1,720,989 research outputs found
Three-dimensional ridge augmentation with xenograft and recombinant human platelet-derived growth factor-BB in humans: report of two cases
No full textThe present paper reports on two patients who underwent three-dimensional ridge augmentation using a xenograft in combination with recombinant human platelet-derived growth factor-BB (rhPDGF-BB). Patient 1 received a deproteinized bovine block infused with PDGF and secured to the alveolar crest by two fixation screws to augment the crest horizontally. After 5 months, implants were successfully placed. Patient 2 underwent a vertical ridge augmentation procedure that combined deproteinized bovine bone particles embedded in a collagen matrix soaked in PDGF Three titanium dental implants were placed in each patient 5 months later. Clinical and histologic results showed excellent soft and hard tissue healing. Bone had regenerated throughout the whole area and the xenograft particles were embedded in bone, which presented resorption lacunae close to areas with ongoing bone formation. This indicated that, in augmented areas, intense physiologic remodeling was ongoing. No data exist concerning three-dimensional bone augmentation using PDGF and a xenograft in humans. This report suggests that the use of rhPDGF-BB in combination with a deproteinized bovine graft may have the potential to regenerate large three-dimensional alveolar defects in humans
Occlusal morphology one year after orthodontic and surgical-orthodontic therapy : a quantitative analysis of clinically successful patients
No full textOBJECTIVE: To evaluate morphologic characteristics of occlusion (contact points, contact areas, and frequency of contact) in clinically successful patients 1 year after orthodontic and surgical-orthodontic therapy followed by passive retention. MATERIALS AND METHODS: Twenty-two orthodontic and 18 surgical-orthodontic patients were analyzed. All patients were treated with standard edgewise technique by the same orthodontist. Contact points and areas were evaluated using a new method of digital image analysis of occlusal impressions. Polivinylsyloxan impressions were taken, scanned, and turned into gray-scale images. The physic relationship of light absorbance through the polivinylsyloxan for known thickness was calculated to determine contact areas (less than 50 microm of thickness) and near contact areas (less than 350 microm of thickness). RESULTS: The contact area was significantly larger in the orthodontic than in the surgical-orthodontic patients (Student's t-test, P < .05). The surgical-orthodontic group had significantly fewer contact points than the orthodontic group only at 150 microm of thickness. In both groups of patients, the first molar had the largest contact surface. Occlusal support was distributed mainly in the posterior regions with an important role involving the first molars. CONCLUSION: Surgical-orthodontic patients appear to have smaller contact surfaces and fewer contact points than orthodontic patients do. However, there were no differences in the number of teeth in contact with opposing teeth
Three-dimensional analysis of hard palate in Down syndrome subjects
No full textAim: Down syndrome (DS) is the most frequent chromosomal aberration in man, with a prevalence of about 40,000 affected people in Italy, resulting from complete or partial trisomy of chromosome 21. Several peculiar maxillofacial features have been described in DS subjects, but quantitative assessments of hard tissue palatal features in subjects are still scanty (1) and no data concerning Italian DS people do exist. The purpose of the study was to collect data on palatal size and shape in DS subjects focusing on the major determinants of the hard palate modifications, whether only the Down syndrome or some other variables. Both the dental formula and the ethnicity were thus considered.
Materials and Methods: Hard tissue palatal shape and dimensions in 41 Italian DS subjects (29 men, 12 women) were analyzed and compared to normal reference data (15 men, 13 women). Palatal landmarks were digitized with a 3D computerised electromagnetic instrument and their coordinates were used to construct a mathematical equation of palatal shape, independent of dimensions (2, 3). Palatal length, slope, width, maximum palatal height in both sagittal and frontal plane were measured and two percentage ratios (maximum height to width and width to length) were obtained.
