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We present a case of atrophy of the masticatory muscles due to a masticatory habit. The patient has had only left side molars for about 40 years. The atrophy of the masticatory muscles was detected incidentally when a brain radiological examination was performed. The patient had no subjective complaints on mastication.
The aim of the study was to asses the anatomic and functional results and quality of life of a cohort of patients submitted to immediate reconstruction with the iliac osteomusculocutaneous free flap following composite resection for carcinoma of the oral cavity. Twelve patients affected by squamous cell carcinoma of the oral cavity were submitted to a single surgical procedure that included a segmental mandibulectomy in a composite resection, followed by primary reconstruction using a vascularized bone-containing free flap of the iliac crest. Reconstruction failed in one patient. Functional results as well as quality of life of 10/12 patients were evaluated using the Performance Status Scale and Functional Assessment Cancer Therapy General Scale questionnaires, appropriately modified for the pathology. The results were compared with those obtained in a group of five patients who underwent composite resection for oral carcinoma without mandibular reconstruction. Patients submitted to reconstruction noted a greater physical well being (score 22/78% vs. 16/53%; max. 28/100%), socio-family relationships (score 23/81% vs. 18/64%; max. 28/100%), emotional (score 18/90% vs. 14/70%; max. 20/100%) and general functional well-being (score 24/86% vs. 14/50%; max. 28/100%). Better recovery in functional mastication and swallowing was also observed (score 17/70% vs. 9/37%; max. 24/100%). A follow-up of longer than 6 months showed minimal donor site morbidity.
We reviewed the topic of atypical lipomatous tumors including definition, diagnosis and management, with special emphasis on head and neck location and to report on the management of a rare case located in the temporalis muscle. Atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLS) are rarely reported in the head and neck. Their behavior dictates a complete resection. Resection with a safety margin is sometimes needed according to the histological characteristics. Tumors located to the masticator space can be accessed through a mucosal approach achieving relative safety to the facial nerve. ALT constitute a group of tumors of a borderline behavior. Their management can be affected by some histological criteria and by their location in the head and neck region where vital structures can be affected.
The goal of this study was to examine deglutitive physiology during sequential straw drinking in healthy young adults (n = 15) to learn how sequential swallowing differs from single swallows. The physiology of single swallows has been studied extensively in healthy adults and in adults with a variety of debilitating conditions, but the physiology of sequential swallows has not been studied adequately. Videofluoroscopic analysis revealed three distinct patterns of hyolaryngeal complex (HLC) movement during sequential straw swallows: opening of the laryngeal vestibule after each swallow (Type I, 53%), continued vestibule closure after each swallow (Type II, 27%), and interchangeable vestibule opening and closing during the swallow sequence (Mixed, 20%). Unlike discrete swallowing, the onset of the pharyngeal swallow occurred when the bolus was inferior to the valleculae in the majority of subjects and was significantly associated with HLC movement pattern. The leading bolus edge was inferior to the valleculae at swallow onset for Type II movement patterns. For Type I movement patterns, bolus position at swallow onset was randomly distributed between three anatomical positions: superior to the valleculae, at the level of the valleculae, and inferior to the valleculae. Preswallow pharyngeal bolus accumulation, which is common during mastication, was evident and significantly associated with the HLC pattern of opened laryngeal vestibule after each swallow. These data suggest that in healthy young adults, sequential swallows differ physiologically from discrete swallows and indicate substantial variability in deglutitive biomechanics.
This study was designed to determine visible and measurable morphological parameters in normal swallowing using dynamic MRI with single-shot fast spin echo (SSFSE), as a preliminary study in view of noninvasive MRI swallowing evaluation in patients with dysphagia. Seven healthy volunteers aged 24-40 underwent dynamic MRI with SSFSE, with a 1.5-T unit, using a head and neck antenna. Patients repeated dry swallow, water swallow, marshmallow swallow, cake swallow, and cookie chewing for a total of five series, with 15 acquisitions per series at a rate of 700 ms per acquisition. A checklist of swallowing events and anatomic landmarks was used to determine which anatomic landmarks are always visible, which phases or swallowing movements are always visible, and which landmarks can be used to measure oral and pharyngeal motion in swallowing. The oral preparatory, oral, and oropharyngeal phases of deglutition were visible in all cases. No aspiration, reflux, or abnormal residue was observed. Spatial resolution allowed for anatomical measurements of laryngeal elevation, oropharyngeal diameter, and tongue base and velum displacement in all cases. SSFSE dynamic MRI is pertinent for evaluation of the anatomical and physiological characteristics of swallow. The temporal parameters, however, cannot be studied using this technique. Motion artifacts preclude its use in the study of mastication. It remains complementary to videofluoroscopy and other techniques in swallow evaluation.
