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The palatal shape of upper removable appliances. Influence on the tongue position in swallowing.

In a clinical-experimental study the influence of variations in the palatal shape of upper removable appliances upon tongue position during swallowing was investigated. During a clinical examination of 35 dental students displaying a physiological swallowing pattern, the tongue position during swallowing was recorded by palatography on an individually adapted upper plate. During swallowing with a roughened plate with an individual palatal shape and an imitated palatal papilla, the tongue position was significantly more posterior than with a highly polished, unstructured plate. The number of students displaying a visceral swallowing pattern was significantly smaller with a roughened plate with palatal folds and papilla then with a polished, smooth appliance. A roughened, individually shaped appliance with palatal folds and palatal papilla should therefore be used after myofunctional therapy and in cases where disturbance of tongue function by the appliance is not desirable.

Adult↗

Cyclic AMP-dependent protein kinase in human embryonic palate mesenchymal cells.

Growth and differentiation of cells derived from the embryonic palate are critically dependent on the intracellular cAMP-mediated signal transduction pathway. Human embryonic palate mesenchymal (HEPM) cells have been widely used to examine the effect of teratogens on palatal tissue growth and differentiation, as well as a prescreen for environmental teratogens. This study examined responsiveness of HEPM cells to agents known to stimulate adenylate cyclase, characterized cAMP-dependent protein kinases (cAMP-dPK) (EC 2.7.1.37) and investigated to what extent HEPM cells reveal adaptational responses to cAMP at the level of cAMP-dependent protein kinase. HEPM cells exhibited a total cell cycle transit time of approximately 22 h and responded maximally, when confluent, to prostacyclin (PGI2), prostaglandin E2 (PGE2), and isoproterenol with time- and dose-dependent increases in intracellular levels of cAMP. The order of sensitivity to hormonal activation of adenylate cyclase was PGE2 > isoproterenol > PGI2. Basal cAMP-dependent protein kinases activity was 0.184 fmol phosphate transferred from ATP to histone per microgram protein per minute under conditions where endogenous phosphatases did not significantly affect protein phosphorylation. Regulatory subunits of cAMP-dPK in HEPM cells were characterized by the binding of [3H]cAMP to cytosolic fractions. Specific binding was saturable at approximately 50 nM indicating the presence of binding sites that are finite in number. Calculation of half-maximal binding yielded an estimated Kd of 25 nM indicating the presence of high affinity binding sites. Cyclic AMP-dPK regulatory subunits were also photoaffinity labeled with 8-N3-[32P]-cAMP, subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and radiolabeled bands visualized by autoradiography. Photoactivated incorporation of 8-N3-[32P]cAMP was detected into two proteins of molecular weight (M(r)) 45,000 and M(r) 51,000 representing, respectively, the RI alpha and RII beta subunits of cAMP-dPK. Binding of [32P]8-azido cAMP to proteins of M(r) 45,000 (RI alpha) and M(r) 51,000 (RII beta) was increased in response to elevation of intracellular cAMP via inhibition of its breakdown with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, or by direct activation of adenylate cyclase with forskolin. HEPM cells thus revealed adaptational responses to cAMP at the level of cAMP-dependent protein kinase. Characterization of the cAMP signal transduction pathway in HEPM cells, derived from embryonic palatal tissue which is critically dependent on this pathway for normal development, may provide information fundamental to a clear understanding of cellular events involved in palatal ontogeny. These results highlight several important differences between HEPM cells and murine embryonic palate mesenchymal cells.(ABSTRACT TRUNCATED AT 400 WORDS)

1-Methyl-3-isobutylxanthine↗

Regulation of TGF beta 3 gene expression in embryonic palatal tissue.