Results: All average dimensions were reduced in DS subjects without any significant sex difference except for palatal height in the sagittal plane (larger in males). The height to width ratio increased in Down syndrome individuals, while width to length ratio was similar. In the sagittal plane the curves of DS and normal subjects within each sex were nearly superimposable; in the frontal plane Down individuals showed a higher palate than healthy subjects, particularly females. To assess the influence of posterior teeth on palatal morphology, DS males were then divided in two groups (eight totally edentulous and 21 partially dentate) and compared to normal subjects by analysis of variance. Global F values were significant for all variables. Partial comparisons showed significant smaller measures in edentulous versus dentate DS males (not width) and versus normal subjects (not slope). All parameters but slope and height in the frontal plane were larger in reference than in partially dentate DS males. Shape modifications were larger in edentulous subjects with a flattening of palatal curves; all ratios were significantly reduced.
Conclusions: Trisomy of chromosome 21 seems to alter the normal palatal size and shape in Italian subjects, although further analyses may involve a larger group. Quantitative data on palatal features could be useful for clinicians when planning dental rehabilitation of DS patients, providing a reference to construct suitable prosthetic devices with improved oral health and dental care
Palatal size and shape in 6-year olds affected by hypohidrotic ectodermal dysplasia
Full text linkObjective: To analyze the size and shape of the hard tissue palate of Italian subjects with hypohidrotic ectodermal dysplasia (HED). Materials and Methods: The morphology and the dimensions of the hard tissue palate were analyzed in eight 6-year-old boys affected by HED. Four of the boys were completely edentulous and four partially dentate. Palatal landmarks were identified on stone casts and digitized with three-dimensional computerized electromagnetic instrumentation. Palatal length, slope, width, and maximum palatal height in both the sagittal and frontal planes were measured. From the coordinates of palatal landmarks, a mathematical equation of palatal shape was constructed, independent of size. HED palatal data were compared with reference data obtained from 12 healthy boys with a complete deciduous dentition. Results: Palatal length and height in both the sagittal and frontal planes were significantly reduced in HED as compared with control individuals. A less steep (not significant) palatal slope was found in HED than in reference subjects, whereas similar palatal width values were observed. All palatal measurements were larger in partially dentate than in edentulous patients. Both HED and edentulousness influenced palatal shape. The HED boys had a relatively lower palate than the reference boys. In the edentulous HED boys, the hard tissue palate was relatively lower than in partially dentate HED subjects. Conclusions: Palatal size and shape were significantly modified by the presence of hypohidrotic ectodermal dysplasia, and the major alterations were found in edentulous HED subjects
Bone regenerated via rhPDGF-bB and a deproteinized bovine bone matrix : backscattered electron microscopic element analysis
No full textThis study used backscattered electron microscopy (BSE-SEM) to analyze specimens in which bone was augmented both horizontally and vertically with a xenograft scaffold and recombinant human platelet-derived growth factor (rhPDGF-BB), with or without a resorbable collagen membrane. The study objective was to compare percentage weight and volume calcium-phosphorus ratios of regenerated bone and native bone and the nature of the bony contact with two different implant surfaces. Examination of the nature of the mineralized tissues by BSE-SEM provides an understanding of the composition and element ratio of bone regenerated from nonautogenous grafts. The data collected demonstrated no statistically significant difference between regenerated bone and native bone in the two tested groups. Our observations suggest that bone regenerated via nonautogenous grafts displays composition, structure, and physical properties very similar to those of native bone. Similarly, no significant differences were observed at the bone-implant interface between bone regenerated proximal to oxidized versus machined implants
Correlazione tra immagini radiografiche e anatomia dei canali radicolari dei primi molari inferiori
No full textIntroduction- Nowadays, the anatomy of endodontic system, particularly of the apical third, has reached a primary interest in planning the cleaning, shaping and filling of root canals.
Aim of the study- The present study aimed to correlate the actual anatomy with the radiologic anatomy of the canals of the first human mandibular molars.
Method- Six mandibular first molars were extracted in periodontal patients and embedded in acrilic resin. Canal diameters were measured by means of intraoral radiographies and photographic images of serial sections. Data were compared with one-way analysis of variance (ANOVA, p<0.05).
