Abnormal palatopharyngeal muscle morphology in sleep-disordered breathing

The aim of the present study was to investigate whether histopathological changes can be detected in two soft palate muscles, the palatopharyngeus and the uvula, in 11 patients with long duration of sleep-disordered breathing (SDB). Muscle samples were collected froth patients undergoing uvulo-palatopharyngoplasty (UPPP). Reference samples from the corresponding areas were obtained at autopsy froth five previously healthy subjects. Muscle morphology, fibre type and myosin heavy chain (MyHC) compositions were analysed with enzyme-histochemical, immunohistochemical and biochemical techniques. The muscle samples from the patients, and especially those from the palatopharyngeus, showed several morphological abnormalities. The most striking findings were (i) increased amount of connective tissue, (ii) abnormal variability in fibre size, (iii) increased proportion of small-sized fibres, (iv) alterations in fibre type and MyHC compositions, (v) increased frequency of fibres containing developmental MyHC isoforms. Our findings point towards a pathological process of denervation and degeneration in the patient samples. Conclusively. the morphological abnormalities suggest a neuromuscular disorder of the soft palate in SDB patients. (C) 2002 Elsevier Science B.V. All rights reserved

Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supply

Four human soft palate muscles, and palatopharyngeus, the uvula, the levator and tensor veli palatini were examined using enzyme-histochemical, immunohistochemical and biochemical methods and compared with human limb and facial muscles. Our results showed that each palate muscle had a distinct morphological identity and that they generally shared more similarities with facial than limb muscles. The palatopharyngeus and uvula muscles contained 2 of the highest proportions of type II fibres ever reported for human muscles. In contrast, the levator and tensor veli palatini muscles contained predominantly type I fibres. A fetal myosin heavy chain isoform (MyHC), not usually found in normal adult limb muscles, was present in a small number of fibres in all palate muscles. The mean muscle fibre diameter was smaller than in limb muscles and the individual and intramuscular variability in diameter and shape was considerable. All palate muscles had a high capillary density and an unusually high mitochondrial enzyme activity in the type II fibres, in comparison with limb muscles. No ordinary muscle spindles were observed. The fibre type and MyHC composition indicate that the palatopharyngeus and uvula muscles are functionally involved in quick movements whereas the levator and tensor veli palatini muscles perform slower and more continuous contractions. The high aerobic capacity and the rich capillarisation suggest that the palate muscles are relatively fatigue resistant. Absence of ordinary muscle spindles indicates a special proprioceptive control system. The special morphology of the palate muscles may be partly related to the unique anatomy with only one skeletal insertion, a feature consistent with muscle work at low load and tension and which may influence the cytoarchitecture of these muscles. Other important factors determining the special morphological characteristics might be specific functional requirements, distinct embryological origin and phylogenetic factors

Soft tissue profile changes after vertical ramus osteotomy

Patients with mandibular prognathism have, for a number of years, been treated by orthognathic surgery and post-surgical changes in the facial profile have been widely reported. However, little is known about the influence of gender and age on the soft tissues. The aim of this study was to investigate changes in the soft tissue profile following orthognathic surgery and to evaluate gender and age differences in the ratios of soft-to-hard tissue change. Forty-two Caucasian adults (18 males and 24 females) aged from 17 to 46 years with mandibular prognathism who underwent vertical ramus osteotomy were included. Lateral cephalograms were taken 2-8 months pre- (T1) and 12-19 months post- (T2) surgically. Five skeletal, two dental, and seven soft tissue parameters were hand traced. Paired and unpaired Student's t-tests, Pearson's correlation coefficients, and multiple regression analyses were used to evaluate the data. Due to the setback of the mandible, soft and hard tissues changed in a 1:1 ratio at the mentolabial fold and chin in females and 1:1,1 in males. Significant differences of soft-to-hard tissue ratios were found at points Pg (P < 0.05) and Gn (P < 0.01). Age effects on the ratios were not significant. Other effects of the mandibular setback on the soft tissue profile were a significant increase in facial convexity, a deepening of the mentolabial fold, an increase in lower lip thickness, and a decrease in upper lip thickness, which increased the nasolabial angle. These findings indicate that use of gender-specific ratios in treatment planning might improve the accuracy of predicting treatment result

Fluoride varnish for the prevention of white spot lesions during orthodontic treatment with fixed appliances : a randomized controlled trial