This study examined the frequency of penetration of liquid, paste, and masticated materials into the airway during videofluoroscopic studies of normal swallow in 98 normal subjects who were from 20 to 94 years of age. The purposes of the study were to define frequency and level of penetration using the penetration-aspiration scale as a result of age, bolus volume, viscosity, and gender, and to describe the body's sensorimotor response to the penetration based on audible coughs or throat clearing on the audio channel of each videotaped fluoroscopic study. Frequencies of penetration were defined in relation to bolus volume, age, gender, and bolus viscosity from swallows of 1, 3, 5, and 10 ml and cup-drinking of thin liquids; 3 ml of pudding; (1/4) of a Lorna Doone cookie; and a bite of an apple. Results showed that penetrations were significantly more frequent after age 50 and thick viscosities penetrated only in subjects age 50 and over. For persons under 50, 7.4% of swallows exhibited penetration, while for people age 50 and over, 16.8% of swallows showed penetration. Significantly more penetration occurred on larger liquid boluses. There was no relationship between gender and frequency of penetration. None of the subjects that penetrated showed a sensorimotor response to the penetration, which may relate to the relatively shallow depth of the penetration.
To overcome the shortcomings of the conventional composite restorative materials, ormocer materials have been introduced over the past few years. The purpose of this study was to evaluate the marginal and internal adaptation of two ormocer restorative systems (Admira, Voco and Definite, Degussa) compared to a hybrid composite one (TPH Spectrum, Dentsply/ DeTrey), before and after load cycling in Class II restorations. Standardized Class II restorations with cervical margins on enamel were divided into three groups ( n=16). Teeth of each group were filled with one of the restoratives tested and its respective bonding agent. Each group was divided into two equal subgroups. The marginal and internal adaptation of the first subgroup was evaluated after 7-day water storage at room temperature and of the second after cyclic loading in a mastication simulator (1.2x10(6) cycles, 49 N, 1.6 Hz). The occlusal and cervical marginal evaluation was conducted by videomicroscope and ranked as "excellent" and "not excellent". One thin section (150 microm), in mesial-distal direction, of each restoration, was examined under metallographic microscope to determine the quality of internal adaptation. The occlusal and cervical adaptation of both ormocer restorative systems was similar and clearly worse compared with the hybrid composite restorative one before as well as after load cycling. Concerning internal adaptation, no gap-free ormocer restorations were detected, whereas all Spectrum restorations presented perfect adaptation. The bonding agents of the ormocers formed layers with unacceptable features (pores, fractures) whereas that of the hybrid composite achieved perfect bonding layer even after loading. The rheological characteristics of the bonding agents of the ormocer restorative systems are proposed to be responsible for their inferior marginal and internal quality in Class II restorations compared with the hybrid composite one.
BACKGROUND: The aim of the study was to analyze the influence of possible temporary or permanent disorders of sensation on the degree of the patient's satisfaction following an orthognathic operation. PATIENTS AND METHODS: After an average of 47 months (range: 9-141), a follow-up examination was performed in 78 women (64.5%) and 43 men (35.5%) with an average age of 24.3 years (range: 19-40) at the time of operation. In 67 cases there had been a sagittal division of the mandible, in 11 cases a Le Fort I osteotomy, in 26 cases a bimaxillary osteotomy, in 4 cases an isolated genioplasty, and in 13 cases a segmental osteotomy in the upper or the lower jaw. In the peripheral area supplied by the nerves V2 and V3 sensation was examined by the two-point discrimination test and the result related to the patients' satisfaction using the chi-square test. RESULTS AND DISCUSSION: The following qualities of sensation were recorded: anesthetic (2.7%), hypesthetic (16.6%), paresthetic (8.3%), and normesthetic (72.4%). The patients' satisfaction was rated as very satisfied in 51.3%, as satisfactory in 44.8%, and in 3.9% the patients' expectations had not been fulfilled; 75% regarded their outward appearance as markedly improved and a good 50% of the patients noted improved mastication. Therefore, three-fourths of all the patients would even be willing to be operated on again. Two-dimensional analysis, however, demonstrated only a weakly significant positive relationship between patient satisfaction and the preserved, or restored, sensation in the trigeminal region.
