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Biomedical subjects

S Kiliaridis

Publications and source records attributed to S Kiliaridis.

At least 55 records · Page 3Linked to original sources
PubMed1993

Comparison of the prevalence, severity and possible causes of occlusal tooth wear in two young adult populations.

Most reports of the prevalence and severity of tooth wear in contemporary Western populations claim that advanced wear in uncommon by comparison with certain non-Western populations. Differing methods of wear evaluation in the various studies, however, preclude accurate comparisons from being made. This study records mean total and segmental wear indices obtained from the casts of a selected Swedish patient population sample, and age- and sex-matched Saudi high-wear and random samples. The wear experience of the Saudi random sample compared favourably with that of the Swedish selected one, while the wear of the Saudi high-wear sample was significantly higher than that of the Swedish sample (P < 0.01). The findings from a questionnaire revealed certain significant correlations between aetiological factors and wear, most notably, the relatively greater presence of bruxism (P < 0.01), absence of biting habits and minimal cola consumption (P < 0.01) in the Swedish sample. Harsh environmental and climatic conditions probably account for the Saudi experience of high wear.

Adolescent↗
PubMed1993

Covariation of some factors associated with occlusal tooth wear in a selected high-wear sample.

The aim of the present study was to investigate the significance of some factors associated with occlusal tooth wear in a selected high-wear Swedish sample. The material comprised 59 subjects having a mean age of 35 yr within the range 16-70 yr, the criteria for selection being a full or nearly full complement of natural teeth, and the presence of definite clinical signs of occlusal wear. A dentition wear index was derived from a tooth-by-tooth evaluation of casts. The results showed that men had significantly greater wear than women. Other factors which were found to correlate significantly with increased occlusal wear were: age, increased bite force, decreased occlusal tactile sensitivity, increased endurance time, and reduced tendency for crowding in the dental arches. In the salivary analysis, it was found that low buffer capacity and low rate of secretion were significantly correlated with high wear. Cephalometric variables shown to be correlated with increased wear were retroclination and position of maxillary incisors, and greater interincisal angle. The results from this study also suggest that the associations of attrition with certain dentoalveolar morphologic features are similar in the present contemporary sample and various noncontemporary populations.

Adolescent↗
PubMed1993

An investigation of some factors associated with occlusal tooth wear in a selected high-wear sample.

The aim of the present study was to investigate the influence of some factors associated with occlusal tooth wear in a selected high-wear Swedish sample. The material comprised 59 persons having a mean age of 35 yr within the range 16-70 yr, the criteria for selection being a full or near-full complement of natural teeth, and the presence of definite clinical signs of occlusal wear. A dentition wear index, in addition to anterior, posterior, and arch subindices, was derived from a tooth-by-tooth evaluation of casts. Factors which were found to correlate significantly with increased occlusal wear were age, sex, self-perception of wear, number of teeth, and general health, as well as a number of variables from study-cast analysis. On the basis of the findings, not only is the multifactorial etiology of occlusal tooth wear a reality, but so, too, is the complex interdependence of these factors in the severity of wear.

Adolescent↗
PubMed1993

The relationship between maximal bite force, bite force endurance, and facial morphology during growth. A cross-sectional study.

The aims of this investigation were to study the relation between facial morphology and bite force at different ages during growth and to investigate possible relations between bite force and the variables age, finger force, stature, and sex in growing healthy individuals. One hundred and thirty-six individuals were included, consisting of six groups of males and females, 7-9, 10-12, and 20-24 years old. Standardized photographs were taken to determine the facial type. The occlusal relationship, body height, finger force, maximal bite force, and bite force endurance amplitude were recorded. All bite force variables and finger force increased with age in both sexes. A positive correlation was found between the maximal bite force in the incisor region and the ratio of upper to lower facial height; this is, subjects with a high bite force had a relatively short lower anterior height. The maximal bite force for molars and endurance amplitude were positively correlated to stature and finger force but not to facial characteristics. A longitudinal study to follow each individual child during growth would be of interest to evaluate the importance of muscular influence on facial growth.

