PubMed Health⌕ Search

Biomedical subjects

N Toutountzakis

Publications and source records attributed to N Toutountzakis.

At least 19 recordsLinked to original sources
PubMed1992

Skeletal stability after surgical correction of mandibular prognathism by vertical ramus osteotomy.

The purpose of the study was to assess skeletal stability following combined surgical-orthodontic management of 52 adults with severe mandibular prognathism. Lateral cephalograms taken 1 week before surgery, within 1 week post-surgery and approximately 1 year after operation were studied by means of eight variables and a constructive stable reproducible reference system. The surgical procedure of choice was a bilateral vertical ramus osteotomy through an extra-oral approach. In all cases the condyles were left passively in the articular fossa and no attempt at their active repositioning was made. The patients were randomly allocated to an osteosynthesis or non-osteosynthesis group with regard to intramandibular fixation. Intermaxillary fixation lasted 6 weeks and an interocclusal wafer was used in all cases during this period. The findings of this study showed that during the post-operative period there was a trend for posterior rotation of the mandibular corpus (P less than 0.001). This pattern was also characterized by an increase (P less than 0.001) of the lower anterior face height and an improvement of the angle of convexity (P less than 0.001). These changes occurring in a direction so that the dentoskeletal profile became less concave, did not tend to reverse the goal of operation and cannot be considered as detrimental. No significant differences (P greater than 0.05) were found between the groups without and with osteosynthesis.

Adolescent↗
PubMed1991

Alterations of hyoid bone position and pharyngeal depth and their relationship after surgical correction of mandibular prognathism.

The present investigation studied changes of hyoid bone position and pharyngeal depth at the levels of the second and fourth cervical vertebrae and their relationships in mandibular prognathism patients who received combined orthodontic-surgical treatment. The material consisted of presurgical and 1-year postsurgical profile cephalograms of 52 adult orthognathic surgery patients (40 females and 12 males) who initially had mandibular prognathism and had undergone bilateral vertical ramus osteotomy through an extraoral incision in the retroangular area. Hyoid bone position and pharyngeal depth were assessed on the profile radiographs with 10 cephalometric variables. Paired t tests were used to evaluate the operative changes in all cephalometric parameters. The relationships between pairs of variables describing hyoid bone position and pharyngeal depth were assessed by means of Pearson's product-moment correlation analysis. Significant differences (p less than 0.01) were observed for the distances of the hyoid bone to the maxilla and the mandible. The distances of the hyoid bone with the anterior cranial base, the vertebral column, and the anterior pharyngeal wall, and the measurements representing pharyngeal depth exhibited no significant changes (p greater than 0.05). Moderate correlations were seen between (1) the depth of the pharynx at the fourth cervical vertebra and the hyosymphyseal distance (r = 0.34) and the distance between the point of the projection of the hyoid bone to the mandibular line with its posterior border (r = -0.34), and (2) the depth of the pharynx at the second cervical vertebra and the distance of the hyoid bone with the anterior pharyngeal wall at the level of the fourth cervical vertebra (r = -0.33).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Frontal cephalometric evaluation of transverse dentofacial morphology and growth of children with isolated cleft palate.

The transverse dentofacial morphology and growth of 64 children operated on for clefting of the hard and soft palate was studied by means of a frontal proportional cephalometric analysis and was compared to a normal sample at the ages 3-4, 8-9 and 12 years. The cross-sectional comparison of the cleft palate and normal samples at the three periods indicated: (a) The presence in the cleft group of significantly increased ratios of the inner orbital width to the interorbital width and of the width of the nasal cavity to the interorbital width; (b) the absence of any significant differences in the ratio of the maxillary intermolar width to the interorbital width; and (c) the presence of almost identical ratios of the intergonial width of the mandible to the interorbital width and of the width of the maxilla to the intergonial width of the mandible. Evaluation of the changes of all cephalometric variables during the period 8-12 years showed the absence of any significant difference between the cleft palate and normal groups.

Age Factors↗
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↗
PubMed1990

[Ectopic eruption of the maxillary first permanent molar].

Ectopic eruption of the first maxillary molars shows a prevalence of 2 to 6% and is classified in two different types: I) "Jumping type" or "reversible ectopic eruption" II) "holding type" or "irreversible ectopic eruption". Different local as well as hereditary factors have been considered as responsible for the ectopic eruption. "Right on time" diagnosis and treatment subsequently, make the latter efficient and mainly easier for both the patient and the treating dentist.

