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Biomedical subjects

C Katsaros

Publications and source records attributed to C Katsaros.

At least 19 recordsLinked to original sources
PubMed2006

Steiner cephalometric analysis: predicted and actual treatment outcome compared.

OBJECTIVE: To examine the accuracy and precision of the Steiner prediction cephalometric analysis. SETTING AND SUBJECTS: The sample consisted of 275 randomly selected patients, treated between 1970 and 1995 at a university department. METHODS: Lateral cephalograms before (T1) and after orthodontic treatment (T2) were analyzed using the Steiner analysis. A prediction of the final outcome at T2 for the variables ANB degrees, U1 to NA mm, L1 to NB mm, and Pg to NB mm was performed at T1. The difference between the actual outcome at T2 and the Steiner predicted value (SPV), which was done at T1, was calculated. Accuracy (mean difference between T2 and SPV) and precision (standard deviation of the mean prediction discrepancies) of the prediction were studied. Paired t-test was used to detect under- or overestimation of the predicted values. RESULTS: The mean decrease in angle ANB was 1.4 +/- 2.7 degrees and for U1 to NA 2.0 +/- 2.6 mm, while L1 to NB increased 0.8 +/- 2.0 mm and Pg to NB 0.7 +/- 1.1 mm. The predicted values for the changes in ANB angle, the distance of upper incisor U1 to NA as well as the distance Pg to NB were significantly overestimated when compared with the actual outcome, while the change in the distance of lower incisor L1 to NB was underestimated. CONCLUSION: The prediction of cephalometric treatment outcome as used in the Steiner analysis is not accurate enough to base orthodontic treatment decisions upon.

Adolescent↗
PubMed2006

Microdontia after chemotherapy in a child treated for neuroblastoma.

OBJECTIVE: Chemotherapy used on paediatric oncology patients often causes disturbances in dental development. Aim of this case report is to present the late effects of chemotherapy on dental development in a patient treated for neuroblastoma at early age. DESIGN: Case report. RESULTS: This paper presents a female patient treated at early age with surgery and chemotherapy for a neuroblastoma (stage IVS) in the right thorax and massive liver metastases. The examination of the patient at age 11.7 years showed microdontia of six teeth. In three of them size and form of the crown were affected, while in the other three the size was reduced but the form was not affected. CONCLUSIONS: Chemotherapy on children treated for neuroblastoma can adversely influence tooth development. This has to be taken into consideration by the dentist when monitoring the development of the dentition and occlusion.

Antineoplastic Agents↗
PubMed2006

[Bone anchorage in orthodontics. A review].

The achievement of absolute anchorage in orthodontics overcoming the reaction forces and moments has been problematic for a long time. This was caused on the one hand by the limitations of the devices available and on the other hand by the dependence on patient cooperation. The introduction of bone anchorage systems changed the traditional way of thinking on orthodontic anchorage. Whereas the application of anchor systems, such as palatal implants and onplants, has specific indications, bone screws with or without plates seem to have the potential of being used on a routine basis. However, appropriate data for more complete understanding of the biological and biomechanical background of this concept of orthodontic anchorage are still lacking. Furthermore, studies on the effectiveness of these systems when compared to the traditional orthodontic anchorage and based on large groups of patients are not available. Well-designed prospective clinical trials substantiating the evidence-based use of these devices are needed.

Bone Screws↗
PubMed2006

[Kabuki syndrome, a congenital syndrome with multiple anomalies].

The characteristics of a 5-years old girl, referred to a multidisciplinary team for cleft lip and palate because of speaking problems, were diagnosed as Kabuki syndrome. The Kabuki syndrome is a congenital syndrome of unknown aetiology, diagnosed based on a combination of clinical findings. It is characterised by distinctive facial features, skeletal anomalies, dermatoglyphic abnormalities, developmental delay and mild to moderate mental retardation. Children with the syndrome often have oral manifestations such as cleft palate, missing permanent teeth and conic crowns of upper incisors. The Kabuki syndrome was first described regarding the Japanese population but it is now known to occur in many other races as well. In a recent publication, 20 Dutch patients with Kabuki syndrome were described.

Abnormalities, Multiple↗
PubMed2005

A unique pattern of F-actin organization supports cytokinesis in vacuolated cells of Macrocystis pyrifera (Phaeophyceae) gametophytes.