Adult↗
PubMed1992

Influence of masticatory muscle function on craniofacial growth in hypocalcemic rats.

The aim of this study was to investigate the influence of low masticatory function on the craniofacial growth pattern in rats fed a low calcium and vitamin D deficient diet. Male growing rats were divided randomly into three groups: the Normal Hard Diet group, the Deficient Soft Diet group, and the Deficient Hard Diet Group. Lateral cephalograms were taken at days 0, 14 and at the end of the experiment, day 28. The craniofacial growth pattern was altered by an upwards rotation of the viscerocranium (orthocranialization) in the Deficient groups and, the total skull lengths were shorter than in the Normal Hard Diet group. The viscerocranium in the Deficient Soft Diet group was in an even more orthocranial position than in the Deficient Hard Diet group and the antegonial notch was shallower. This indicates that an induced disturbance of craniofacial morphology due to metabolic bone disease during growth is accentuated by a low masticatory function.

Animals↗
PubMed1991

Masseter muscle thickness measured by ultrasonography and its relation to facial morphology.

The aims of this study were to evaluate ultrasonography as a method for measuring masseter muscle thickness, to quantitate the normal range of the ultrasonically measured thickness of the masseter in adults, and to test whether the variation in the thickness of the muscle is related to the variation in the facial morphology in different individuals. In 40 healthy, fully-dentate young adults, 20 men and 20 women, the masseter thickness was measured bilaterally by a real-time ultrasound imaging technique. The measurements were performed under both relaxed conditions and with maximal clenching. Standardized facial photos of the subjects were taken so that their facial morphology could be determined. The measurement error of the thickness of the masseter was found to be small, not exceeding 0.49 mm. Under relaxed conditions, the mean thickness (+/- S.D.) of the muscle in men was 9.7 (+/- 1.5) mm, and under contracted conditions, 15.1 (+/- 1.9) mm. In women, the respective measurements were 8.7 (+/- 1.6) mm and 13.0 (+/- 1.8) mm. The thickness of the masseter muscle was found to be related to the facial morphology, mainly in women, but not in men; the women with a thin masseter had a proportionally longer face. Ultrasonography was found to be a reliable and accurate method for study of the thickness of the masseter muscle. There was a large variation in the thickness of the muscle between individuals, and the thickness of the masseter was related to facial morphology in women.

Adult↗
PubMed1991

Characteristics of masticatory mandibular movements and velocity in growing individuals and young adults.

Studies of the development of mastication in the normal growing individual have received little attention in the literature. The aim of this study was to determine whether changes in oral motor function occurred during growth. Ninety healthy individuals with normal occlusion were divided into six groups of males and females, 9-10, 13-15, and 20-22 years of age. Oral motor function, with respect to mandibular displacement and velocity, was monitored with an opto-electronic method. The results revealed that the total duration of the masticatory cycle was not influenced by age or gender. However, the time distribution between the different phases was found to be influenced by the age factor, causing a longer opening time and a shorter closing time in the adults. In mastication, both mandibular displacement and the mandibular velocity in closing were less in females. A reduction of the masticatory opening velocity and an increase in closing velocity were observed with increasing age. Physiological maturation of the masticatory system due to central and peripheral changes and functional adjustments due to changes in dentition and skeletal growth may be the underlying reasons for our findings.

Adolescent↗
PubMed1991

Dental needs of patients with myotonic dystrophy.

The aim of this study was to assess oral health and motoric ability in persons with myotonic dystrophy in comparison with a control group of healthy persons and find out whether an increased need of dental care exists in persons with reduced motoric ability. Twenty-seven persons, mean age 45, with the diagnosis myotonic dystrophy were compared with an age- and sex-matched control group. The dental status was determined from orthopantomograms and bite-wing radiographs. Oral hygiene, using a simplified index, periodontal pocket depth and alveolar bone height were recorded. Additionally, the finger force of the patient was recorded in order to evaluate the muscular capacity. Compared to control persons, persons with myotonic dystrophy had a lower finger force. They also had fewer teeth, higher caries frequency and more plaque, although no difference was found in the alveolar bone support around their remaining teeth. A positive correlation was found between finger force and oral hygiene. Persons with myotonic dystrophy had a decreased ability to maintain good oral hygiene, possibly due to motoric disability, and they had an increased need of dental hygienic care.