Results- Statistically significant differences between radiographic and photographic measures were found in all root canals (ANOVA, p<0.05). A continuous funnel taper was not evident in mesio-vestibular and mesio-lingual canals in none of the four analyzed radiographic projections. In contrast, distal canal revealed a cilindric shape in 90° radiographic projection and a continuous funnel taper in 0° projection.
Conclusions- The differences between the observed data of the canal diameters in the first mandibular molars showed a lower appraisal (about 25-30%) of the actual canal anatomy in radiographic images
Histologic analysis of human alveolar bone regenerated with xenograft and rh-platelet-derived growth factor-BB
No full textAs previously showed for the classical self renewing tissues (i.e. bone marrow, gut and skin), rapidly changing concepts about tissue stem cell biology identify the liver as a maturational lineage system capable to generate mature cells (hepatocytes and cholangiocytes) from a resident stem cells compartment localized near the so called Canals of Hering. At present liver transplantation is the only available therapy for end stage liver diseases and there is an ever increasing shortage of donor livers. Thus in the last decades, HPC has becoming the object of many researchers since HPC might offer a new therapeutic approach for controlling the evolution of chronic liver diseases. The aim of the present review is to update readers with the evolving concepts about hepatic stem cells biology, their characterization and isolation methods and finally their therapeutic potential
Soft tissue facial angles in Down's syndrome subjects : a three-dimensional non-invasive study
No full textThe aim of the present study was to obtain quantitative information concerning the three-dimensional (3D) arrangement of the facial soft tissues of subjects with Down's syndrome. The 3D co-ordinates of 50 soft tissue facial landmarks were recorded by an electromechanical digitizer in 17 male and 11 female subjects with Down's syndrome aged 12-45 years, and in 429 healthy individuals of the same age, ethnicity and gender. From the landmark co-ordinates, geometric calculations were obtained of several 3D facial angles: facial convexity in the horizontal plane (upper facial convexity, mid facial convexity including the nose, and lower facial convexity), mandibular corpus convexity in the horizontal plane, facial convexity including the nose, facial convexity excluding the nose, interlabial angle, nasolabial angle, angle of nasal convexity, left and right soft tissue gonial angles. Data were compared with that collected for the normal subjects by computing the z-scores.Facial convexity in the horizontal plane (both in the upper and mid facial third), facial convexity in the sagittal plane and the angle of nasal convexity were significantly (P < 0.05) increased (flatter) in subjects with Down's syndrome than in the normal controls. Both left and right soft tissue gonial angles were significantly reduced (more acute) in the Down's syndrome subjects. Subjects with Down's syndrome had a more hypoplastic facial middle third with reduced nasal protrusion, and a reduced lower facial third (mandible) than reference, normal subjects
Oral features in five adult patients with Wolf-Hirschhorn syndrome
No full textThe Wolf-Hirschhorn syndrome (WHS) is a rare genetic condition presenting with severe mental disability, growth retardation, muscular hypotonia, seizures, craniofacial abnormalities and defects in the cardiovascular, genitourinary and digestive apparata. To date, few data about oral status of afflicted patients were reported, and this syndrome is still unfamiliar among dental and maxillofacial professionals. Aim of the present case series was to provide oral data from five patients with WHS (3 women and 2 men) aged 19-41 years. All patients entered in a long-stay Institution with an inner dental service in 1998 and underwent regular dental examination and hygiene treatment. Neither tooth agenesis or dental size and shape anomalies were found in the analyzed subjects except for one man showing multiple cone-shaped teeth. At the beginning, bad dental and periodontal conditions with gingival signs and recurrent mucosal inflammation were found in all patients. After motivation of their tutors, dental and periodontal parameters were recorded during periodic assessments and a large decrease in the gingival index was found over time. These data could aware dentists about the therapeutic modalities to improve oral health of WHS patients
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