The TGF beta family of genes has been shown to play an important role in regulating various aspects of development, although the mechanisms by which TGF beta exerts its effects have not yet been clarified. Growth and differentiation of both murine embryonic palate mesenchymal (MEPM) cells and palatal epithelium can be regulated by the TGF beta s. We therefore examined the expression of mRNAs encoding TGF beta 1, TGF beta 2, and TGF beta 3 in developing embryonic palatal tissue as well as factors that modulate their levels of expression. Northern blot analysis of RNA isolated from murine embryonic palatal tissue on gestational days (GD) 12, 13, and 14 demonstrated the presence of one mRNA transcript for TGF beta 1 (2.5 kb), two transcripts for TGF beta 2 (4.4 kb, 6.0 kb), and one transcript for TGF beta 3 (3.5 kb). Although steady-state levels of TGF beta 1 mRNA showed no changes during development of the palate, TGF beta 2 mRNA levels were maximal on both GD13 and GD14 and TGF beta 3 mRNA levels transiently increased on GD 13. In addition, levels of TGF beta 3 mRNA seemed much higher than either TGF beta 1 or TGF beta 2. both TGF beta 1 and TGF beta 2 were able to increase, in a dose-related manner, the expression of TGF beta 3 mRNA in murine embryonic palate mesenchymal cells in vitro. In contrast, epidermal growth factor (EGF) down-regulated the expression of TGF beta 3 mRNA even in the presence of TGF beta 1 or TGF beta 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Development and biomechanical investigation of a new compound palatal arch.

BACKGROUND AND AIM: There are many advantages in using a transpalatal arch in orthodontic treatment. In addition to the active movement of individual teeth, such an arch can be used to provide additional anchorage. The aim of this study was to further develop and improve both the clinical and the biomechanical properties of the conventional transpalatal arch. MATERIAL AND METHODS: Currently available compound material components form an established part of orthodontic therapy. The Compound palatal arch broadens the scope of this treatment system. The biomechanical effects of the newly developed Compound palatal arch were verified by comparing them with those of commercially available conventional transpalatal arches. The recently developed Compound palatal arch is made of one compound element: nickel-titanium/stainless steel. The specific dimensions and design of the nickel-titanium element are aimed at exploiting its superelasticity, even during active molar movement. The biomechanical investigation was carried out using six-component measuring sensors to register the forces and moments in the three spatial dimensions (x, y and z) at 37 degrees C. The following appliances were investigated: Goshgarian transpalatal arch, quad-helix appliance, Arndt memory expander, and Compound palatal arch. RESULTS: Transpalatal arches could not be inserted without the arch being under tension. This is particularly important when the arch is being used for anchorage purposes. The Goshgarian arch had to be classified as problematic for the movement of single teeth as the load/deflection rate was high. However, this can be utilized for anchorage purposes. The clinical advantage of a quad-helix appliance is the option for asymmetric tooth movement. CONCLUSIONS: This study showed that the quad-helix was effective for both unilateral and bilateral derotation as well as for transversal tooth movement. However, expansions should be confined to < or = 4 mm, and derotations to < 10 degrees, as forces and moments are otherwise not within the physiologic range. The Arndt memory expander displayed no advantages over either the quad-helix appliance or the Goshgarian transpalatal arch. Nor did it display any superelastic properties. The linear relationship, the relatively high forces and moments, and the lack of clinical adjustability cast doubts on the benefits of this appliance. The newly developed Compound palatal arch showed substantial advantages in molar derotation compared with conventional transpalatal arches. Superelastic properties were achieved through the design and positioning of the nickel-titanium element. Expansion with the Compound palatal arch was comparable with that with conventional transpalatal arches. The clinical advantage is in the fact that this appliance can be reactivated and that dental asymmetries can be treated.

Activator Appliances↗

Development of a suspension organ culture of the fetal rat palate.

On the basis of an already established suspension organ culture system of mouse palate anlagen, we developed a corresponding culture system for rat palate anlagen. In order to optimize the culture results we systematically studied the influence of main "culture conditions" such as dissection technique, rotation speed, gassing schedule, and developmental stage at the onset of culture for mice and rat palate anlagen. This system allows culturing rat palate anlagen from day 15 of gestation to day 18 + 8 h (80 h) under serum- and antibiotic-free conditions using a chemically defined medium, resulting in 90% fused palates. The explants, containing the maxillary vault and the palatal shelves, were cultured in siliconized culture flasks at a rotation speed of 12 rpm and a temperature of 37 degrees C (Table 1).