Adult↗
PubMed1990

Anterior open bite treatment with magnets.

The aim of this study was to examine the effects of repelling magnets on the treatment of anterior open bite and compare them with the effects of acrylic posterior bite-blocks. Twenty patients, aged 9-16 years with skeletal anterior open bite, were randomly divided into two groups. In one group the patients wore posterior repelling magnet splints and in the other they wore acrylic posterior bite-blocks of the same thickness as the magnet splints. The patients were instructed to use their appliance as much as possible (the minimum accepted being 18 hours daily) during a 6-month period. Dental casts, intra-oral photos, and lateral cephalograms were taken before and after treatment, and the patients were also examined regularly to identify the development of any craniomandibular disorders. In the first group, the dental and skeletal vertical relation responded quickly to the magnet treatment. The open bite was generally closed in just under 4 months, especially in patients in early mixed dentition. Spacing in the labial segments decreased in some cases, while slight crowding was induced in others. Transverse problems, i.e. unilateral cross-bite, sometimes followed by scissor-bite on the opposite side, was observed in those patients who were in the early mixed dentition and had used the magnets intensively. The patients who wore acrylic posterior bite-blocks also showed improvement in the dental and skeletal vertical relationships, especially during the first months. This was followed by a 'plateau' period. No transverse problems were found in these patients.

Acrylic Resins↗
PubMed1990

Short-term and long-term effects of chewing training on occlusal perception of thickness.

The aim of this study was to investigate the short-term and long-term effects of functional stimuli, induced by intense chewing and by prolonged systematic chewing training, on the response of occlusal perception of thickness. The material comprised 25 young adults divided into an experimental group (17) and a control group (8). The occlusal perception of thickness was tested by successively placing different thicknesses of aluminum foil between five pairs of occluding teeth, i.e. right and left second premolars and canines and one pair of the central incisors. The experimental group was tested 2 wk before the start of the experiment and at the start and the end of the experiment, i.e., after 4 wk systematic chewing training, and before and after 30 min intense chewing. The control group was tested on the same occasions but without performing any special chewing activity. The discrimination threshold increased in most of the subjects after 30 min of chewing, both before and after the 28-day training period. This threshold increase was found in all groups of teeth tested. No changes were found in the discrimination threshold of the teeth tested after 28 days of chewing training. In the controls no differences were found between the recording occasions. Since no statistically significant differences were observed between the groups of teeth tested, the changes in the threshold of occlusal perception after intense chewing may reflect the influence of receptors other than periodontal, for example those in TMJ and muscles, which are involved in the control of other neuromuscular mechanisms such as those that control the postural position of the mandible.

Adult↗
PubMed1989

Muscle function and craniofacial morphology: a clinical study in patients with myotonic dystrophy.

The occlusal traits and the craniofacial morphology were studied in patients with an altered muscle function caused by myotonic dystrophy. Twenty-four adult patients were examined and compared with a matched group of healthy individuals. The condition of the masticatory muscles was evaluated by measuring the maximal bite force. The dental arches and the occlusal traits were analysed on dental casts. Lateral cephalograms were taken in the patients with myotonic dystrophy to study the craniofacial morphology. It was found that the patients suffering from myotonic dystrophy had weak masticatory muscles, which might be caused by the disease. A high prevalence of malocclusions (postnormal occlusion, anterior open bite and lateral cross bite) was found among these patients. Their craniofacial morphology showed a vertical aberration, characterized by a large angle between the mandibular and palatal planes and a steep mandible. These findings seem to be most pronounced in patients with an early onset of the disease and support the hypothesis that reduced muscle function may cause changes in the craniofacial morphology.

Adult↗
PubMed1989

Muscle function as a determinant of mandibular growth in normal and hypocalcaemic rat.

