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Biomedical subjects

A Tallgren

Publications and source records attributed to A Tallgren.

At least 19 recordsLinked to original sources
PubMed1998

Effects of a myofunctional appliance on orofacial muscle activity and structures.

The aim of the study was to examine the effect of an oral shield treatment on orofacial muscle activity and facial morphology in children with lip and/or tongue dysfunction. The sample consisted of 7 girls and 2 boys, 7 to 12 years old. EMG recordings with and without the shield in situ were obtained when the shield was placed, and 3, 6, and 12 months later. Lateral cephalograms were obtained at the initial and 1-year stages. The lip muscles showed dominant activity when the subjects were sucking on an empty straw and during swallowing; this was strongest during the first 3 months. The mentalis, buccinator, and digastric muscles generally showed weaker activity. The anterior temporal muscle showed dominant activity during maximal clench, but after the 3-month stage a significant decrease was noted. After 1 year of treatment, no significant changes in overjet or overbite were observed. Most of the craniofacial growth changes were normal for the age group. The results indicate that treatment with an oral shield caused a decrease in orofacial muscle activity during oral functions. Although there was a slight average retraction of the maxillary incisors, the change in position was not statistically significant.

Cephalometry↗
PubMed1995

Relationships between facial morphology and activity of orofacial muscles in patients with a complete upper and a partial lower denture.

In a sample of 30 partially edentulous subjects, provided with an immediate complete upper denture and a partial lower denture and followed for 2 years, a correlation analysis was performed between facial morphology, as measured by lateral head films, and EMG peak mean voltages of the anterior temporal and masseter muscles when clenched and during swallowing and chewing, and of the lip muscles during swallowing. At the pre-treatment stage, when the patients occluded on a residual anterior dentition, correlations between facial morphologic characteristics and peak mean voltages of the jaw closing muscles indicated stronger muscle activity in individuals with a square facial type. No significant associations were observed between muscle activity and the age of the subjects, which ranged from 36 to 71 years. After placement and use of the dentures a significant forward-upward rotation of the mandible with a decrease in overbite occurred, as a result of resorption of the edentulous maxillary ridge. At the 1 year stage of denture use, the elevator activity showed no significant correlations with facial morphology. On the other hand, negative correlations were observed especially between the anterior temporal activity and anterior overbite. Similar negative correlations were observed for the lip activity during swallowing, especially of the upper lip. These findings suggest occlusal contact between the incisors during the various functions in subjects with a small overbite. The findings further suggest that the anterior temporal and the upper lip muscles are sensitive to changes in anterior occlusal relations of the dentures.

Adult↗
PubMed1993

Head posture in obstructive sleep apnoea.

In growing subjects, obstruction of the upper airway may lead to excessive vertical facial development. According to the soft-tissue stretching hypothesis (Solow and Kreiborg, 1977) this could be due to an increased cranio-cervical angulation triggered by the airway obstruction. The present study aimed to examine the effect of airway obstruction on cranio-cervical posture in a sample of adult patients with severe obstructive sleep apnoea (OSA). Lateral cephalometric radiographs taken in the natural head position (mirror position) were obtained from 50 male patients aged 28-70 with polysomnographic diagnosis of obstructive sleep apnoea. The Apnoea Index ranged from 21 to 98 episodes per hour with a mean of 54.6. Control samples were available from previous cephalometric studies of head posture in five samples of healthy subjects and one sample of congenitally blind subjects. The average cranio-cervical angle, NSL/OPT, was found to be extremely large (mean 104.1, SD 9.1) exceeding the average values in the control samples by 1-2 standard deviations (P < 0.001). It is suggested that the large cranio-cervical angle in OSA patients is a physiological adaptation aiming to maintain airway adequacy while the head, and thus the visual axis, is kept in its natural relationship to the true vertical. The findings thus provide evidence for the hypothesis that upper airway obstruction may trigger an increase in the cranio-cervical angulation.

Adaptation, Physiological↗
PubMed1992

Swallowing activity of lip muscles in patients with a complete upper and a partial lower denture.

