Biomedical subjects

M A Papadopoulos

Publications and source records attributed to M A Papadopoulos.

8 recordsLinked to original sources

PubMed2006

Accuracy and precision of the three-dimensional assessment of the facial surface using a 3-D laser scanner.

Three-dimensional (3-D) recording of the surface of the human body or anatomical areas has gained importance in many medical specialties. Thus, it is important to determine scanner precision and accuracy in defined medical applications and to establish standards for the recording procedure. Here we evaluated the precision and accuracy of 3-D assessment of the facial area with the Minolta Vivid 910 3D Laser Scanner. We also investigated the influence of factors related to the recording procedure and the processing of scanner data on final results. These factors include lighting, alignment of scanner and object, the examiner, and the software used to convert measurements into virtual images. To assess scanner accuracy, we compared scanner data to those obtained by manual measurements on a dummy. Less than 7% of all results with the scanner method were outside a range of error of 2 mm when compared to corresponding reference measurements. Accuracy, thus, proved to be good enough to satisfy requirements for numerous clinical applications. Moreover, the experiments completed with the dummy yielded valuable information for optimizing recording parameters for best results. Thus, under defined conditions, precision and accuracy of surface models of the human face recorded with the Minolta Vivid 910 3D Scanner presumably can also be enhanced. Future studies will involve verification of our findings using test persons. The current findings indicate that the Minolta Vivid 910 3D Scanner might be used with benefit in medicine when recording the 3-D surface structures of the face.

Algorithms↗

PubMed2005

Foetal surgery and cleft lip and palate: current status and new perspectives.

Now-a-days, high-resolution ultrasound allows an accurate and relatively early diagnosis of congenital malformations. In a limited number of such conditions foetal surgery may be lifesaving. However, premature labour has been the major drawback for open foetal surgery. Recently, improvement of video-endoscopic technology has boosted the development of operative techniques for feto-endoscopic surgery, which has been demonstrated to be less invasive than the open approach. Main clinical application of fetoscopic procedures today is the treatment of feto-foetal transfusion syndrome. Although still in development, feto-endoscopic surgery seems to offer new hope for surgical foetal therapy not only in cases of life threatening conditions. Experimental intrauterine correction of cleft lip and palate (CLP) has been lately performed using the feto-endoscopic approach. This procedure offers two major advantages: first, scarless foetal wound healing and bone healing without callus formation, which would also allow a better/normal maxillary growth, and second, significant decrease of foetal and maternal morbidity. Herein, we report the current status of experimental and clinical foetal surgery and propose possible directions for continuing research to make intrauterine procedures safer. Furthermore, we discuss current knowledge and new perspectives of experimental foetal cleft lip and palate repair, which in the future may lead to such excellent results in the operative treatment of clefts, that less or no secondary corrections and therapies, such as orthodontic, dental, logopedic, etc. would be needed. Only if these conditions can be fulfilled, will we be able to improve substantially our therapy for the human foetus with a cleft lip and palate. In spite of all efforts, however, it must be considered that it may not ever be possible to find the optimal treatment method for this or other craniofacial malformations.

Animals↗

PubMed2003

Meta-analysis in evidence-based orthodontics.

OBJECTIVE: In the last 10 years, health sciences literature has seen a significant increase in papers that report findings of meta-analyses. Meta-analysis overcomes the weakness of conventional narrative literature review. Moreover, it has established itself as a significant tool in clinical research and evidence-based medicine. But despite its station in the field, it is not without controversy. The aim of this paper is to present the main controversies that surround meta-analyses and to discuss the most important issues of conduct and reporting of results derived from these studies. RESULTS: Controversial issues include the ability of the investigators to combine studies that differ in important aspects; such as study populations, experimental designs and quality controls, and the like. It has been argued that selection bias could exist. Thus, it is common for the results of metaanalyses to be contradictory. As any other statistical procedure or analytical approach, meta-analyses too can be misused or abused. Misleading results could be avoided if certain basic principles are followed in the conduct of a meta-analysis. In particular, attention should be given to: (a) the methods of literature search for the studies to be included in the analysis, (b) the measures taken to reduce or eliminate bias, (c) the inclusion and exclusion criteria of the individual studies from the analysis, (d) how the data will be extracted from the literature, and (e) how the data will be analyzed statistically. CONCLUSION: Reports of meta-analytical studies carried out with the above parameters in mind yield a more objective appraisal of the evidence, and a more precise estimate of the treatment effect.

Dental Research↗

PubMed2002

[Experimental endoscopic intrauterine surgery for craniofacial malformations such as the cleft lip and palate].

