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Biomedical subjects

M Lagoudakis

Publications and source records attributed to M Lagoudakis.

13 recordsLinked to original sources
PubMed1997

Combined intrusion and retraction generated by cantilevers with helical coils.

Combined retraction and intrusion of the anterior teeth is often needed as part of orthodontic treatment. The use of a statically determinate force system has many advantages over statically indeterminate systems. In the case of the cantilevers the orthodontist can evaluate the line of action of the delivered force directly in the clinical situation. In the present paper the force system delivered by stainless steel and beta titanium cantilevers with an eccentrically placed helix was evaluated. The cantilever consisted of a straight piece of wire bent to form a helix with an external diameter of 3 mm. The wire was fixed into a bracket of sensor 1, touching sensor 2 of a test bench with a 1-point contact to. Activation was induced by rotating sensor 1 into which the wire was tightly fixed. This was done in 2 different modes, one in the direction in which the helix was bent and one in the opposite direction. With an interval of 5 degrees the force system generated with respect to sensor 1 and the direction of the force delivered to sensor 2 (the other bracket) were registered. The results were expressed graphically and the influence of material and activation mode were evaluated statistically by comparing the coefficient of regression. As expected, the influence of the material reflected the relative stiffness of the 2 alloys. As TMA is monocrystalline (i.e. consists of homogeneous crystals) the mode of activation did not reflect any significant Bauschinger effect as seen in the case of stainless steel. Analysis of the force direction confirmed that the suggested wire configuration is useful for delivery of a predetermined combination of horizontal and vertical force. This was confirmed by a finite element analysis.

Dental Alloys↗
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↗
PubMed1990

[Techniques of surgical exposure of unerupted maxillary anterior teeth for orthodontic management].

The problem of impaction of the maxillary anterior teeth can be solved under cooperation of the oral and maxillofacial surgeon and the orthodontist. In that way unerupted teeth which in the past were scheduled to be extracted, nowadays can be saved and take their place in the dental arch. There are various surgical techniques of exposure of unerupted anterior maxillary teeth, for orthodontic management. Decision of the most suitable for each individual case can be taken after careful analysis of the diagnostic data from the surgeon and the orthodontist taking under consideration the location of the unerupted tooth, the periodontal status and the patients' cooperation. In this paper reference is being made in different techniques of surgical exposure for orthodontic traction with regard to the maintaining of a good tooth-gingiva relationship. Same clinical cases are also presented.

Cuspid↗
PubMed1990

[A study of mechanical properties of orthodontic wires in tension].

Orthodontic forces are applied to the teeth basically by means of different types of orthodontic wires. Knowledge of the mechanical properties of such wires are very helpful to the clinician in design and application of optimal force systems during orthodontic treatment. The basic mechanical properties were studied for 17 types of orthodontic wires (all rectangular and of the same size), in tension. Modulus of elasticity (E), yield strength (YS) and maximum elastic strain (Springback) (YS/E) were calculated for each type of wires. Stainless steel wires have demonstrated higher modulus of elasticity (and yield strength) in comparison with wires of nickel-titanium and beta titanium alloys. B-titanium wires showed higher modulus of elasticity than nickel-titanium ones. In addition stainless steel wires were found to have higher values for springback than cobalt-chromium ones and lower values (for the same variable) than nickel-titanium and B-titanium wires.

Dental Alloys↗
PubMed1989

[A study of esthetic harmony and balance of the facial soft tissue].

Esthetics and harmony of the human body have been for ages sources of research and inspiration for scientists and artists. The face affects the appearance and determines, in a way, the limits in the evaluation of beauty influenced by various psychological, environmental or other factors. There are some studies dealing with facial proportions in which researchers are trying to establish some mathematic norms for the evaluation of the "esthetic face". In this paper, a study of some facial proportions is carried out, in photographs of female faces with three different expressions, seriousness, relaxed position and smile. Our findings show that smiling faces are significantly different from serious and relaxed faces in most of the proportions studied. The "Golden proportion" was closer to the proportions of the serious and relaxed faces than to the proportions of the smiling ones.

Cephalometry↗
PubMed1989

[Dimensions of the palate and dental arches in Greek adults with open bite].

In this study, the relationship of some dimensions of the palate and the dental arches, of 30 adults with open bite and 53 adults with normal occlusion was examined. Statistical analysis showed that in both sexes were found statistically significant differences exactly in the same measurements between the two groups. Statistically significant relationship was found between some dimensions of the dental arches in the group of adults with normal occlusion. This relationship was not found in the open bite group.

Adult↗
PubMed1989

[Treatment of impacted upper central incisor].

The impaction of the upper central incisor is a common problem for the clinical orthodontist. The correct diagnosis is a fundamental factor in trying of the alignment of this tooth in the dental arch. There are cases where treatment should be conservative and removing the responsible for the impaction factor is all need to be done, for the tooth to erupt. In other cases, however, surgical exposure and orthodontic traction are both necessary. Three cases with impaction of the upper central incisor are described as well as the treatment provided and a literature review of the above subject is presented.

Child↗
PubMedDate not supplied

[Surgical exposure with an apically repositioned flap and orthodontic management of an upper impacted canine].

The combination of surgical exposure and orthodontic traction is usually the treatment of choice in cases with unerupted upper anterior teeth. Different methods of surgical exposure have been described with specific indications for each one. In this paper we present a case with an unerupted upper right canine and describe its management, after surgical exposure with an apically repositioned flap and orthodontic traction. Contemporary aspects of this technique are referred with regard to its advantage of maintaining a good tooth-gingiva relationship.

Child↗