In 30 partially edentulous subjects provided with an immediate complete upper and a partial lower free-end denture the lip activity in swallowing was studied before and after denture treatment and during a 2-year period of denture wearing. Electromyographic recordings of the right side upper and lower orbicularis oris, mentalis and anterior temporal muscles were obtained during swallowing saliva and during swallowing of water with and without the dentures in the mouth. In the different types of swallows recorded, the lower lip and mentalis muscles showed much stronger activity than the upper lip and anterior temporal muscles and also initiated the swallowing activity. No significant changes in mean voltages of the swallowing activity were observed during the 2-year observation period. On the other hand, the durations of the swallows showed marked increases after 1 year of denture use, when no further rebasings of the complete upper denture had been made.

Adult↗
PubMed1991

Age differences in adult dentoalveolar heights.

A previous study of age differences in facial morphology in a dentate sample representing young, middle, and old age (Tallgren and Solow, 1987) indicated an increase in lower anterior face height during adulthood. The aim of the present study was to examine in detail the accompanying age differences in dentoalveolar heights. The material consisted of lateral head films of 191 dentate Finnish women divided into the age groups 20-29, 30-49, and 50-81 years. The present study comprised 26 variables calculated from digitized reference points. The maxillary and mandibular anterior dentoalveolar heights were significantly larger in the middle and old age groups than in the young group, and the mean differences were of the same magnitude for the maxilla and the mandible. Analysis of the dentoalveolar components showed that in the mandible the extra-alveolar height of the incisors was significantly larger in the two older age groups than in the young group, while no significant differences were found in the maxilla. The mean differences in anterior mandibular ridge height between the older age groups and the young group were smaller than in the maxilla. No significant differences in dentoalveolar morphology were observed between the middle and the old age groups.

Adult↗
PubMed1991

Chewing and swallowing activity of masticatory muscles in patients with a complete upper and a partial lower denture.

The chewing and swallowing activity of jaw-closing muscles was studied longitudinally in 30 partially edentulous subjects who were provided with an immediate complete upper and a partial lower denture. Electromyographic recordings of the anterior temporal and masseter muscles were obtained during habitual chewing of apple and during swallowing of saliva and water, before final extractions and 7 weeks, 6 months, 1 year and 2 years after denture insertion. At the pre-treatment stage, when the patients were chewing with a residual anterior dentition, the mean voltages showed low values compared to findings reported in subjects with a complete natural dentition. After 6 months of denture use, the chewing forces showed significant increases in amplitude, and the increased force of contraction persisted to the 2-year stage. The recordings of swallowing revealed no significant changes in maximal mean voltage during the observation period. However, there was a significant increase in the duration of the swallows after 1 year of denture wearing, which might be related to stabilization of the complete upper denture due to continuing resorption of the maxillary ridge.

Adult↗
PubMed1989

A two-year kinesiographic study of mandibular movement patterns in denture wearers.

Changes in functional jaw movements during a 2-year period of denture wear were investigated. The sample consisted of 27 partially edentulous subjects who were provided with an immediate complete maxillary denture and a removable partial mandibular denture. Recordings of habitual chewing of apple and empty open-close cycles were made with a mandibular kinesiograph. At the pretreatment stage, when the patients occluded on a residual anterior dentition, irregular patterns of movement were observed. After placement of the dentures, which restored posterior occlusion, the chewing and open-close patterns showed marked improvement and were characterized by significant mean decreases in sagittal and transversal range of movement. Relining of the maxillary dentures further stabilized the functional patterns. During the second year, significant reductions in vertical range of movement and lateral chewing excursions were observed, and were probably related to impaired retention of the complete upper denture.

Adult↗
PubMed1989

A 2-year electromyographic study of patients with an immediate complete upper and a partial lower denture.

