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Biomedical subjects

M Ringqvist

Publications and source records attributed to M Ringqvist.

At least 19 recordsLinked to original sources
PubMed1999

A prospective randomized study of a dental appliance compared with uvulopalatopharyngoplasty in the treatment of obstructive sleep apnoea.

The enthusiasm for uvulopalatopharyngoplasty (UPPP) in the treatment of obstructive sleep apnoea (OSA) has declined in recent years, partly because of a lower success rate over time and partly because of adverse effects. Reports on the beneficial effects of dental appliances exist, but only one prospective randomized study has been published comparing dental appliances with nasal continuous positive airway pressure (CPAP) treatment. No study has been published comparing dental appliance treatment with UPPP. Ninety-five male patients with confirmed OSA, subjective daytime sleepiness and an apnoea index (AI) > 5 were randomized for subsequent treatment with either a dental appliance or UPPP. There were 49 patients in the dental appliance group and 46 in the UPPP group. Thirty-seven patients in the dental appliance group and 43 in the UPPP group completed the 12-month follow-up. The success rate (rate of patients with at least a 50% reduction in AI) for the dental appliance group was 95%, which was significantly higher (p < 0.01) than the 70% success rate for the UPPP group. According to the criteria for OSA (apnoea index > or = 5 or apnoea/hypopnoea index > or = 10), 78% of the dental appliance group and 51% of the UPPP group were normalized after 12 months. The difference between the groups was significant (p < 0.05). These findings suggest that the dental appliance technique is useful in the treatment of mild to moderate OSA.

Humans↗
PubMed1998

Anterior-inferior mandibular osteotomy in treatment of obstructive sleep apnea syndrome.

In a prospective randomized study on treatment of obstructive sleep apnea syndrome, anterior-inferior mandibular osteotomy with the purpose of stretching the suprahyoidal muscle was performed as one of the treatment methods. Ten men aged 20 to 65 years, without cardiovascular or neurologic disease, with normal maxillomandibular relation, and having an apnea index between 5 and 25 were included in the study. After a specially designed osteotomy of the chin, the anterior suprahyoidal muscles were detached, stretched approximately 10 to 12 mm, and sutured. The chin was then placed in its original position and post-operative evaluation was performed. Although there were initial reports of decreased daytime sleepiness and less snoring after surgery, the results after 12 months were discouraging. Somnographic registration (apnea index, apnea/hypopnea index, and oxygen desaturation index) as well as cephalometric analysis failed to show positive results. Hence, suspension of the suprahyoidal muscles as a method of treatment for obstructive sleep apnea syndrome cannot be recommended.

Adult↗
PubMed1990

Posterior repositioning of the entire maxilla without postoperative intermaxillary fixation. A clinical and cephalometric study.

In 30 patients posterior repositioning of the entire maxilla has been performed. No postoperative intermaxillary fixation (IMF) has been applied. The surgical procedure is described and data given on the distance of repositioning. Results of cephalometric analysis indicate good long-term stability after surgery. We concluded that omitting IMF not only enhances patient comfort, but has no deleterious effect on postoperative stability of the maxilla.

Adolescent↗
PubMed1989

Sagittal split osteotomy of the mandible without postoperative intermaxillary fixation. A clinical and cephalometric study.

A modified sagittal split technique has been evaluated in 42 dentate patients, in whom no postoperative intermaxillary fixation was used. Twenty-three patients had mandible set-back performed and 19 patients mandibular advancement. The method makes possible a safe split osteotomy under controlled conditions. The design of the osteotomy and screw osteosynthesis counteracts relapse. Omitting intermaxillary fixation facilitates postoperative handling of the patient and promotes rehabilitation.

Adolescent↗
PubMed1989

Maxillary osteotomies without postoperative intermaxillary fixation (anterior, superior and inferior repositioning of entire maxilla). A clinical and cephalometric study.

