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Biomedical subjects

U Thüer

Publications and source records attributed to U Thüer.

At least 19 recordsLinked to original sources
PubMed1999

Pressure from the lips on the teeth during speech.

Pressure on the teeth from the labial soft tissues during the articulation of a given sentence was measured in 24 children, 8 to 14 years old, with normal incisor relationships. The points of measurement were labial in the midlines between the maxillary and mandibular central incisors and between the right maxillary canine and first premolar (the modiolus point). A mouthpiece was attached to the teeth at these three positions and connected via a water-filled system to an extraoral pressure transducer. A microphone recorded the volume and speed of articulation while the activity of the lip muscles was surveyed by electromyography. The maximal pressure during pronunciation of the consonant /p/, the pressure at rest (RP), the speech posture pressure (SPP), the time pressure integral (TPI), and the mean speech pressure (MSP) during articulation were analyzed. Maximal pressure during pronunciation of /p/ and TPI were highest at the modiolus, second highest at the lower midline, and lowest at the upper midline. RP and SPP were highest at the lower midline. SPP was 2 to 3 times higher than RP, and MSP was 4 to 7 times higher than RP. The pressures during articulation recorded at the lower midline were closely correlated with those at the modiolus, with weaker correlations between the upper and lower midlines and between the upper midline and modiolus. There was a close correlation between RP and SPP. SPP, MSP, and TPI may, along with RP, contribute to the positions of the teeth.

Adolescent↗
PubMed1999

Cheek and tongue pressures in the molar areas and the atmospheric pressure in the palatal vault in young adults.

The pressures acting on the maxillary and mandibular posterior teeth from the tongue and cheeks were measured in 24 adults aged 22-29 years. In addition, the pressure in the palatal vault was recorded. The pressure at two maxillary (buccal and lingual) and two mandibular (buccal and lingual) measuring points, and in the palatal vault was recorded simultaneously. Repeated recordings of the pressures at rest, and during chewing and swallowing were made. The pressures at rest were of similar magnitude (about 2 g/cm2) at the buccal and lingual sides of the mandibular posterior teeth. The median resting pressure at the maxillary posterior teeth was 2.7 g/cm2 on the buccal side and 1.0 g/cm2 on the lingual side. The difference in the maxilla was significant, but not in the mandible. It was concluded that the equilibrium of tooth position is maintained by the pressure from the cheeks and the tongue. During chewing and swallowing the pressures on the lingual side of the teeth were greater than those on the buccal side. At rest about half of the subjects had a negative pressure at the palatal vault, but no correlations between the resting pressure at the palatal vault and the resting pressures on the teeth were found.

Adult↗
PubMed1998

No effect of lip bumper therapy on the pressure from the lower lip on the lower incisors.

The pressures from the lower lip on the lower incisors were measured at the midline between the central incisors and between the left lateral incisor and canine. The measurements were made with the lip at rest and during swallowing of water in 24 boys and 40 girls aged 9-15 years. The children were divided into four groups, two treated with a lip bumper with and without an oral shield, and two with a lingual arch with and without springs for proclination of the lower incisors. Recordings of the pressures were made before the start of the treatment, and 3 and 8 months after the use of the appliance, as well as 4 months after the removal of the lip bumper or lingual arch. The treatment with a lip bumper did not change the pressure from the lip on the lower incisors at rest. The pressure at the midline during swallowing was also unaffected by the lip bumper therapy, but the pressure between the lateral incisor and canine increased. Thus, lip bumper therapy did not lead to decreased pressure from the lip on the incisors. Proclination of the lower incisors with a lingual arch resulted in an increase of the pressure from the lip at rest. Thus, no adaptation of the lower lip to the proclination occurred. After relapse of the proclination the pressure from the lip decreased to a value no different from that before the start of the treatment.

Acrylic Resins↗
PubMed1996

Lip repair according to the principles of Delaire. What is its significance?

45 patients with UCLP/UCL and BCLP/BCL had a lip repair at a mean age of 4 months according to the principles of Delaire from 1989 to 1993. Their aesthetic results and the influence upon growth and symmetry of the face was evaluated by standardized checking of possible negative points of the lip, nose and alveolus, by measuring different distances of the mid-face in standardized photographs and by comparing the data with the literature. The aesthetic results are equal to other studies and there are some indications of a better stimulation of growth and harmonization of the face.