A longitudinal electromyographic (EMG) investigation was performed on thirty subjects provided with an immediate complete upper and a partial lower denture. Electromyographic recordings in maximal clench, light tapping and postural position were obtained from the anterior temporal and masseter muscles before final extractions and 7 weeks, 6 months, 1 year and 2 years after denture insertion. The maximal clench activity of the jaw closing muscles showed an average tendency to decrease upon insertion of the dentures, but thereafter significant increases in mean voltages were observed during the first year of denture wear. During the second year no significant changes in EMG clenching force were noted. At the 2-year stage most of the muscles showed significantly greater clench activity than at the post-insertion stage, but did not exceed the pre-extraction level. The jaw muscle activity in light tapping showed no significant mean changes during the observation period. The postural activity tended to decrease during the period of denture wear, the decrease being significant for some of the muscles at the 2-year stage.

Adult↗
PubMed1987

Follow-up study of silent periods in complete denture wearers.

Electromyographic silent periods in response to chin taps during clench were recorded from the anterior temporalis and masseter muscles. Ten complete denture wearers were observed up to the 1-year stage of denture wear and eight patients up to the 2-year stage. Silent periods were also recorded from patients clenching on paper rolls in place of the dentures. Regarding the patterns of the silent periods, similar observations of double silent periods were made as in our previous study up to the half-year stage of denture wear (McCall, Tallgren & Ash, 1979). The frequency of the double silent periods was 13.8% at the 1-year stage and 7.3% at the 2-year stage. The mean duration of the silent periods did not differ significantly at the 1-year and 2-year stages. The mean silent period duration when clenching on paper rolls without dentures in the mouth was significantly shorter than when clenching with the dentures.

Adult↗
PubMed1986

Changes in jaw relations and activity of masticatory muscles in patients with immediate complete upper dentures.

A longitudinal radiographic cephalometric and electromyographic investigation was performed on eighteen subjects provided with an immediate complete upper and a partial lower denture. The observation stages were: before final extractions and 7 weeks, 6 months and 1 year after denture insertion. The cephalometric analysis was based on measurements from lateral head films taken in centric occlusion. The EMG activity of the anterior temporal and masseter muscles was studied in postural position, light tapping and in maximal clench. The changes in jaw and occlusal relationships due to resorption of the edentulous maxillary ridge were slight, the mean decrease in occlusal vertical dimension during one year being 0.7 mm. The EMG clench activity at the pre-extraction stage, when the patients occluded on a residual anterior dentition, showed low mean values round 100 microV, and a further decrease was observed at the post-insertion stage. At the 1-year stage all muscles displayed significant increases to above the post-insertion level. The jaw muscle activity in light tapping and in postural position generally showed no significant mean changes during the observation period. The results indicate that preservation of a residual dentition in the lower jaw prevents marked changes in jaw and occlusal relationships and resulting changes in muscle activity.

Adult↗
PubMed1984

Long-term changes in hyoid bone position and craniocervical posture in complete denture wearers.

Changes in hyoid position in relation to changes in mandibular inclination and craniocervical posture were studied by roentgen cephalometrics in a sample of 24 long-term complete denture wearers over a 15-year period. The measurements were made on lateral occlusion films obtained with the subjects in the sitting position and with the head oriented according to its natural balance. The changes in mandibular inclination ranged from -5.5 degrees to 8.6 degrees, with a mean of zero. The cervical column became significantly more forward inclined (mean, 5 degrees), and the craniocervical angulation became on an average 5 degrees larger. Correlation analyses indicated that the hyoid position was influenced by two postural systems: the changes in mandibular inclination and the changes in cervical and craniocervical posture. The vertical changes in hyoid position in relation to the upper face largely followed the patterns of increase or decrease in mandibular inclination, whereas the horizontal changes mainly followed the changes in cervical inclination and craniocervical angulation.

Adult↗
PubMed1983

Changes in jaw relations, hyoid position, and head posture in complete denture wearers.

In a group of 18 partially edentulous patients provided with immediate complete dentures, changes in hyoid bone position and craniocervical posture were examined on cephalometric radiographs made during 1 year of denture use. The findings indicated that the changes in hyoid bone position largely followed the pattern of forward-upward rotation of the mandible due to ridge resorption. During this course the hyoid position in relation to the cervical spine showed a mean increase. The hyocervical changes, however, showed less variability than the hyomaxillary and hyomandibular changes. The posture of the head and cervical column showed no definite mean changes during the 1-year period. On the other hand, analysis of individual changes revealed that a pronounced decrease in mandibular inclination due to ridge resorption was associated with retroclination of the cervical column and decreased craniocervical angulation. These postural changes may be regarded as adaptive changes to a marked initial change in mandibular position.