The organization of actin filaments and their role in cytokinesis was studied in regenerating protoplasts and thallus cells of gametophytes of the brown alga Macrocystis pyrifera. Before the onset of cytokinesis, a ring of actin filaments appeared on the putative cytokinetic plane just under the plasmalemma. Light and electron microscopy of cytokinetic cells revealed that large vacuoles occupy the space between the daughter nuclei, which very often are eccentrically positioned at the cell cortex. By the progress of cytokinesis, actin filament bundles emanating from the cytokinetic ring tend to form an actin plate that enters cytoplasmic pockets in which the cytokinetic diaphragm develops. The mechanism of this cytokinetic pattern that has not been reported so far for brown algae is discussed.

Actin Cytoskeleton↗
PubMed2004

[Digital cephalometrics].

There are different methods to produce digital head films and all have advantages and disadvantages. With a digital head film and a computer programme for digital cephalometry an analysis can be performed easily. All existing computer programmes for digital cephalometry use reference values to compare with the patient's values. However, the magnification factors of the two data sets, which are compared, must be known and correction to the same magnification must be possible within the programme. Furthermore, the reference values should be age, gender, and population related. Many commercially available programmes do not fulfil these criteria. A well-designed programme for digital cephalometry should have the possibility to calculate age and gender-related reference values based on values of the target population. Furthermore it should have the possibility to analyse several longitudinal head films at the same time and to present the data graphically. A national survey among Dutch orthodontists by the end of 2000 demonstrated that 35% of Dutch orthodontists used digital cephalometry in their office. The most commonly used analysis was the Steiner-Tweed analysis, which was performed by nearly 60% of the orthodontists.

Age Factors↗
PubMed2003

[Self-ligating edgewise brackets. An overview].

During the last years both the manufactures and the orthodontists seem to show an increased interest in self-ligating brackets. This paper aims to present the history of self-ligating systems, to describe the three mostly used bracketsystems and to review the relevant literature. It seems from the existing data that self-ligating brackets have certain advantages over conventionally ligated brackets. However, the data are still thin and a high need for well designed clinical trials exist.

Dental Stress Analysis↗
PubMed2002

The reproducibility of cephalometric measurements: a comparison of analogue and digital methods.

The aim of this study was to compare the reproducibility of longitudinal cephalometric measurements between analogue and digital methods using two different resolutions. Cephalometric radiographs of 20 patients were selected at the start (T1) and end (T2) of treatment: 24 cephalometric variables were calculated at T1 and T2, and their increments (T2 - T1) were also evaluated. All measurements were performed twice by two observers. Quality of methods [analogue, digital: 300 and 600 dots per inch (DPI) resolution] was evaluated by comparing the reliability coefficients and the total error between the digital and analogue methods. The inter-observer agreement was good. The 300 DPI was comparable to the analogue method. The reproducibility for the variables was comparable, but mandibular incisor increments tended to show better results with the 300 DPI method, whereas skeletal jaw relationship increments were not reliable with either method. Maxillary incisor increments, however, were reliable with both methods. The 300 and 600 DPI resolutions were found to be comparable. Scanning of cephalometric radiographs at a resolution of 300 DPI is sufficient for clinical purposes and comparable to analogue cephalometrics. However, all methods were found to be poor in assessing skeletal jaw relationships longitudinally.

Cephalometry↗
PubMed2001

Masticatory muscle function and transverse dentofacial growth.

Numerous experimental and clinical studies have shown an association between masticatory muscle function and craniofacial growth. The present series of studies focuses on the influence of masticatory muscle function on some basic mechanisms in craniofacial growth as well as on the effect of the functional capacity of the masseter muscle on the width of the maxillary dental arch in human subjects. The animal experimental model used to study the influence of masticatory muscle function was a non-invasive one that produced a decreased functional demand of the masticatory system in growing rats by feeding them a soft diet. The influence of reduced masticatory muscle function on the transversal dimensions of the premaxilla, maxilla (including the dental arch) and the calvaria was studied on dry skulls using a high precision non-contact measuring system. Moreover, a methodological study was carried out to study the influence of one preparation method on the dimensions of dry rat skulls, using axial contact radiographs. The effect of different functional demands on sutural dimensions and sutural bone apposition was studied on frontal undecalcified sections of the rat snout using automatic image analysis. For the quantification of sutural dimensions contact microradiographs were used, while for sutural bone apposition the bone level at certain time intervals was marked with calcein. In the clinical part of this thesis the relationship between maxillary dental arch width and masseter muscle thickness in humans was studied using ultrasonography. Masticatory muscle function was found to influence the transverse growth of the skull at areas under direct muscle influence as well as the dental arch width in regions with molars under eruption. The methodological study indicated that direct comparisons between measurements on fresh specimens and those on dry rat skulls are not permissible, since the dimensions of the dry rat skull are smaller than those of the original fresh specimens. The dimensions and morphology of the facial sutures as well as the sutural bone apposition were negatively affected by reduced masticatory function. The experimental findings of the present study might indicate some of the underlying mechanisms of the clinical findings, where subjects with thicker masseter muscles were found to have a broader maxillary dental arch.

