Mouth Closure Research Articles

The mechanism of chemical delivery to the vomeronasal organs in squamate reptiles: a comparative morphological approach

Vomeronasal chemoreception, an important chemical sense in squamate reptiles (lizards and snakes), is mediated by paired vomeronasal organs (VNOs), which are only accessible via ducts opening through the palate anteriorly. We comparatively examined the morphology of the oral cavity in lizards with unforked tongues to elucidate the mechanism of stage I delivery (transport of chemical-laden fluid from the tongue tips to the VNO fenestrae) and to test the generality of the Gillingham and Clark (1981. Can J Zool 59:1651-1657) hypothesis (based on derived snakes), which suggests that the sublingual plicae act as the direct conveyors of chemicals to the VNOs. At rest, the foretongue lies within a chamber formed by the sublingual plicae ventrally and the palate dorsally, with little or no space around the anterior foretongue when the mouth is closed. There is a remarkable conformity between the shape of this chamber and the shape of the foretongue. We propose a hydraulic mechanism for stage I chemical transport in squamates: during mouth closure, the compliant tongue is compressed within this cavity and the floor of the mouth is elevated, expressing fluid from the sublingual glands within the plicae. Chemical-laden fluid covering the tongue tips is forced dorsally and posteriorly toward the VNO fenestrae. In effect, the tongue acts as a piston, pressurizing the fluid surrounding the foretongue so that chemical transport to the VNO ducts is effected almost instantaneously. Our findings falsify the Gillingham and Clark (1981. Can J Zool 59:1651-1657) hypothesis for lizards lacking forked, retractile tongues.

Morphology of a picky eater: A novel mechanism underlies premaxillary protrusion and retraction within cyprinodontiforms

Upper jaw protrusion is hypothesized to improve feeding performance in teleost fishes by enhancing suction production and stealth of the feeding event. However, many cyprinodontiform fishes (mid-water feeders, such as mosquitofish, killifish, swordtails, mollies and pupfish) use upper jaw protrusion for “picking” prey out of the water column or off the substrate; this feeding mode may require improved jaw dexterity, but does not necessarily require increased stealth and/or suction production. We describe functional aspects of the bones, muscles and ligaments of the anterior jaws in three cyprinodontiform genera: Fundulus (Fundulidae), Gambusia and Poecilia (Poeciliidae). All three genera possess a premaxillomandibular ligament that connects the premaxilla of the upper jaw to the mandible. The architecture of this ligament is markedly different from the upper–lower jaw connections previously described for basal atherinomorphs or other teleosts, and this loose ligamentous connection allows for more pronounced premaxillary protrusion in this group relative to closely related outgroup taxa. Within poeciliids, a novel insertion of the second division of the adductor mandibulae (A2) onto the premaxilla has also evolved, which allows this jaw adductor to actively retract the premaxilla during mouth closing. This movement is in contrast with most other teleosts, where the upper jaw is retracted passively via pressure applied by the adduction of the lower jaw. We postulate that this mechanism of premaxillary protrusion mediates the cyprinodontiforms’ ability to selectively pick specific food items from the water column, surface or bottom, as a picking-based feeding mechanism requires controlled and coordinated “forceps-like” movements of the upper and lower jaws. This mechanism is further refined in some poeciliids, where direct muscular control of the premaxillae may facilitate picking and/or scraping material from the substrate.

Premaxillary movements in cyprinodontiform fishes: An unusual protrusion mechanism facilitates “picking” prey capture