Adult↗
PubMed1983

Correlations between EMG jaw muscle activity and facial morphology in complete denture wearers.

In a sample of fifteen partially edentulous subjects assigned for immediate complete denture treatment, a correlation analysis was performed between pre-extraction facial morphology determined from lateral cephalograms, and EMG activity of the anterior temporal and masseter muscles in maximal clench and tapping of teeth. Marked correlations observed between vertical and sagittal jaw relations and mean voltages of the jaw-closing muscles indicated strong biting activity in subjects with a square facial type. No significant associations were observed between biting strength and the age of the subjects. Correlations between facial morphological changes and changes in EMG biting activity after denture insertion and during 1 year of denture wear indicated that the anterior temporal muscles were extremely sensitive to sagittal changes in anterior occlusion. The masseter muscles were less sensitive, but responded in some instances to changes in vertical jaw relationship.

Adult↗
PubMed1980

Jaw muscle activity in complete denture wearers--a longitudinal electromyographic study.

EMG study of subjects wearing immediate complete upper and lower dentures revealed marked alterations in activity of the jaw closing muscles during the biting actions recorded. This finding suggests that changes in jaw and occlusal relationships due to resorption of residual ridges and settling of the dentures also affects jaw muscle activity. The relations between EMG and morphologic findings will be analyzed further in a separate article.

Adult↗
PubMed1980

Roentgen cephalometric analysis of ridge resorption and changes in jaw and occlusal relationships in immediate complete denture wearers.

In eighteen subjects assigned for immediate complete upper and lower dentures, roentgen cephalometric recordings were made before extraction of the residual anterior dentition and 3 weeks, 3 months, 6 months and 1 year after denture insertion. The cephalometric analysis was based on electronic measurements of linear and angular morphological variables and computer head plots generated from 177 reference points (Walker, 1967), derived for each subject for each of the five observation stages. The reduction of the alveolar ridges was most rapid during the first 3 months of denture wear and particularly during the post-extraction period of 3 weeks. The reduction in anterior height of the lower ridge was on average twice as great as that of the upper ridge. The ridge resorption and the accompanying settling of the dentures on the basal seats, measured from lead shots inserted in the dentures, brought about an upward rotation of the mandible with a resulting decrease in occlusal vertical dimension and reduction in overjet of the dentures. In accordance with the amount of ridge reduction, these changes showed great individual variation.

Adult↗
PubMed1979

An electromyographic and roentgen cephalometric study of occlusal morphofunctional disharmony in children.

In a sample of children with dual bite and symptoms in the masticatory system, the activity of the anterior temporal and masseter muscles was studied electromyographically during clench and light tapping in the posterior occlusal contact position and centric occlusion and in protrusive bite on the incisors. The findings indicated that the optimal muscle function during maximal clench and tapping with displayed in the posterior occlusal contact position, which in the present subjects was situated, on the average, 0.5 to 1 mm. anterior to the centric jaw relation. It should therefore be recommended that, in orthodontic treatment of children with dual bite, the intercuspal position (centric occlusion) should be established in the posterior occlusal relationship. This is in accordance with the opinion of several authors who have emphasized the use of the retruded contact position (the centric jaw relation) as key reference position in orthodontic treatment and occlusal rehabilitation. These authors have further emphasized the importance of stable occlusal contacts in centric relation, centric occlusion, and the various jaw excursions in obtaining and maintaining a harmonious function between the dentition, the temporomandibular joints, and the neuromuscular system.

Adolescent↗
PubMed1979

EMG silent periods in immediate complete denture patients: a longitudinal study.

Jaw muscle silent periods in response to chin taps were recorded from immediate complete denture patients before extraction of a residual anterior dentition, after insertion of the dentures, and three and six months after insertion. After three months' use of the dentures, the mean EMG silent period duration was significantly increased compared to the pre-extraction stage.

Adult↗