Surgical correction of maxillary anomalies with anterior-superior or anterior-inferior repositioning of the segment was performed in 50 patients. The maxillary segment was stabilized by means of steel wires as horizontal mattress sutures, which, in all cases, gave very good primary stability. In case of insufficient bone contact miniplates were used. Postoperatively no rigid intermaxillary fixation (IMF) was applied. There are several advantages to not using intermaxillary fixation: 1) It is possible to carry out immediate postoperative inspection of the location of the condyles and thereby confirm that the segments are in the expected position. 2) Segment fixation is not disturbed by mandibular movements during recovery from general anaesthesia. 3) Manipulations by the anaesthesiologist immediately after surgery are not interfered with. 4) For the patient there is better postoperative comfort with no breathing, talking or feeding problems. 5) Minor corrections of intercuspation by means of orthodontic elastics are possible. These can act in the required direction and will not disturb the masticatory function. Masticatory function was resumed immediately after surgery and was usually normalized within 2-3 weeks. Cephalometric analysis revealed no significant relapse subsequent to surgery. Thus we conclude that omitting IMF, among other advantages, enhances patient comfort and has no negative effect on the postoperative stability of the maxilla.

Adolescent↗
PubMed1988

Simultaneous correction of maxillary and mandibular dentofacial deformities without the use of postoperative intermaxillary fixation. A clinical and cephalometric study.

Simultaneous correction of maxillary and mandibular anomalies was performed in 23 patients. The maxillary segment was stabilized by means of steel wires as horizontal mattress sutures, which, in all cases, gave good stability. A modified sagittal split has been applied in all cases. The method makes a safe split osteotomy possible under controlled conditions. The design of the osteotomy and the screw osteosynthesis counteract relapse. Postoperatively, no rigid intermaxillary fixation (IMF) was used. Masticatory function was started from the 1st postoperative day and in most cases was normalized 2-3 weeks after surgery according to the patients own judgement. Cephalometric analysis was performed on 15 patients by a superimposition technique. There was an overall good postoperative stability of the maxilla and mandible in the horizontal and vertical planes. We conclude that omitting IMF has no negative effect on the postoperative stability of the fragments.

Adolescent↗
PubMed1985

Fiber type composition of monkey forearm muscle.

Histochemical staining methods were applied to selected superficial forearm muscles of Macaca mulatta monkeys. The muscles were analyzed with regard to relative percentage distribution of different fiber types. In extensor carpi radialis brevis, extensor carpi radialis longus, and palmaris longus there was an even dispersion of each fiber type from the superficial to the deep part of the muscle. Extensor digiti communis showed a slightly higher percentage of type I fibers and correspondingly lower percentage of type II fibers in its central as compared to its superficial area. Three muscles, bracioradialis, extensor carpi ulnaris, and flexor carpi radialis, displayed marked differences between their superficial and deep areas. All of them contained a higher proportion of type I fibers (and correspondingly lower percentage of type II fibers) in their deep parts than in their superficial areas. Flexor carpi ulnaris (FCU) differed from the other muscles studied in that it showed distinctly different fiber proportions on either side of a central tendon. While the ulnar head of FCU was dominated by type II fibers (71% compared to 27% type I fibers), the humeral head contained a larger proportion of type I fibers (58% vs. 40% type II fibers). This difference in fiber type distribution suggests different functional demands for the two heads of FCU, with the possibility of more sustained activity in the humeral head.

Animals↗
PubMed1984

Heterogeneous distribution of myosin in human masticatory muscle fibres as shown by immunocytochemistry.

On the basis of enzymic properties, different fibre types can be distinguished in human skeletal muscle (type I fibres and type II fibres with subtypes) and there is a correlation between fibre types and the occurrence of slow and fast myosin. In human masticatory muscles, fibres with ATPase activity at pH 9.4, intermediate between that of type I (low activity) and type II (high activity), are frequent. On cryostat-sectioned material, highly specific antibodies against fast myosin, slow myosin and slow light chains were applied. The myosin composition of human masticatory muscles was very heterogeneous, in contrast to that in limb muscles, with various proportions of slow and fast myosins, heavy as well as light chains. Type I fibres contained slow myosin only and type II mainly fast myosin, ATPase IM and type IIC fibres contained a mixture of slow and fast myosins in variable amounts. The findings conform with physiological evidence of a continuum of contraction times for motor units in the human masticatory muscles and suggests that these muscles are highly adapted to the special and complicated functions of the stomatognathic system.

Adenosine Triphosphatases↗
PubMed1984

Development of fiber types in human fetal muscle. An immunocytochemical study.