Premaxillary protrusion is hypothesized to confer a number of feeding advantages to teleost fishes; however, most proposed advantages relate to enhanced stealth or suction production during prey capture. Cyprinodontiformes exhibit an unusual form of premaxillary protrusion where the descending process of the premaxilla does not rotate anteriorly to occlude the sides of the open mouth during prey capture. Instead, the premaxilla is protruded such that it gives the impression of a beak during prey capture. We quantified premaxillary kinematics during feeding in four cyprinodontiform taxa and compared them with three percomorph taxa to identify any performance consequences of this protrusion mechanism. Individual prey capture events were recorded using digital high-speed video at 250–500 frames per second ( n⩾4 individuals, ⩾4 strikes per individual). Species differed in the timing of movement and the maximum displacement of the premaxilla during the gape cycle and in the contribution of the premaxilla to jaw closing. Cyprinodontiform taxa produced less premaxillary protrusion than the percomorph taxa, and were consistently slower in the time to maximum gape. Further, it appears cyprinodontiforms can alter the contribution of the premaxilla to mouth closure on an event-specific basis. We were able to demonstrate that, within at least one species, this variability is associated with the location of the prey (bottom vs. water column). Cyprinodontiform upper jaw movements likely reflect increased dexterity associated with a foraging ecology where prey items are “picked” from a variety of locations: the bottom, water column, or surface. We postulate that dexterity requires slow, precisely controlled jaw movements; thus, may be traded off for some aspects of suction-feeding performance, such as protrusion distance and speed.

Lower lip reconstruction with a hard palate mucoperiosteal graft

Reconstruction of a lower lip deformity associated with leakage of saliva (drooling) and food spillage is challenging. To achieve complete closure of the mouth, the lips must have a sufficient and uniform thickness. Here we report a patient with lower lip deformity secondary to resection of a malignant tumor, in whom reconstruction was done with a hard palate mucoperiosteal graft. Perfect mouth closure without any leakage of saliva and a natural contour of the reconstructed lower lip were obtained, thus providing good aesthetic and functional results. This is the first report about the repair of a lower lip deformity with a hard palate mucoperiosteal graft. This type of graft seems to be a useful option for reconstructing lip deformities, and it can be widely applied to treat deformities caused by tumor resection, trauma, or cleft lip.

Outcomes 18 Months after the First Human Partial Face Transplantation

Background: We performed the first human partial face allograft on November 27, 2005. Here we report outcomes up to 18 months after transplantation. Methods: The postsurgical induction immunosuppression protocol included thymoglobulins combined with tacrolimus, mycophenolate mofetil, and prednisone. Donor hematopoietic stem cells were infused on postoperative days 4 and 11. Sequential biopsy specimens were taken from a sentinel skin graft, the facial skin, and the oral mucosa. Functional progress was assessed by tests of sensory and motor function performed monthly. Psychological support was provided before and after transplantation. Results: Sensitivity to light touch, as assessed with the use of static monofilaments, and sensitivity to heat and cold had returned to normal at 6 months after transplantation. Motor recovery was slower, and labial contact allowing complete mouth closure was achieved at 10 months. Psychological acceptance of the graft progressed as function improved. Rejection episodes occurred on days 18 and 214 after transplantation and were reversed. A decrease in inulin clearance led to a change in immunosuppressive regimen from tacrolimus to sirolimus at 14 months. Extracorporeal photochemotherapy was introduced at 10 months to prevent recurrence of rejection. There have been no subsequent rejection episodes. At 18 months, the patient is satisfied with the aesthetic result. Conclusions: In this patient who underwent the first partial face transplantation, the functional and aesthetic results 18 months after transplantation are satisfactory.

Morphology of the jaw system in trichiurids: trade-offs between mouth closing and biting performance

In this study, we focus on two piscivore species of cutlassfishes (Trichiuridae) that show some degree of differences in morphology of the jaw system: Aphanopus carbo and Trichiurus lepturus. As studies dealing with myological features of A. carbo and T. lepturus are presently lacking, we first provide a detailed description of the head musculature of A. carbo and T. lepturus. Secondly, we focus on the mechanics of the mouth closing system of these trichiurids by using biomechanical modelling. More specifically, models allows us to: (1) describe the differences between how the lower jaw lever system works during mouth closure and during generating static bite force; (2) evaluate the effects of morphological change on the performance of both functions; (3) determine whether the configuration of each component of the lower jaw lever system is a compromise between both functions, or whether there is a partition of function (optimization for either hard biting or fast jaw closing) between the different parts of the jaw closing musculature; and (4) discuss the dynamical implications of having elongate jaws for capturing prey. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 152, 717–736.