Cleft Lip↗
PubMed1995

Stability and effect on the soft tissue profile of mandibular setback with sagittal split osteotomy and rigid internal fixation.

The stability and the effect on the soft tissue profile of mandibular setback with sagittal split osteotomy and rigid internal fixation was studied prospectively in 29 consecutive patients, 17 to 55 years old, who had mesial occlusion. Profile cephalometric radiographs were taken immediately before and short after surgery as well as 14 months postsurgically. The mean setback of the mandible 1 to 8 days after surgery was 6.0 mm. On average, there was also a small decrease in the anterior facial height. The setback relapsed an average of 1.1 to 1.3 mm, so that at the follow-up the mean net effect was 80%. In eight patients, however, the mandible had retruded slightly further. During the follow-up period there was a further small decrease in the anterior facial height. The net effects on the labial fold and the soft tissue chin were closely correlated with those on their underlying hard structures. On average, the labial fold and the chin followed the hard structures to 106% and 107%, respectively. The mean net effect for the lower lip was only 88% of the setback of the mandibular incisor. The soft tissue facial height followed the decrease in the skeletal facial height to 60%. The setback procedure also affected the upper lip, which, on average, retruded and lengthened 1.0 to 2.0 mm.

Adolescent↗
PubMed1994

Stability and effect on the soft tissue profile of mandibular advancement with sagittal split osteotomy and rigid internal fixation.

The stability and the effect on the soft tissue profile of mandibular advancement with sagittal split osteotomy and rigid internal fixation was studied prospectively in 30 consecutive patients, 17 to 32 years old, who had a distal occlusion. Profile roentgen cephalometric recordings were made immediately before and shortly after surgery as well as 13 months postsurgically. The mean advancement of the mandible 3 to 8 days after surgery was 5 mm. On average, there was only a small increase in the anterior facial height. At the follow-up after 13 months, the advancement of the mandible had, in most cases, partially relapsed so that the median net effect was 70%. In six subjects, however, the mandible had advanced slightly further. The skeletal relapse was partially masked by compensatory movements of the maxillary incisors so that the mean net effect on the overjet was 83%. The amount of relapse was positively correlated to the magnitude of advancement during surgery. Likewise, a postsurgical relapse of the anterior facial height was positively correlated to the magnitude of advancement during surgery. Likewise, a postsurgical relapse of the anterior facial height was positively correlated to the magnitude of the vertical surgical displacement anteriorly and posteriorly. The soft tissue chin closely followed the underlying hard tissue. The mean net effect on the labial fold, however, was smaller, 88% of the mandibular advancement. The net effect on the lower lip was 66% of the advancement of the mandibular incisor.

Adolescent↗
PubMed1992

Mandibular displacement in Angle Class II, division 2 malocclusion.

The effect of the treatment of Angle Class II, Division 2 malocclusion was studied in 22 children by x-ray cephalometry and by recording the relation between the retruded and the intercuspal mandibular positions. The treatment was performed in three phases. In the first phase the upper incisors were proclined, and the deep bite was corrected with an upper removable plate. In the second phase the distal occlusion was corrected with an activator. The result was retained in the third phase with a second activator designed for retention. The relation between the retruded (RCP) and the intercuspal (ICP) mandibular positions was recorded with wax bites and dental casts mounted in a modified gnathothesiometer. The anteroposterior distance between RCP and ICP was large before the start of the treatment. The distance was unchanged after proclination of the upper incisors and correction of the deep bite but decreased after correction of the distal occlusion and increased again somewhat during the retention phase. The proclination of the upper incisors and the correction of the deep bite (phase one of the treatment) did not result in mandibular anterior positioning. This fact and the results of the recordings of the relation between RCP and ICP were interpreted as evidence that the mandible is not posteriorly displaced in Class II, Division 2 malocclusion.

Activator Appliances↗
PubMed1992

No posterior mandibular displacement in Angle Class II, division 2 malocclusion as revealed with electromyography and sirognathography.