INDICATION FOR FETAL SURGERY: The widespread use of high-resolution ultrasound in prenatal diagnosis allows nowadays an accurate and early diagnosis of congenital malformations. Some of these can be corrected surgically. In certain cases intrauterine surgery could present functional and aesthetic advantages or be even lifesaving. Due to the extreme sensitiveness of the fetal patient and the fetal membranes, only some defined anomalies currently meet the criteria for intrauterine surgery. However, the list can change in the future since prenatal diagnosis, technical advances, and knowledge of pathophysiology improve constantly. ENDOSCOPIC INTRAUTERINE SURGERY: Additionally, the recent development of endoscopic intrauterine surgery represents a new and more careful possibility for intrauterine surgery. Endoscopic procedures could avoid the disadvantages of open intrauterine surgery and thus make fetal operations safer, in life-threatening as well as in non-life-threatening malformations such as cleft lip and palate (CLP). The main advantages of these procedures are (1) scarless wound healing and bone healing without callus formation that leave to expect normal growth of the midface and (2) lower fetal and maternal morbidity. DISCUSSION: Based on the results achieved until now, it can be stated that at present the intrauterine operation of CLP on humans cannot be recommended. The high morbidity and mortality risk for mother and fetus cannot be counterbalanced by the unsatisfactory results of a prenatal operation. CONCLUSION: In this study first results of an experimental investigation with the new endoscopic techniques are presented, whereby the possibilities for optimization and quality improvement of the intrauterine surgical procedures are analyzed in detail.

Animals↗

PubMed2001

Dentoskeletal morphology in children with juvenile idiopathic arthritis compared with healthy children.

The aim of this study was to evaluate the dentoskeletal relationships in children with juvenile idiopathic arthritis (JIA) compared to healthy children without significant differences in relation to age and sex, by means of lateral cephalometric radiographs. Cephalometric, as well as dental panoramic radiographs were taken of 66 JIA children (27 males and 39 females; age range: 6-19 years; mean age: 11.9 years). The control group consisted of 37 healthy children unaffected by JIA seeking orthodontic treatment, with Class I occlusion (17 males and 20 females; age range: 7.5-17 years; mean age: 11.9 years). All cephalometric landmarks were identified and digitized, and calculations were performed by means of a computerized cephalometric system. The cephalometric findings indicated a tendency towards retrognathism with a short mandible. The lower facial height was increased and the growth pattern of the face was biased towards the vertical direction (clockwise, i.e. with a tendency to open bite) and the interincisal angle was less in the JIA children compared to the healthy children. These findings were in general more pronounced by the JIA children with polyarticular type of the disease as well as with affected condyles. Our study indicated that the dentoskeletal morphology in children with JIA presented some special characteristics when compared to healthy children, which could be attributed to the effects of the disease.

Adolescent↗

PubMed1997

Clinical characteristics and properties of ceramic brackets: A comprehensive review.

The aim of this article is to provide the clinician with an up-to-date comprehensive literature review concerning the clinical characteristics and properties of ceramic brackets. The article critically presents and discusses the various aspects of ceramic brackets with regard to the types, physical properties, bond strength, frictional resistance, base surface characteristics, debonding techniques and enamel fracture risks, enamel abrasion and wear, bracket fracture, and bracket recycling. The article contains also guidelines and criteria concerning the specific applications and use of ceramic brackets.

Ceramics↗

PubMed1994

Cephalometric evaluation of pharynx, soft palate, adenoid tissue, tongue, and hyoid bone following the use of a mandibular repositioning appliance in obstructive sleep apnea patients.

The aim of this study was to evaluate the pharynx, soft palate, adenoid tissue, tongue, and hyoid bone when a mandibular repositioning appliance was used for managing patients with obstructive sleep apnea. Lateral cephalograms of 45 adult obstructive sleep apnea patients from the Lancaster Cleft Palate Clinic were taken without the appliance and some days later with the device in the mouth. This device was used during sleep for improving patients' respiration. Twenty-four cephalometric variables were evaluated. When the appliance was in the mouth, significant alterations (P < .001) were observed in the distances: (a) between anterior and posterior pharyngeal walls at the level of the second and third cervical vertebrae, respectively; (b) between the most superior point of the tongue and the maxillary plane; and (c) between the hyoid bone and the mandibular plane, ramus plane, cervical vertebrae tangent, mandibular symphysis, gonion, and third and fourth cervical vertebrae. The results of this study indicate that significant changes in pharyngeal space, hyoid bone, and tongue positions take place in obstructive sleep apnea patients when a mandibular repositioning device is used.

Adenoids↗

PubMedDate not supplied

[Results of a comparative study of skeletal anomaly Class II cases after activator, headgear and combined headgear-activator treatment].

The causal therapy of skeletal Class II anomaly consists of the changes of the jaws' relationships to each other during the growth of the craniofacial complex. A plenty of orthodontic appliances are employed, the effectiveness of which remain debatable. This paper attempts to compare the three main orthodontic appliances used in our clinic: activator, headgear and combined headgear activator. Patients with a skeletal Class II anomaly at the beginning of treatment were studied with two different types of cephalometric analysis. The lateral X-ray head films were carried out directly before and after treatment. In this study the growth pattern of the patients' craniofacial complex has been seriously taken into consideration. Following conclusions are to be taken: The initial skeletal Class II anomaly as well as the orthodontic appliances have to be differentially evaluated by the treatment planning. The isolated changes are often not great, but taken as a whole, they attain to correct the existing anomaly. The annual rates of the jaws' length depends not only on the age, the sex and the duration of orthodontic treatment, but also on the growth pattern of the craniofacial complex and the particularities of treatment methods. In order to achieve the therapeutic aims all these factors are to be considered for the treatment planning.

Activator Appliances↗