Adolescent↗
PubMed2000

The influence of a 0.2% chlorhexidine mouthrinse on plaque regrowth in orthodontic patients. A randomized prospective study. Part II: Bacteriological parameters.

In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1 +/- 1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influences of a 0.2% chlorhexidine mouthrinse (Corsodyl, CHX) and a commercially available dentifrice supplementing fluoride (Odol-med-3) were compared intra- and interindividually in a crossover design with regard to the bacteriological parameters. The bacteriological parameters of vital fluorescence, bacteriological counts (BC), colony forming units (CFU), plating efficiency (PE) and mutans streptococci (MS) were related to the clinically assessed indices of plaque and gingivitis. All parameters analyzed demonstrated significant differences between the control and the test (chlorhexidine) group. Where-as the values of BC, CFU, and PE progressively increased in the control group from T0 to T2, these parameters distinctly decreased in the chlorhexidine group. All values of vital flora (VF) scored around 75% in the control group compared to values of 30% in the test group. BC, CFU und PE correlated significantly. The score of mutans streptococci persisted or increased in the controls whereas mutans streptococci approached 0 in the chlorhexidine group. Until the 5th day of washout a clear-cut carry over of the chlorhexidine rinse on mutans streptococci as well as on the gingival index was evident. Since dead microorganisms remain on the tooth surface and in order to maintain oral health, chlorhexidine application might advisedly be supplemented by mechanical plaque control.

Adolescent↗
PubMed2000

The influence of a 0.2% chlorhexidine mouthrinse on plaque regrowth in orthodontic patients. A randomized prospective study. Part I: clinical parameters.

In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1 +/- 1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influence of a 0.2% chlorhexidine (CHX) mouthrinse (Corsodyl) and a commercially available dentifrice supplementing fluoride (Odol-med-3) were compared intra- and interindividually in a crossover design with regard to plaque and gingivitis. Before starting the first test phase there was a 14-day preliminary phase for upgrading the oral hygiene. Between the 2 test phases was a 5-day "washout". On the last day of the second test phase the patients were asked to fill in a questionnaire concerning their experiences during the study. The 0.2% Corsodyl reduced the plaque index scores significantly (p < 0.001). The gingival index revealed a similar reduction (2nd day of test: p = 0.03). Until the 5th day of washout a clear-cut carryover effect of the chlorhexidine rinse on the gingival index was observed. Both the lower mean values of the 2 clinical parameters at the beginning of the test phases as compared with those at the beginning of the preliminary phase and the evaluation of the questionnaires indicated a possible Hawthorne effect. 0.2% Corsodyl may be employed as an adjunct to other preventive measures such as professional care and patient-oriented instruction on an intermittent basis in order to reduce the plaque-induced iatrogenic side effects and to enhance the efficacy of oral hygiene measures in connection with orthodontic therapy with fixed appliances.

Adolescent↗
PubMed2000

Briefing of orthodontic patients.

The aim of this study was to record the level of relevant knowledge among orthodontic patients and their parents in order to determine how they prepare for the first consultation and what level of orthodontic briefing is needed. The focus was on the response of young patients to briefing, with other objectives being to investigate what briefing media are used by orthodontists for patient motivation and improved compliance as well as the extent to which new briefing media are needed. Two hundred 9- to 12-year-old patients and their parents were interviewed, using a standardized questionnaire to record their knowledge and their need for information on orthodontic matters. In addition, 200 orthodontists were asked to fill in a questionnaire and to return it together with the briefing material used by them. The response rate was 62%.--To obtain an overview of the orthodontic briefing material available, various institutions (PR offices of health insurance companies, professional associations, specialist publishing houses, regional study groups) were approached with written requests for relevant material. Currently available children's books with dental or orthodontic subject matter were also scrutinized. 74% of children wanted to learn more about their orthodontic treatment and 40% expressed anxiety, in particular towards fixed appliances and impression-taking. 98% of orthodontists reported that the briefing interview was the main source of information. Despite being the person primarily in need of motivation, however, the child was not the focus of attention at the first consultation, even though that consultation was the preferred source of information for 51% of children. Other briefing media, consisting mainly of demonstration models and leaflets, were used primarily in the orthodontist's waiting room and surgery. Space-taking media (video films, computers) were rarely used, as were books. It is concluded that there is a clear-cut need for the orthodontic briefing process to be improved.