Human fetal muscles have been studied using immunocytochemical methods with antibodies directed against different myosin isoforms. We show that fiber type differences can be detected as early as 15-16 weeks of gestation. At this time it would appear that both the heavy and light chains characteristic of slow myosin are found in some myotubes.

Adenosine Triphosphatases↗
PubMed1982

Histochemical fibre composition of the human digastric muscle.

The histochemical muscle-fibre composition of the anterior and posterior belly of the human digastric muscle was analysed in young male adults. Both bellies, of differing embryological origin and supplied by different cranial nerves, showed a fibre composition similar to that of normal limb and trunk muscles. Type I, type IIA and type IIB fibres each occupied about one-third of the total fibre population and were evenly distributed in a mosaic pattern. About 1 per cent of fibres were type IIC and ATPase (pH 9.4) intermediate fibres. Thus, there were major differences between the anterior belly of digastric and the likewise trigeminal nerve innervated masticatory muscles with respect to both histochemical profile and size and distribution of various types of fibre. The observations suggest that the fibre pattern of the digastric is not primarily related to its specific nervous supply but its special functional demands. The predominance of type II fibres indicates a capacity for fast acceleration and speed in mandibular movements. The disparity in fibre-type profile between the digastric and the jaw elevator muscles might be related to changing demands during evolution. Civilized diets need no heavy mastication and, while the requirements upon the jaw elevators have thus changed, the functional demands on the jaw openers would have remained unchanged.

Adenosine Triphosphatases↗
PubMed1982

Histochemical fibre-type profile in the human masseter muscle.

A histochemical characterization of the masseter muscle was performed on biopsy samples of dentate subjects with normal occlusion. There was a continuum of ranges of oxidative and glycolytic capacities of the masseter muscle fibres. Besides the lightly-stained type I and the darkly-stained type II fibres, fibres with intermediate staining reactions for standard ATPase at pH 9.4, IM fibres, were seen in all biopsy samples. IM fibres had some staining characteristics in common with type I, i.e. the reaction for NADH-TR and for ATPase after preincubation at pH 4.6 and 4.2. Like type II fibres they showed strong reaction for menadione-linked alpha-glycerophosphate dehydrogenase and for phosphorylase. The ATPase reaction after preincubation at pH 4.6 did not generally reveal subtypes of type II. It is concluded that the masseter muscle in normal human subjects has a very special fibre composition, with ATPase-IM fibres being a part of the normal fibre population.

Adenosine Triphosphatases↗
PubMed1980

The reliability of histochemical fibre typing of human necropsy muscles.

The reliability of muscle fibre typing of post mortem specimens was investigated with special reference to the influence of time and temperature. In specimens stored at +4 degrees C, muscle fibre typing could be reliably performed up to at least ten and fifteen days post mortem for the masseter and biceps brachii muscles respectively. The corresponding figures for storage at room temperature were three and six days. The difference in the preservation of enzyme activity between masticatory and limb muscles might be related to the demonstrated difference in the fibre type composition and thus the enzyme content and energy sources.

Adenosine Triphosphatases↗
PubMed1977

Differentiation of fibres in human masseter, temporal and biceps brachii muscles. A histochemical study.

Masseter, temporal and biceps brachii muscles were histochemically evaluated for fibre type differentiation on 19 aborted fetuses (gestational ages 15-23 weeks), in 2 premature infants of 34 and 36 weeks gestation and in 2 fullterm stillborn infants. There was no convincing evidence of fibre type differentiation in the masticatory muscles before 22 weeks' gestation while a fairly distinct differentiation was seen in biceps brachii specimens at 16 weeks' gestation with ATPase at pH 4.35. Around 22 weeks two types of fibre were found in all specimens with ATPase at pH 4.35. With regular ATPase (pH 9.4) there was a relatively weak difference in staining between different types of fibre in the masticatory muscles. In biceps brachii Type I and Type II were demonstrated. Neonatally 3 levels of staining were seen in biceps brachii with regular ATPase (pH 9.4); while ATPase pH 4.35 and 4.6 demonstrated the subtypes IIB and IIC. In the masticatory mucles only 2 levels were recognized with regular ATPase and all type II fibres had the characteristics of Type IIC as seen with with ATPase at pH 4.35.

Adenosine Triphosphatases↗