Animals↗

Botulinum toxin is effective and safe for palatal tremor: a report of five cases and a review of the literature.

Palatal tremor (formerly palatal myoclonus) is an extremely rare, but potentially treatable cause, of objective tinnitus. The tinnitus is thought to be secondary to rhythmic involuntary movements of the soft palate. Its aetiology is variable and it remains difficult to treat. Many different medical and surgical remedies have been tried but none have demonstrated reproducible success. Botulinum toxin has been used in sporadic cases and seems to produce good results. Ten patients with palatal tremor have presented to this department over the last three years. After discussion with the patients with regard to the management of this condition and possible complications, five opted for botulinum toxin therapy and five declined further intervention. Clinical diagnosis was made on the confirmation of soft palate movements synchronous with an audible clicking noise. Five patients underwent botulinum toxin injection into the insertion of the levator and tensor veli palatini muscles. Of the five that were treated with toxin, four showed complete resolution of symptoms after a course of treatment. Only one patient reported transient side effects. This would suggest that botulinum toxin is a safe and effective first line treatment for palatal tremor.

Botulinum Toxins, Type A↗

Soft palate movement during sucking behavior.

To clarify the aspects and role of oropharyngeal closure, soft palate movements during sucking were observed and then assessed by electromyographic and fluoroscopic analyses. Three patterns of sucking movements by the palatoglossus and levator veli palatini muscles were analyzed with electromyographic means in seven healthy adults. Furthermore, a forced sucking maneuver, which required special effort to produce a strong sucking pressure by opening the jaw, was analyzed using lateral fluoroscopy in three of the subjects. During all tested sucking movements, the palatoglossus muscle showed continuous activity. The levator veli palatini muscle did not show remarkable activity during regular air sucking or water sucking when water was held in the oral cavity. However, its participation increased when intraoral sucking pressure was increased by opening the jaw, and lateral fluoroscopic examinations revealed that the soft palate was pulled toward the oral cavity to form a tight contact between the rostral portion of the soft palate and the retrotongue, causing the soft palate to make an "L" shape. The palatoglossus muscle plays a major role in palatal movement during sucking. Furthermore, the levator veli palatini muscle, whose activity was observed only during high-pressure sucking with an open jaw, may act to maintain tension in the soft palate against strong negative pressure in the oral cavity.

Adult↗

Cross-talk between signaling pathways in murine embryonic palate cells: effect of TGF beta and cAMP on EGF-induced DNA synthesis.

Signaling pathways utilized by EGF, cAMP, and TGF beta have been demonstrated to play critical roles in normal palate development. Stimulation of these pathways has been shown in palate cells and numerous other systems to affect cell growth. Because proper regulation of cell growth is critical to palate development, we speculate that fine regulation of palatal cell growth may be accomplished through crosstalk between these signaling pathways. We therefore set out to determine the effects of cAMP and TGF beta on EGF-induced cell proliferation in murine embryonic palate cells. We found that both TGF beta and cAMP inhibited the proliferative response of cells to treatment with EGF, whereas H89, a serine/ threonine protein kinase inhibitor with selectivity towards cAMP-dependent protein kinase, increased the cells' proliferative response to EGF. Genestein, a selective inhibitor of tyrosine kinases, at high doses abrogated the cells' proliferative response to EGF, confirming that EGF's ability to induce cell proliferation is critically dependent upon tyrosine kinase activity. Lower doses of genestein, however, actually enhanced cellular response to EGF. The data suggest that both the TGF beta- and cAMP-mediated signaling pathways may be involved in modulation of the effects of EGF on palate cell growth in vivo.

Animals↗

The effect on the ear of late closure of the cleft hard palate.

Thirty-three patients with cleft palate are reviewed. The late effects on the ear of delayed closure of the hard palate after early soft palate repair are compared with the results of simultaneous early closure of both hard and soft palate clefts. Delayed closure of the hard palate does not affect the incidence of otitis media, the number of insertions of ventilation tubes or the findings on otoscopy. The prevalence of sensorineural hearing loss is significantly raised by late closure of the hard palate. The reason for this is unknown.