Audiovisual Aids↗
PubMed1999

Spontaneous uprighting of permanent tooth germs after elimination of local eruption obstacles.

Four clinical cases are presented to demonstrate the self-correcting potential of aberrant tooth germs after the elimination of eruption obstacles (in 2 cases cysts, in 2 other cases severely infraoccluded primary teeth). In the case of the submerging deciduous teeth, the tilted adjacent teeth were orthodontically uprighted after the surgical procedure. Possible causative mechanisms are discussed.

Bicuspid↗
PubMed1998

Current knowledge in cleft lip and palate treatment from an orthodontist's point of view.

The aim of this review was to put new clinical research findings into proper perspectives relative to previously accepted knowledge on treatment of patients with cleft lip and palate. The first part of the paper deals with various aspects of infant orthopedic treatment, such as its influence on primary surgery, maxillary arch form and dimensions, feeding, psychological situation of the parents and speech development. Following parts analyze general maxillofacial growth outcome after surgery and also maxillofacial growth in relation to particular surgical procedures (palatal repair, periosteoplasty/gingivoplasty, bone grafting). The last part of the review discuss the effects of certain orthodontic/orthopedic treatment approaches as well as the role of dental implants in treatment of cleft lip and palate patients.

Cephalometry↗
PubMed1998

Development of the residual cleft in the hard palate after velar repair in a 2-stage palatal repair regimen.

Delayed closure of the hard palate is believed to improve maxillary growth and facial appearance in cleft lip and palate patients. However, the cleft opening in the hard palate after velar closure might impair speech development. The aim of this investigation was to study the development of the residual cleft in the hard palate after 2-stage palatal repair (TSPR) in children born with complete cleft lip and palate (bilateral [BCLP]; n = 7 or unilateral [UCLP]; n = 22) or isolated cleft palate (CP; n = 9). Moreover, we aimed to investigate whether any morphologic factors before surgery might predict development of the residual cleft. Dental casts obtained prior to velar repair (mean age 7 months) and postoperatively at 1 1/2, 3, 4, 5 and 7 years were analyzed with a Reflex Microscope regarding the width, length and area of the cleft in the hard palate. The palatal cleft varied in size both pre- and postoperatively in all 3 types of cleft patients. The width of the cleft in the UCLP subgroup showed a marked reduction immediately after velar repair, but then, on average, remained stable until final surgical closure of the hard palate. In the BCLP subgroup the initially rather narrow width of the clefts remained unchanged postoperatively. Clefts in the CP subgroup, especially in those with a complete cleft, remained large after veloplasty. In 4 of the UCLP and 2 of the BCLP patients, the cleft width increased gradually. In some other subjects, both in the UCLP and BCLP subgroups, the residual cleft closed functionally with time, but this development could not be foreseen.

Child↗
PubMed1998

The effects of myotonic dystrophy and Duchenne muscular dystrophy on the orofacial muscles and dentofacial morphology.

This article takes a closer view of two of the less rare myopathies, myotonic dystrophy (MyD) and Duchenne muscular dystrophy (DMD). A high prevalence of malocclusions was found among the patients affected by these diseases. The development of the malocclusions in MyD patients seems to be strongly related to the vertical aberration of their craniofacial growth due to the involvement of the masticator, muscles in association with the possibly less affected suprahyoid musculature. Thus, a new situation is established around the teeth transversely. The lowered tongue is not in a position to counterbalance the forces developed during the lowering of the mandible by the stretched facial musculature. This may affect the teeth transversely, decreasing the width of the palate and causing posterior crossbite. The lowered position of the mandible, in combination with the decreased biting forces, may permit an overeruption of the posterior teeth, with increased palatal vault height and development of anterior open bite. The development of the malocclusions in DMD patients also seems to be strongly related to the involvement of the orofacial muscles by the disease. However, the posterior crossbite is not developed owing to the narrow maxillary arch, as is the case in MyD patients. On the contrary, the posterior crossbite in DMD is due to the transversal expansion of the mandibular arch, possibly because of the decreased tonus of the masseter muscle near the molars, in combination with the enlarged hypotonic tongue and the predominance of the less affected orbicularis oris muscle.

Biomechanical Phenomena↗