Cemento-ossifying fibroma-a rare case

The concept of 'fibro-osseous lesions' of bone has evolved over the last several decades and now includes two major entities: fibrous dysplasia and ossifying fibroma, as well as the other less common lesions such as florid osseous dysplasia, periapical dysplasia, focal sclerosing osteomyelitis, proliferative periostitis of garrie, and ostitis deformans. The cemento-ossifying fibroma is a central neoplasm of bone as well as periodontium which has caused considerable controversy because of confusion regarding terminology and the criteria for its diagnosis. The cemento-ossifying fibroma is odontogenic in origin, whereas ossifying fibroma is of bony origin. This article reports a rare case of an 11-year-old male who came to us with the history of swelling in the maxillary anterior region causing difficulty in closing of mouth as well as in mastication.

閉口障害を契機に診断された重症筋無力症の１例

Myasthenia gravis (MG) is an autoimmune disease of the skeletal neuromuscular junction, leading to a decreased number of postsynaptic acetylcholine receptors. Most MG patients complain of ocular muscle ptosis, diplopia, or both as initial symptoms. However, in extremely rare cases, MG initially presents with disturbed mouth closing. This paper describes a case of MG in a 41-year-old man who first consulted our department because of mouth closing insufficiency. At presentation, the patient's general condition appeared to be normal. He was able to open his mouth to a distance of 39 mm between the upper and lower central incisors. However, he could not bite more than 8 times, after which he needed to use his hand to close his mouth. There were no other symptoms such as temporomandibular disorder. We suspected MG and referred him to the Department of Internal Medicine of our center. Repetitive electromyography with low-frequency stimulation showed a typical decrement in the muscle action potential. The blood titer of anti-acetylcholine receptor antibody was 34 nmol/l. A thymoma was subsequently detected on chest CT. The patient was finally given a diagnosis of MG and received anticholinesterase agents. He was temporarily well. However, malaise gradually developed. After admission to our center, he suddenly had a myasthenic crisis, followed by cardiopulmonary arrest. The myasthenic crisis was managed by mechanical ventilation, immunoadsorption, and steroid pulse therapy, after he was successfully revived by cardiopulmonary resuscitation. Thereafter, he received additional treatment by extended thymectomy and post-irradiation.The patient has remained well, and there is no further mouth closing insufficiency. MG rarely presents with symptoms associated with the masticatory muscles. We should include MG in thedifferential diagnosis when examining patients with mouth closing insufficiency.

閉塞型睡眠時無呼吸症症例へのオーラルアプライアンス治療―補綴学的見地からの検討―

The patient was a 61-year-old woman with obstructive sleep apnea syndrome (OSAS) who was referred to our hospital for oral applianceOAtreatment. A mandibular advancing OA designed considering stomatognathic functions was fabricated. The OA was a one-piece maxillary splint and provided flat occlusal-plane guiding of the mandible into a therapeutic protrusive position at the mouth closing. OSAS indexes obtained by polysomnography after the OA treatment decreased than the values before treatment. No side effect was observed over the ensuing 3.5 years. It has been reported the OAs for OSAS incur a number of side effects such as disorders of stomatognathic function, teeth displacement, and change of occlusion. In this case, no such sign or symptom was observed. Proper design of OA might contribute to a favorable prognosis in OSAS patients. This report suggests that OA designed considering stomatognathic functions is effective against OSAS and prevents side effects.

Simulation study on mouth closure of the blue whale

U字型の吻部は、シロナガスクジラの頭骨の主たる特徴となっている。著者のひとりの大石は以前にナガスクジラ科鯨類の下顎骨の研究で、吻部の形態と密接な関係がある下顎骨について、次のように指摘した。シロナガスクジラの下顎骨は、水平面に置いたとき、関節部が内旋し筋突起が上方へのびるという独特の特徴をもつ。これに対してクロミンククジラでは、下顎骨は内旋せず、筋突起が上外方へのびる。両者の違いは吻部の形態に対応する。シロナガスクジラのU字型の吻部は下顎骨の長軸方向での内旋を必要としないが、クロミンククジラでは、口を閉じた状態で下顎骨とV字型の吻部との間の隙間を最小にするために下顎骨が内旋する。この状態では、クロミンククジラの下顎骨の関節部は内旋することになる。つまり、口を閉じたときにはシロナガスクジラもクロミンククジラも関節の状態は同等である。本研究では、3DCGソフトを使って上記のことを検証した。3Dシミュレーションの結果、大石の以前の研究の有効性が認められ、さらにシロナガスクジラ下顎骨挙上時に下顎骨がわずかに内旋することが新たにわかった。鯨類のような巨大な頭骨について、3DCGで以上のような状況を確かめることができる。