Adolescent↗

Epidermal growth factor potentiates the induction of ornithine decarboxylase activity by prostaglandins in embryonic palate mesenchymal cells: effects on cell proliferation and glycosaminoglycan synthesis.

Epidermal growth factor (EGF) and prostaglandins (PGs) have been implicated in the regulation of a number of developmental processes in the mammalian embryonic palate. Normal palatal ontogenesis is dependent on the presence and quite possibly on the interaction of various hormones and growth factors. The interaction between EGF and PGs in regulation of murine embryonic palate mesenchymal (MEPM) cell growth and differentiation was therefore investigated by monitoring the activity of ornithine decarboxylase (ODC), the principle and rate limiting enzyme of polyamine biosynthesis. ODC activity is tightly coupled to the proliferative and differentiative state of eukaryotic cells and therefore serves as a reliable indicator of such cellular functions. Treatment of confluent cultures of MEPM cells with EGF (1-50 ng/ml) resulted in a dose-related increase in ODC activity, while similar treatment with either PGE2 or PGF2 alpha (at concentrations up to 1 microM) did not elicit a dose-dependent increase in enzyme activity. Concurrent treatment of MEPM cells with EGF (20 ng/ml) and either PGE2 or PGF2 alpha (0.1-10000 nM) resulted in a marked prostaglandin dose-dependent induction of ODC activity, suggesting a strong cooperative interaction between these factors. ODC activity was maximal by 4 to 8 hr and could be completely inhibited by preincubation of the cells with actinomycin D or cycloheximide, indicating that de novo synthesis of RNA and protein is necessary for enzyme induction. Stimulation of ODC activity by EGF and PGE2 in these cells was not positively correlated with the level of cellular DNA synthesis but did result in a ninefold increase in the synthesis of extracellular glycosaminoglycans (GAGs), a key macromolecular family implicated in palatal morphogenesis. Stimulation of GAG synthesis was significantly inhibited by the administration of 5 mM DFMO (an irreversible inhibitor of ODC), indicating that the marked increase in GAG production was dependent, in part, on the induction of ODC activity by EGF and PGE2. Qualitative analysis of the palatal GAGs indicated that synthesis of several major classes of GAGs was stimulated. Collectively these data demonstrate a cooperative interaction between EGF and PGs in the induction of ODC activity. Such activity may serve to regulate the synthesis of GAGs, which are instrumental in mammalian palatal ontogenesis.

Animals↗

Tissue and species specific responsiveness of developing avian and murine secondary palates to prostaglandin E2 stimulation.

The objective of this study was to determine the responsiveness of isolated embryonic murine and avian epithelial and mesenchymal tissue to PGE2 stimulation. On days 12 and 14 of gestation, murine palatal epithelium responded to PGE2 (10(-5) M) with 3.5 and 4.0 fold elevations in intracellular cAMP, respectively. On day 13 of gestation, murine palatal epithelium was responsive to forskolin, PGE1 and isoproterenol as indicated by the accumulation of cAMP, but unresponsive to PGE2 and PGF2 alpha less than treatment. Avian palatal epithelium and mesenchyme, developmental stages 31 to 34, as well as murine palatal mesenchyme on day 13 of gestation responded to PGE2 treatment with dose-dependent elevations in intracellular cAMP. Of importance, is the lack of responsiveness of murine palatal epithelium to PGE2 treatment on day 13 of gestation. This corresponds to the time of murine palatal medial edge epithelial differentiation. Lack of a PGE2 response may effect, initiate or occur as the result of murine medial edge epithelial differentiation.

Animals↗

The variation in appearance of the hard palate and the nasal floor in rotational panoramic radiography.

This study was performed to find the origin of the radiopacity in the region of the hard palate and to explain the variability in appearance of this radiopacity in panoramic radiographs. It could be demonstrated, with the use of metal markers attached to a dry human skull, that the radiopacities seen in the region of the hard palate represent the junction of the nasal septum and the hard palate and the junction of the maxillary sinus to the hard palate. The appearance of one or two lines depends on the angulation of the skull. A more inclined (chin-down) position of the skull produces two lines, whereas a chin-up position results in a superimposition of the two lines and produces only one line. The image of the junction of the bony septum and palate is unsharp because of the greater distance from the focal plane. The junction of the maxillary sinus to the hard palate is closer to the image layer and will appear as a sharp line.