The activity of the anterior and posterior temporal, and of the masseter muscles was studied by electromyography and the position of the mandible by sirognathography. The recordings were made in 22 children, aged 8-13 years, with Angle Class II, division 2 malocclusion before and during treatment of their malocclusion. The treatment comprised two phases: proclination of the upper incisors and bite raising with a removable plate, and the subsequent correction of the distal occlusion with an activator. The aim of the study was to reveal signs of anterior mandibular positioning during the treatment. The electromyographic recordings were made in the rest position of the mandible, and during maximal biting, chewing, and swallowing. The sirognathographic recordings comprised the positions of the mandible at rest, at intercuspation, and during tooth contact during chewing and maximal mandibular movements. The muscle activity at rest was unchanged during the period of observation. The activity during maximal biting, chewing, and swallowing decreased during the phase of proclination, which was interpreted as a result of occlusal instability. The positions of the mandible at rest, at intercuspation, and during chewing were stable during the treatment. Neither the electromyographic recordings nor the recordings of mandibular positions revealed any signs of anterior mandibular positioning during the treatment of the Class II, division 2 malocclusion.

Child↗
PubMed1992

Further studies of the pressure from the tongue on the teeth in young adults.

The pressures from the tongue on the teeth were recorded simultaneously in four locations lingual to the upper and lower central incisors, and left first molars in 20 young adults with largely normal occlusion. Measurements in the rest position, and during chewing and swallowing were made with an extra-oral pressure transducer incorporated in a fluid-filled system with intra-oral mouthpieces. The size of the dental arches was determined from dental casts. The median pressures in the rest position were low and negative at the upper incisors. Negative pressures at rest were recorded in a few subjects at all four points of measurement, most frequently at the upper incisors and least frequently at the lower molar. The pressures during swallowing were 2-4 times greater than those during chewing. There were no significant correlations between the pressures found and those recorded in the same individuals at an examination 2 years earlier. Positive correlations were found between the pressures recorded in the four locations during the various functions. This was interpreted as being an effect of the size of the tongue. The relatively few correlations between the pressures and the parameters describing the dental arch size indicated an adaptive role of the tongue within the confines of the dental arches.

Adult↗
PubMed1991

Temporal muscle activity during the first year of Class II, division 1 malocclusion treatment with an activator.

The activity of the anterior and posterior temporal muscles in response to treatment with a splint type of activator was studied in children with distal occlusion. The effect on muscle activity was compared with that in a similar group of children being treated with a headgear and with that in a control group receiving orthodontic treatment for Class I malocclusion. Electromyographic recordings were made with the mandible in the rest position and, during maximal bite, in the intercuspal position. The recordings were made before the start of the treatment and on three later occasions at 4-month intervals. The activity in the rest position was constant during the 1-year period of observation. During maximal bite the activity of the posterior temporal muscle decreased significantly in the group with headgear and the control group and in a subgroup of children with large protrusions in the construction bite who had been treated with activators. This decrease was considered to be an effect of occlusal instability brought about by the treatment. There was no evidence of a decrease in the postural (rest) activity of the posterior temporal muscle, although such a decrease has been described as a sign of forward displacement of the mandible during treatment with a functional appliance.

Activator Appliances↗
PubMed1991

Pressure from the tongue on the teeth in young adults.

Pressure from the tongue on the teeth was measured at the upper and lower central incisors and left first molars in 25 young adults with clinically normal occlusion. Repeated recordings with and without a period for accommodation to the intraoral measuring device, which was connected to an extraoral pressure transducer, were made in the rest position and during chewing and swallowing. Only minimal effects of accommodation were found. The system can thus be used without a period of adaptation before the actual test. The intraindividual pressure variations were of the same magnitude as for measurements of the pressure from the oro-facial soft tissues on the teeth recorded in earlier studies. The majority of the subjects had negative pressures at the upper and lower incisors and at the upper molar in the rest position. The pressures on the teeth during swallowing were comparatively great, while pressures during chewing were one-fourth to one-half of the swallowing pressures.

Adaptation, Physiological↗
PubMed1990

Effect of muscle exercise with an oral screen on lip function.