Facial expression categorization by chimpanzees using standardized stimuli.

The ability to recognize and accurately interpret facial expressions are critical social cognition skills in primates, yet very few studies have examined how primates discriminate these social signals and which features are the most salient. Four experiments examined chimpanzee facial expression processing using a set of standardized, prototypical stimuli created using the new ChimpFACS coding system. First, chimpanzees were found to accurately discriminate between these expressions using a computerized matching-to-sample task, and recognition was impaired for all but one expression category when they were inverted. Third, a multidimensional scaling analysis examined the perceived dissimilarity among these facial expressions revealing 2 main dimensions, the degree of mouth closure and extent of lip-puckering and retraction. Finally, subjects were asked to match each facial expression category using only individual component features. For each expression category, at least 1 component movement was more salient or representative of that expression than the others. However, these were not necessarily the only movements implicated in subject's overall pattern of errors. Therefore, similar to humans, both configuration and component movements are important during chimpanzee facial expression processing.

In situ growth of Soletellina alba (Bivalvia: Psammobiidae) in response to detrital supply and mouth status in a seasonally-closed estuary

The supply of detritus is an important food source for many soft-sediment invertebrates, but its importance for their growth and condition is rarely, if ever, tested directly using manipulative field experiments. Therefore, we designed such a study to: (1) test the importance of fine particulate organic matter for the growth and condition of the infaunal bivalve Soletellina alba; (2) indirectly test the feeding mode of S. alba, which has been assumed to be a deposit feeder like other members of the same superfamily (Tellinoidea); (3) compare growth rates across two summers with contrasting patterns of estuary mouth opening/closing; and (4) compare the condition of individuals used in two field studies (i.e. present versus past) and a past laboratory study. Neither growth nor condition differed when organic content of the sediments was varied, which suggests that S. alba is either a suspension feeder or capable of switching modes of feeding. There was considerable interannual variation in growth with greater growth occurring during the summer with a longer period of mouth opening. This suggests that periods of mouth closure may reduce secondary production within seasonally-closed estuaries. Potential artefacts associated with laboratory trials were also identified, with laboratory bivalves exhibiting poorer condition than those used in two field trials. The present study provides no evidence that variable quantities and qualities of organic matter within the sediments influence the growth and condition of S. alba, but future studies should focus on food supplied via the water column when the estuary is open versus closed.

Pharyngeal pressure with high-flow nasal cannulae in premature infants

The aim of this study was to measure pharyngeal pressures in preterm infants receiving high-flow nasal cannulae. A total of 18 infants were studied (median gestational age 34 weeks, weight 1.619 kg). A catheter-tip pressure transducer was introduced into the nasopharynx. Flow was sequentially increased to a maximum of 8 l min(-1) and decreased to a minimum of 2 l min(-1). There was a strong association between pharyngeal pressure and both flow rate and infant weight (P<0.001, r (2)=0.61), but not mouth closure. This relationship could be expressed as pharyngeal pressure (cm H(2)O)=0.7+1.1 F (F=flow per kg in l min(-1) kg(-1)). High-flow nasal cannulae at flow rates of 2 to 8 l min(-1) can lead to clinically significant elevations in pharyngeal pressure in preterm infants. Flow rate and weight but not mouth closure are important determinants of the pressure transmitted.