Child↗
PubMed1990

[Soft tissue and dentoskeletal profile changes associated with mandibular advancement osteotomy].

The aims of the present cephalometric study were to describe the profile interrelationships between soft and dentoskeletal tissues following mandibular advancement osteotomies, and to detect, if there were any cephalometric variables, that could contribute to an accurate prediction of the surgical effect on the profile. The presurgical and postsurgical lateral cephalograms of 14 consecutive patients (ten females and four males) who received combined orthodontic-surgical management of their mandibular retrognathism by means of a bilateral sagittal split osteotomy, and whose age at the time of surgery ranged from 16 to 41 years, were used. Lateral cephalograms with the teeth in centric occlusion taken before operation and one year after surgery were available for all patients. A computerized cephalometric appraisal was used, including variables corresponding to the sagittal and vertical relationships of skeletal and soft tissue profile, incisal relationships, soft tissue thickness and lip morphology. The statistical elaboration of the data was made by means of paired t-test, Pearson's product-moment coefficient of correlation and multiple regression analyses. Assessment of the results revealed that considerable facial changes and improvement took place following both operations. The skeletal and soft tissue facial profile was straightened and the posture of the lower lip was improved. Anterior movement at points B and Po was accompanied by changes at the corresponding soft tissue landmarks ranging from 59 to 122 percent. The changes of soft tissue pogonion, inferior labial sulcus and labrale inferius were found to correspond with 104, 122 and 75 percent of the movement of the skeletal landmark pogonion, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Diagnosis of the maxillary dentoskeletal discrepancies in the transverse plane of space].

The dentoskeletal discrepancies of the craniofacial complex in the transverse dimension which usually appear in combination with similar discrepancies in the antero-posterior and the vertical dimension or more ravely by themselves, are of the highest interest for the clinical orthodontist and increase the complexity of the diagnostic procedure in these cases. In this study emphasis in given in diagnostic evaluation of the cases with transverse maxillary discrepancies. Diagnostic criteria which must be taken under consideration both during clinical examination and during orthodontic model study are described and the most important cephalometric methods which can help the diagnosis in these cases are referred.

Adolescent↗
PubMed1989

[Segmented arch technique and incisor intrusion for deep overbite correction].

The mechanisms which will be selected for the correction of deep overbite depend exclusively on the choice of the clinician for: 1. Gennine anterior teeth intrusion. 2. Eruption of posterior teeth. 3. Combination of anterior intrusion and posterior extrusion. Principles of incisor intrusion have been presented as well as the use of intrusive springs in the segmented arch technique. Six principles must be considered in incisor intrusion: 1) the use of forces of optimal magnitude and constancy, 2) the use of a single point contact in the anterior region, 3) selection of the point of force application with respect to the center of resistance of the anterior segment, 4) selective intrusion based on anterior tooth geometry, 5) control over the reactive units and 6) inhibition of eruption of the posterior teeth and avoidance of undesirable eruptive mechanics.

Humans↗
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

[Soft tissue profile changes following mandibular rami osteotomies].

Rami osteotomies used to correct mandibular prognathism and retrognathism is a well known fact that produce also changes at the shape and position of the soft tissues. These changes in the relationship of hard tissue to soft tissue are reported as well as predicting formulas. All these information can be used as a guide in planning orthognathic surgery once their limitations is well understood.

Cephalometry↗
PubMed1989

[Relationship between upper dental arch width and other dimensions of the head and face].

The relationship between upper dental arch width and some dimensions of the face and head in children 10-12 years of age (177 children with normal occlusion, 59 with Class II div. 1, 35 with Class II div. 2 and 27 with Class III) was examined in this study. Although different dimensions of the face and head and the upper dental arch width were found to be significantly correlated in children with normal occlusion, this relationship is not found to be strong enough in children with different categories of malocclusion. No significant diagnostic elements were found having general application during treatment planning.

Cephalometry↗
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↗
PubMed1989

[Combination of orthodontic and endodontic treatment].

Many scientists and researchers have up to now been interested in the subject of the combination of orthodontic and endodontic treatment. The uncertainty of the orthodontic movement upon endodontically treated teeth tends to disappear after the conclusions of long lasting studies proving that the biological tissue reactions that happen during orthodontic movement of endodontically treated teeth are identical with those of healthy teeth which are under orthodontic treatment. In this study we were referred to the accessible bibliography on biological tissue reaction upon the combination of orthodontic and endodontic treatment and we have presented some our cases which are treated by combination of orthodontic and endodontic treatment.

Adolescent↗
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↗