Cranial Sutures↗

Development and ciliation of the palate in two frogs, Bombina and Xenopus; a comparative study.

The morphological changes that occur during metamorphosis in the palates of two types of anuran larvae (a discoglossid, Bombina orientalis, and a pipid, Xenopus laevis) are compared. In B. orientalis the structural changes are accompanied by the ciliation of the palate epithelium. Ciliation begins in the anterior region of the palate and continues in a posterior direction throughout metamorphosis. By contrast, the palate of X. laevis never becomes ciliated during its development. Instead, two ciliated grooves develop between the choanae (nasal openings) and the esophageal opening. The grooves transport mucus and trapped objects out of the internal nares and toward the esophagus. These grooves are compared to similar structures on the palate of adult B. orientalis. The timing and pattern of ciliogenesis during metamorphosis in each of these anurans is also described relative to well-established staging series for external frog development. We show that the onset and location of ciliogenesis are consistent and predictable in these anurans and, therefore, make the frog palate an excellent system for the study of ciliogenesis.

Animals↗

TCDD-induced altered expression of growth factors may have a role in producing cleft palate and enhancing the incidence of clefts after coadministration of retinoic acid and TCDD.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is teratogenic in mice, inducing cleft palate and hydronephrosis at doses which are not overtly maternally toxic or embryotoxic. After TCDD exposure the palatal shelves of normal size come into contact, but fail to fuse due to altered differentiation of the medial epithelial cells. These cells continue to express EGF receptors, proliferate, and differentiate into an oral-like stratified squamous epithelium. The present study examines the effect of TCDD on the expression of growth factors which are believed to regulate differentiation and proliferation in the palate. This study also examined the combined effect of TCDD and retinoic acid (RA), since in teratology studies coadministration of these agents results in an enhancement of cleft palate incidence. Embryos were exposed in vivo on Gestation Day (GD) 10 or 12 to TCDD ot TCDD + RA and the palatal shelves were dissected on GD 14-16. Growth factor expression was determined immunohistochemically using antibodies to TGF-alpha, EGF, TGF-beta 1, or TGF-beta 2. The growth factors displayed specific spatial and temporal expression in the palatal shelves. TCDD reduced the expression of TGF-alpha, EGF, and TGF-beta 1 in epithelial and mesenchymal cells. The degree of reduction was generally greater after exposure on GD 10 to TCDD alone or in combination with RA when compared to that on GD 12. The abnormal proliferation and differentiation of TCDD-exposed medial cells may be a response to reduced expression of EGF and TGF-alpha. Low levels of these factors may be related to the previously observed elevated levels of EGF receptors in medial cells. In other systems, low levels of ligand have resulted in upregulation of the EGF receptor. Continued proliferation and altered differentiation could also be attributable to decreased levels of TGF-beta 1, a factor inhibitory to epithelial proliferation. Since TGF-beta 1 stimulates mesenchymal growth and TGF-alpha and EGF stimulate epithelial proliferation, the formation of small shelves after exposure to TCDD + RA on GD 10 may be due to the severe reduction in these factors. Only a slight to moderate reduction in growth factor expression occurs after exposure to TCDD + RA on GD 12 and in this case shelves of normal size form. Since TCDD and RA appear to act in part through pathways that involve TGF-beta 1, in vitro experiments were designed to examine the involvement of TGF-beta 1 in TCDD teratogenicity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Growth of the maxilla after soft tissue palatal surgery at different ages in beagle dogs: a longitudinal radiographic study.