Intermaxillary fixation screws in mandibular trauma

Traditional maxillomandibular fixation with arch bar wiring to provide indirect stabilisation of the fractured jaws has long been replaced with miniplate osteosynthesis to reduce the duration of mouth closure. Therefore, a faster, safer and simpler method of maxillomandibular fixation for peri- and intraoperative stabilisation of jaw fractures has been tried as an option using intermaxillary fixation (IMF) screws. This study presents a review of 20 randomly selected cases of mandibular fractures treated by open reduction and internal fixation (ORIF) with miniplate osteosynthesis with peri/intraoperative use of IMF screws made of high resistance stainless steel, the use of which remains undocumented. The favourable results are an increased level of comfort for the operator, reduced working time therefore allowing time more efficient patient care as well as almost omitting the incidence of needle-stick type injuries due to limited use of wires and postoperative removal taking under 2 min in experienced hands. These advantages make it the preferred technique wherever possible, especially in hepatitis B, C and human immunodeficiency virus (HIV)-positive patients. The study is also aimed at sharing the experience in the use of IMF screws in terms of their number, placement and size, etc.

Declining catch per unit effort of an estuarine-dependent fish, Rhabdosargus sarba (Teleostei: Sparidae), in the marine environment following closure of the St Lucia Estuarine System, South Africa

Monitoring of catch per unit effort of the tropical stumpnose Rhabdosargus sarba in the St Lucia Marine Reserve between 2001 and 2005 revealed a significant decline. A similar decline was evident from shore patrol data collected by Ezemvelo KwaZulu-Natal Wildlife staff in the southern areas of the Greater St Lucia Wetland Park. As the distribution of fishing effort has decreased considerably since the promulgation of a beach vehicle ban in January 2002, this decline in the abundance of stumpnose has not been attributed to overfishing but rather to the closure of the mouth of the St Lucia estuary and lake system. The reason for this is because tropical stumpnose make extensive use of St Lucia as a nursery area and, since the mouth closure in June 2002, there has been no recruitment of juvenile fish into, or adult fish out of, the system. This emphasises the importance of estuarine nursery areas and highlights the need for ongoing catch and effort monitoring.

Functional Appliance Therapy to Control Drooling: A Case of A Child With Mental Retardation

A 12 year old male child with mental retardation was referred to the department of Pedodontics and Preventive Children Dentistry, AB Shetty Memorial Institute of Dental Sciences, Mangalore, with a complaint of severe drooling. Mouth closure exercises and speech therapy had failed to control the problem. The patient was given a functional appliance and a significant reduction in the severity of the drooling and reduction in the foul odor was found. Despite its limitations functional appliance therapy could serve as a useful alternative to the use of drugs or surgery in the control of drooling.

Fact or friction: a model for understanding the openability of wide mouth closures

AbstractUnderstanding and improving openability is becoming more and more important in the packaging industry. Specific tests or focus groups can be used to determine whether users have problems with packaging; however, these are both time consuming and expensive. This paper outlines a method by which it is possible to predict openability for any kind of closure by utilizing simple and quick tests, and by mathematically adapting strength test data. The method is demonstrated on wide mouth closures, and shows that there are optimum values for jar diameter and friction for containers of this type to enable increased openability. The data indicates that the optimum diameter for a jar lid is around 73mm, and therefore lids of this diameter are the easiest for consumers to open. The process outlined can be used to improve openability of packaging while keeping costs to a minimum. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Fish communities in temporarily open/closed estuaries from the warm- and cool-temperate regions of South Africa: A review

