatment. Their presence was only detected on a routine post-treatment radiograph. The potential hazards of space closure with such teeth present are considered, although there were no detrimental effects in the case illustrated.
Asunto(s)
Diente Premolar/anomalías , Diente Supernumerario , Diente Premolar/patología , Niño , Humanos , Masculino , Mandíbula , Diente Supernumerario/patología , Diente no Erupcionado/patologíaRESUMEN
Caries experience in 1374 children aged 15-16 years from three towns in the north east of England with varying concentrations of fluoride in drinking water, was determined. The mean DMFT values for 15-year-old continuous residents was 1.7 in Hartlepool (natural F 1.0-1.3 ppm), 2.5 in Newcastle (F adjusted to 1.0 ppm) and 3.3 in Middlesbrough (F = 0.2 ppm). Forty per cent of Hartlepool 15-year-olds were caries free, compared with 30% in Newcastle and 24% in Middlesbrough. Caries prevalence for both Hartlepool and Newcastle 'continuous residents' was lower than for non-continuous residents, whereas in Middlesbrough, the low fluoride area, non-continuous residents had a lower DMF value than those who had lived in Middlesbrough all their lives. There was a slight trend in both Newcastle and Middlesbrough for DMFT values to increase from social class I to social class V, but no discernable trend was observed in Hartlepool. The results for Hartlepool 15-year-olds were very similar to those reported by Weaver in 1949.
Asunto(s)
Caries Dental/epidemiología , Fluoruración , Adolescente , Análisis de Varianza , Índice CPO , Inglaterra/epidemiología , Humanos , Características de la Residencia , Clase SocialRESUMEN
Non-osteogenic fibroma is a lesion most commonly seen within the metaphyseal region of the tibia or femur presenting during the second decade. Few cases have been reported in the jaws and all occurred in the mandible. This report documents an 18-year-old female with a non-osteogenic fibroma in the condyle.