The aim of the present investigation was to study the influence of low muscle function on the form, growth and structure of the mandible in rats with a metabolic bone disturbance due to hypocalcaemia. Growing rats were randomly divided into four groups where two factors were combined: hard or soft diet consistency to normal or calcium deficient diet. The experimental period was 30 days. At day 0 and day 15 the animals were injected with oxytetracycline. At the end of the experiment X-rays were taken from the mandibles for cephalometric analysis and the bone remodelling pattern was studied under a fluorescence microscope and with help of microradiograms. The cephalometric analysis showed that calcium deficiency was an unfavourable factor for the growth of the mandible as a whole, while muscle function was a significant factor affecting the angular and the condylar processes. General decreased bone apposition and increased endosteal resorption were found in the two calcium deficient diet groups. The cortical bone in these groups was thinner and the trabecular system sparser than in the two normal diet groups. The hard diet groups had higher bone apposition rate and better organized trabecular system than the respective soft diet groups. It was concluded that changes in the mechanical strain environment of the mandible, caused by reducing the vigorous mastication, is a powerful determinant of remodelling behaviour at certain sites, even in situations when a metabolic bone disturbance exists.

Animals↗
PubMed1989

Effect of chewing training on mandibular postural position.

The inter-occlusal rest space (free-way space) was studied before and after short and long periods of chewing of a hard resin in 15 healthy subjects. During a month of daily training for one hour of chewing no significant changes in the interocclusal rest space were seen. After 30 min of intense chewing the mean interocclusal distance increased to about twice its original size. This occurred both before and after the training period. In a control group of eight subjects without any chewing exercise no significant changes in the interocclusal rest space were noticed during the observation period.

Dental Occlusion↗
PubMed1989

Effect of chewing training on masticatory efficiency.

A special, hard chewing gum was used to study the effects of chewing training on masticatory efficiency. An experimental group of 17 individuals used this chewing gum 1 h daily for 28 days, while a control group of 8 individuals performed no chewing-gum training. The percentage of masticatory efficiency was measured with a special sieve system, and the time for 10 chewing cycles was taken from EMG recordings. These measurements were made in trained and untrained condition before and after 30 min of intense chewing. The results indicate that intense chewing for 30 min decreased the masticatory efficiency and increased the frequency of the chewing cycles significantly in both trained and untrained individuals, possibly due to fatigue of the masticatory muscles. However, chewing training for 28 days did not influence these factors significantly.

Adult↗
PubMed1988

Isometric muscle tension generated by masseter stimulation after prolonged alteration of the consistency of the diet fed to growing rats.

The forces developed by the masseter muscle and the diet-related changes were studied in situ. The active tetanic tension was measured indirectly by recording the forces applied to the mandible in four different predetermined interincisal distances. The highest tension developed in all the experimental groups was with an interincisal distance of 11 mm. The tetanic tension was significantly lower in rats fed a soft diet than in those fed a normal diet. This difference might be due to the smaller muscle fibres in rats with decreased functional demand. The changes in the masticatory muscles may influence the tension applied to the facial skeleton and cause the alteration in the craniofacial growth previously found in rats fed a soft diet.

Animals↗
PubMed1988

Histochemical analysis of masticatory muscle in the growing rat after prolonged alteration in the consistency of the diet.

Changes in muscle function induce alteration in craniofacial bone growth. To study morphological changes after alteration of masticatory function, NADH-TR reductase and myofibrillar Ca2+-activated ATPase were assessed histochemically, after alkaline and acid pre-incubation, in sections from the anterior deep masseter and the anterior digastric muscles. Type IIA, IIB and transitional fibres of the anterior deep masseter but not of the digastric muscle were smaller in a soft-diet group than in a normal-diet group. There was a small percentage of type IIA fibres and a large percentage of type IIB fibres in the anterior deep masseter in the soft-diet than in the normal-diet group. The elevator muscles do not encounter the same functional demands on a soft as on a normal diet, and this causes different biting and chewing loads, which may in turn induce skeletal changes.

Animals↗