BACKGROUND: Self-applied and professional fluorides are key elements to limit caries-related side-effects during orthodontic treatment with fixed appliances. OBJECTIVE: To evaluate the effectiveness of a new fluoride varnish formula containing 1.5% ammonium fluoride in preventing white spot lesions (WSLs) in adolescents undergoing multi-bracket orthodontic treatment. SUBJECTS AND METHODS: The study employed a randomized controlled triple-blinded design with two parallel arms. One hundred eighty-two healthy adolescents (12-18 years) referred to three orthodontic specialist clinics were eligible and consecutively enrolled. Informed consent was obtained from 166 patients and they were randomly allocated to a test or a placebo group (with aid of a computer program, generating sequence numbers in blocks of 15). In the test group, fluoride varnish was applied in a thin layer around the bracket base every sixth week during the orthodontic treatment, while patients in the placebo group received a varnish without fluoride. The intervention started at onset of the fixed appliances and continued until debonding. The endpoint was prevalence and severity of WSLs on the labial surfaces of the maxillary incisors, canines, and premolars as scored from high-resolution pre- and post-treatment digital photos with aid of a four-level score. RESULTS: One hundred forty-eight patients completed the trial, 75 in the test group and 73 in the placebo group (dropout rate 10.8%). The total prevalence of WSL's on subject level after debonding was 41.8% in the test group and 43.8% in the placebo group. The number of patients exhibiting more severe lesions (score 3 + 4) was higher in the placebo group (P < 0.05); the absolute risk reduction was 14% and the number needed to treat was 7.1. LIMITATIONS: The multicentre design with somewhat diverging routines at the different clinics may have increased risk for performance bias. No health-economic evaluation was carried out. CONCLUSIONS: Regular applications of an ammonium fluoride varnish reduced the prevalence of advanced WSL during treatment with fixed orthodontic appliances. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT03725020). PROTOCOL: The protocol was not published before trial commencement

von Langenbeck procedures at 8 months or Wardill at 18 months for primary repair of cleft palate in adult Swedish patients with unilateral complete cleft lip and palate: A study of facial growth.

The purpose of this study was to compare facial growth in patients with unilateral complete cleft lip and palate (UCLP) in whom the palate was repaired with the von Langenbeck procedure at 8 months (L-8), or the Wardill procedure at 18 months (W-18). A total of 151 unaffected subjects were used as a reference series. Sixty-one adult patients, 34 in the L-8 group and 27 in the W-18 group, were investigated clinically and with lateral skull radiography and also filled out a questionnaire about their dental condition. Multiple linear regression was used to analyse the effects of the surgical strategy, sex, and the presence of a velopharyngeal flap on several dependent variables indicating sagittal jaw relations, vertical jaw relations, and inclination of incisors. The UCLP group was characterised by a short (n-sp) and retrusive maxilla (s-n-ss) and a retrusive mandible for women (s-n-sm), larger maxillary inclination (NSL/NL), more retroclined lower incisors (IL(I)/ML), shorter upper facial heights (n-sp) and normal total face height (n-gn) than the reference group. In the UCLP group there were significant differences between men and women in mandibular prognathism (s-n-sm), maxillary/mandibular relations (ss-n-sm), maxillary inclination (NSL/NL), total anterior facial height (n-gn), and upper anterior facial height (n-sp). Lateral crossbite was found in 20% of the UCLP group. The prevalence was similar in the L-8 and W-18 groups. Almost 80% of the patients in the UCLP group considered that their dental condition was good. The choice of surgical strategy had no significant influence on the variables measured on facial morphology

von Langenbeck procedures at 14 months or Wardill at 18 months for primary repair of cleft palate in adult Swedish patients with bilateral complete cleft lip and palate: A study of facial growth.

We compared facial growth in patients with bilateral complete cleft lip and palate (BCLP) in whom the palate had been repaired by the von Langenbeck procedure at the age of 14 months (L-14), or by the Wardill procedure at 18 months (W-18). A total of 151 unaffected subjects were used as a reference group. Thirty-six adult patients, 26 in the L-14 group, and 10 in the W-18 group, were investigated clinically and with lateral skull radiography, and they also filled out a questionnaire about their dental condition. Multiple linear regression was used to analyse the effect of surgical strategy, sex, and the presence of a velopharyngeal flap on several dependent variables indicating sagittal and vertical jaw relations, and inclination of incisors. The BCLP group was characterised by a pre-normal basal relation (ss-n-sm), retroclined upper (ILs/NL) and lower (ILi/ML) incisors, maxillary retrognathism (s-n-ss) in men, larger maxillary plane angle (NSL/NL) in women, larger mandibular plane (NSL/ML) and intermaxillary vertical relation (NL/ML) in men, and smaller anterior facial height (n-gn) and upper anterior facial height (n-sp). In the BCLP group, differences in outcomes could be explained only by sex. The sagittal jaw base relation (ss-n-sm) was significantly smaller in men than in women, whereas the total anterior facial height (n-gn) was greater in men. Lateral crossbite was found in about 75% of patients. About 70% were satisfied with their dental condition. The choice of surgical strategy had no significant influence on the variables measured on facial morphology