The study aimed at evaluating how training of the lips with an oral screen affects the strength of the lips and the pressure of the lips on the teeth. In addition, the effect of the treatment with an oral screen on the dentition was studied. The treatment and lip training programme was instituted for 9 months in 16 children, 7-11 years old, with protruding maxillary incisors. The effect on the dentition was studied on dental casts made before and at the end of the treatment, and 5 months thereafter, as well as on lateral cephalograms. The lip strength was recorded with a dynamometer. The pressure from the lips on the upper and lower central incisors at rest, and during chewing and swallowing was measured with an extra-oral pressure transducer incorporated in a water-filled system with an intra-oral measuring point. Measurements of lip strength and pressure were made regularly before and during the treatment, and continued for up to 10 months thereafter. The treatment resulted in a decrease of the overjet and upper dental arch length, but with some relapse after the treatment. The strength of the lips increased during the treatment, but decreased afterwards. The pressure from the lips on the teeth at rest and during swallowing was unaffected by the lip training. The pressure from the lower lip during chewing increased temporarily during the treatment period.

Cephalometry↗
PubMed1989

[Reproducibility of rhinomanometric measurements of nose breathing resistance and of x-ray cephalometric recordings of the natural head position in children].

The reproducibility of rhinomanometric recordings of nasal resistance to breathing and of cephalometric recordings of natural head position was studied in 30 children aged seven to 13 years. Posterior rhinomanometry, with and without decongestion of the nasal mucosa, was performed on two occasions. Rhinomanometric registration was possible in 92% of the children but the recorded values for air flow showed a considerable intraindividual variation. The natural standing position of the head and of the cervical spine as well as the relation between the head and the cervical spine was recorded in profile by X-ray cephalometry on two occasions. During the recording, the subject was looking at his face in a mirror. Systematic differences between the duplicate determinations and an accidental error of 4 degrees in the determination of the position of the head and the cervical spine were found. In about 10% of the cases, the differences between the duplicate determinations were greater than 10 degrees.

Airway Resistance↗
PubMed1989

Does the mandible alter its functional position during activator treatment?

The study aimed at revealing possible changes, in activator-free periods, in the positions and movements of the mandible induced by the wearing of an activator. Twenty-one children being treated with three different types of activator for the correction of Angle Class II, Division 1 malocclusion were studied. The movement capacity of the mandible, the rest position, and the position of tooth contact during chewing were recorded with a Sirognathograph before treatment and repeatedly during the first year of treatment. With the exception of a slight increase in the maximal protrusion, no changes in mandibular movement capacity were found. The anteroposterior position of the mandible in the rest position was constant during the period of treatment, but the freeway space increased. No changes in the position of the point of tooth contact during chewing were found. The study produced no evidence of a treatment-induced forward positioning of the mandible in activator-free periods.

Activator Appliances↗
PubMed1989

Lack of correlation between mouth-breathing and bite force.

The correlation between mouth-breathing and bite force was studied in 81 children, 7 to 16 years old. Mouth-breathing was diagnosed on the basis of the subject history, the rhinomanometrically determined nasal airflow and the size of the airway measured on the profile cephalogram. The maximum bite force was measured at the first molars. In addition, the facial morphology was analysed on profile cephalograms. Both mouth-breathing and bite force were associated with the facial morphology but there was no association between mouth-breathing and bite force. It was concluded that the long-face morphology characteristic of mouth-breathing children is not due to weak masticatory muscles.

Adolescent↗
PubMed1989

A comparison between anamnestic, rhinomanometric and radiological methods of diagnosing mouth-breathing.

Three methods of evaluating the mode of breathing were applied in 119 children aged 7-15 years who were to start orthodontic treatment for various malocclusions. The three methods were: the history, rhinomanometric recording of the nasal airflow and determination of the size of the airway on profile and frontal cephalograms. The variables describing the mode of breathing were correlated with the facial morphology and the natural position of the head and the cervical spine as recorded with profile cephalometry. There were no correlations between the results of the evaluation of the mode of breathing obtained with the three methods. Nor were there any correlations between these and the position of the head or the cervical spine. A history of mouth-breathing, the rhinomanometrically determined airflow through the nose and the size of the airway on the profile cephalogram were, however, correlated with the long face morphology characteristic of mouth-breathing. A diagnosis of mouth-breathing should be based on different supplementary methods, the history and the size of the airway on the profile cephalogram being at least as valuable as the rhinomanometric recordina.

Adolescent↗
PubMed1988

Cheek pressure and head posture.

Maxillary cheek pressures are measured in the molar area, at the teeth and high in the buccal sulcus, in both natural and extended head positions, with teeth at rest and in function. Highest pressures are found on the alveolar process, with some increases with the head extended and the jaw at dental rest position.

Adult↗