The majority of estuaries along the coastline of southern Africa are termed temporarily open/closed estuaries (TOCEs) and are closed off from the sea for varying periods by a sandbar which forms at the mouth. It is therefore important to understand the processes occurring within TOCEs and their importance to fishes in order to make sound management recommendations. Estuaries along the coast of South Africa and their associated fish assemblages are biogeographically distinct and occur in either a subtropical, warm-temperate or cool-temperate zone. There are 125 TOCEs found within the cool-temperate and warm-temperate zones. Most fish species found in TOCEs are the juveniles of marine taxa that breed at sea. Permanently open estuaries generally have a higher diversity of species than TOCEs, but TOCEs still provide important nursery areas for many marine species and numerically often have a higher proportion of estuarine resident species. Important taxa in terms of abundance and biomass in warm-temperate TOCEs include the sparids Rhabdosargus holubi and Lithognathus lithognathus, several mugilid species, estuarine residents (particularly Gilchristella aestuaria and Atherina breviceps) and the freshwater cichlid Oreochromis mossambicus. The diversity of fishes in cool-temperate TOCEs is low when compared with warm-temperate systems and Liza richardsonii tends to dominate catches by number and mass in most systems. Several species recorded in TOCEs show clear longitudinal distribution trends. For example Atherina breviceps is generally more abundant in the lower reaches of estuaries. Mouth state, particularly the frequency, timing and duration of mouth opening plays a key role in determining species richness, composition, diversity and abundance in TOCEs. Mouth state is directly linked to freshwater input. Reduced river inflow leads to prolonged mouth closure and shorter open phases, which inhibits immigration and emigration of marine fish species between estuaries and the sea. Understanding of the effects of various processes occurring within these systems, particularly variation in freshwater input, on the biota of these important systems facilitates the development of informed management recommendations.

Comparison of Inter-Twin Concordance in Symptoms of Temporomandibular Disorders: A Preliminary Investigation in an Adolescent Twin Population

There is controversy as to the genetic contribution to the pathogenesis of temporomandibular disorders (TMD). Several reports reveal a marked familial aggregation in the signs and symptoms of TMD, while others do not. Therefore, our goal was to investigate the hypothesis using a sophisticated research design, which was a well-known genetic survey inter-twin concordance assessment in the symptoms of TMD. This study is the first step to survey TMD symptoms of a twin group in junior and high schools as a preliminary trial. The 63 twins were asked to participate in this study in junior and senior high schools affiliated with the University of Tokyo, Japan, schools which kept ten twins in each grade for the purpose of several genetic survey programs. After excluding incomplete filling out of questionnaire sheets and data from male-female pairs, 43 monozygotic (MZ) (15.3±1.7 yrs, male/female = 17/26 pairs) and nine dyzygotic (DZ) (15.2±1.8 yrs, male/female = 6/3 pairs) twins were studied. Outcomes consisted of a prevalidated 14-item self-administered questionnaire, which assessed proband- and pair-wise concordance levels in the MZ and DZ twins. These results demonstrated that the MZ twins had a higher tendency of inter-twin concordance than DZ twins in terms of jaw pain in wide mouth opening (proband-wise concordance = 66.7% in MZ, 0% in DZ), difficulty in mouth opening (20% in MZ, 0% in DZ) and difficulty in mouth closing (50.0% in MZ, 33.3% in DZ), while there was no significant difference between the MZ and DZ concordance levels in other general health-related and behavior- related items, except toothache. However, the pair-wise concordance rates of jaw pain in wide mouth opening and difficulty in mouth opening in the MZ twins were not significantly higher compared to the DZ rate. Possibly, a genetic factor contributed to the pathogenesis of TMD in an adolescent population. The sample size needs to be increased, and there are plans to survey the next sample in the same schools.

Seasonal and diel comparisons of the diets of four dominant fish species within the main channel and flood-zone of a small intermittently open estuary in south-eastern Australia

The diets of four highly-abundant, dominant fish species within the Surrey River, a small intermittently open estuary in south-east Australia, were examined from specimens collected between July 2004 and June 2005. These four, similar-sized species (Atherinosoma microstoma, Galaxias maculatus, Philypnodon grandiceps and Pseudogobius olorum) have limited ability to spatially segregate along the length of the estuary owing to its small size relative to other estuarine habitats. All four species fed on a variety of prey items including crustaceans, insects and detritus. Despite this parity, the four species were demonstrated to occupy differing dietary niches that were concluded to be responsible for reducing interspecific feeding competition. Seasonal variations in the diets were observed for A. microstoma and Philypnodon grandiceps, with these species also exhibiting contrasting diel feeding behaviours. The closure of the estuary mouth led to the flooding of its margins, resulting in an increase in the size of the estuary and providing alternative food resources for the fish to exploit. It appears the inundation of the flood-zone facilitated further significant divergence in the diets of the fish and is likely to be of high ecological value to the estuary.