This study investigated maxillary growth after palatal surgery at different ages in beagle dogs. Soft tissue clefts were created in the median region of the palate at the age of 6 (group 1), 16 (group 2), and 25 weeks (group 3). Relaxation incisions were made, and the mucoperiosteum was elevated and closed in the midline, leaving two areas of denuded bone adjacent to the dentition. Metallic implants were placed in the palate, and dorso-ventral and lateral radiographs were made until the age of 37 weeks to study sutural growth and overall growth of the maxilla. In groups 1 and 2, growth in the midpalatal suture was less, compared to the control, from 16 to 25 weeks and from 16 to 37 weeks of age. In group 2, less increase was also found in the transverse palatal sutures. Group 3, the sham group, and the control group did not show significant differences. None of the dimensions measured on the lateral radiographs showed any significant differences for any group. It was concluded that palatal surgery as performed in this study has no influence on vertical and antero-posterior maxillary growth; only transverse palatal growth is influenced to a minor degree, especially when surgery is performed before or during the eruption of the permanent posterior teeth.

Animals↗

Oro-nasal fistula development and velopharyngeal insufficiency following primary cleft palate surgery--an audit of 148 children born between 1985 and 1997.

We present an audit of primary cleft palate surgery in our unit including rates of two important post-operative complications. Multidisciplinary audit clinics ran from March 1998 to April 2002 to follow up all local patients with a cleft lip or palate who had undergone primary palatal surgery in our unit. One hundred and forty eight patients were studied. Patient ages at follow-up ranged from 3 years and 10 months to 17 years and 4 months. Two surgeons performed the primary surgery. One hundred and twenty eight Wardill-Kilner and 20 Von Langenbeck repairs were performed. We found a 4.7% rate of oro-nasal fistula development requiring surgical closure, and a 26.4% rate of velopharyngeal insufficiency (VPI) requiring subsequent pharyngoplasty. We noted that the type of cleft involved affected the rate of VPI, 16% of patients with unilateral cleft lip and palate versus 29.2% of patients with a solitary cleft palate requiring secondary surgery. Outcome of surgery was determined by a 'Cleft Audit Protocol for Speech' (CAPS) speech therapy assessment at follow-up clinics. Only 14.9% of all patients assessed demonstrated any degree of hypernasality. Our results compare favourably with other recent studies including the Clinical Standards Advisory Group (CSAG) report into treatment of children with cleft lip and palate.

Adolescent↗

Somatosensory evoked magnetic fields to air-puff stimulation on the soft palate.

Impairment of sensory input to the soft palate has been reported in patients with obstructive sleep apnea syndrome. To investigate the reaction in the central nervous system related to soft palate perception, we measured the somatosensory evoked magnetic fields following air-puff stimulation in seven healthy volunteers by using a helmet-shaped 122-channel neuromagnetometer. The air-puffs were produced using compressed nitrogen and directed to the middle of the soft palate with an intraoral device. To evaluate the laterality of responses we used another appliance in which the air-puffs were directed to the middle and right side of the soft palate. In all the subjects, responses were identified symmetrically in the bilateral parietotemporal regions with a mean latency of about 130 ms from the soft palate stimulation. Prior to this peak, no distinct early responses were observed. There was no significant difference in the responses between the middle and right side stimulation. Corresponding equivalent current dipoles were estimated around the Sylvian fissures. These results suggested that the responses were derived from the second somatosensory areas. In conclusion, we could record long-latency responses to air-puff stimulation of the soft palate in the bilateral second somatosensory areas.

Adult↗

Is permanent maxillary tooth removal without palatal injection possible?

OBJECTIVE: The aim of the present study was to demonstrate if articaine HCl could provide palatal anesthesia in maxillary tooth removal without the need for a second palatal injection. STUDY DESIGN: Of 53 patients, 23 had bilateral and 30 had unilateral extractions. In the study group 2 mL of 4% articaine/HCl with 1:100,000 epinephrine was injected into the buccal vestibule of the tooth. After 5 min the extraction was performed. 27 subjects were controls and subjected to the same protocol with palatal injection. All patients completed a Faces Pain Scale (FPS) and a 100-mm Visual Analogue Scale (VAS) after extraction. RESULTS: According to VAS and FPS scores, when permanent maxillary tooth removal with palatal injection (97.5%) and without palatal injection (96.8%) were compared the difference was not statistically significant (P > .05) [corrected]. CONCLUSION: Permanent removal of maxillary teeth without palatal injection is possible by depositing 2 mL articaine/HCl to the buccal vestibule of the tooth.

Administration, Buccal↗