Bruxism is generally defined as a parafunctional clenching and grinding action between the upper and lower teeth. During this activity, extremely strong forces can be applied for time periods exceeding those of functional mastication. These biomechanical loads create many dental problems, such as abfractions, hypersensitivity, periodontal distraction, and temporo-mandibular dysfunction. Researchers studying Bruxism have long discussed psychic stress and emotional tension. It has also been indicated that an aggressive biting is associated with a significant attenuation of the stress-induced increase of nor-adrenalin turnover in the brain, of the striatal DOPAC contents and with the prevention of stomach ulcer formation in experimental animals. The concept of stress management based on the psychological background of Bruxism and the benefits attributable to masticatory muscle activity in attenuating stress-related symptoms such as stomach ulcer. The clenching and bruxing function of the masticatory organ is an emergency exit during periods of psychic overloading. Therefore, occlusion of the masticatory organ contributes significantly to an individual's ability to manage stress. Bruxism in proper dentition can be recognized as a valid system prophylaxis for all stress related diseases.
Pain caused by temporomandibular disorders originates from either muscular or articular conditions, or both. Distinguishing the precise source of the pain is a significant diagnostic challenge to clinicians, and effective management hinges on establishing a correct diagnosis. This paper examines terminology and regional anatomy as it pertains to functional and dysfunctional states of the temporomandibular joint and muscles of mastication. A review of the pathophysiology of the most common disorders is provided. Trends in evaluation, diagnosis, treatment, and research are presented.
Fifty-three subjects were examined for mandibular asymmetry using measurements from submental-vertex and frontal cephalograms. All subjects displayed malocclusions and were examined for sensitivity of the muscles of mastication to palpation. The amount of pretreatment pain to muscle palpation was then correlated to the degree of asymmetry found. No statistically significant correlation was shown between mandibular asymmetry and muscle sensitivity. The following conclusions were drawn from this study: 1. There was no correlation between the amount of mandibular morphologic asymmetry and the amount of facial pain elicited from muscle palpation. 2. In the sample used, asymmetry seemed to be the rule rather than the exception. 3. The clinician needs to be aware of asymmetry in all three planes of space in order to plan his occlusal treatment in advance and prepare patients for possible compromise. 4. Class II molar and canine relationships may be more difficult to correct on the patient's right side than on his left, provided there is no compensation from glenoid fossa position or the maxillary dentition.
In thirty-three of sixty-six guinea pigs of the Topeka strain small, unilateral, electrolytic lesions were produced in the motor nucleus of the trigeminal nerve. Unoperated animals and the side contralateral to the muscle paralysis served as controls. Lesions were created when animals were 15 days or 75 days of age, and the animals were killed 15, 30, 45, or 60 days postoperatively. Each animal was subjected to dry skull preparations or radiographic and histologic techniques. Alterations in craniofacial form were noted in both the growing animals and the animals with little growth remaining. Alterations in form and function included paralysis and atrophy of the muscles of mastication on the lesion side, hypereruption of teeth, and reduction in growth of facial bones on the lesion side. Remodeling changes were evident in the glenoid fossa, the condylar process, and the coronoid process on the operated side but were not apparent in the contralateral control or the unoperated control animal.
In two adolescent male Macaca mulatta monkeys, small unilateral electrolytic lesions were produced in the motor nucleus of the trigeminal nerve. The side contralateral to the muscle paralysis served as the control side. The animals were killed 130 and 300 days postoperatively. One animal (animal A) was prepared as a dry skull preparation. Alterations in craniofacial form were noted clinically in both animals and included paralysis and atrophy of the muscles of mastication on the lesion side and mandibular asymmetry. In animal A (300 days postoperative survival), alterations in form included dental and mandibular asymmetry, the appearance of an anterior open-bite on the affected side, and a decrease in the size of the intratemporal fossa on the affected side. Remodeling changes were evident in the condylar process, the zygomatic arch, the orbit, and the zygomaticotemporal and zygomaticofrontal sutures on the lesion side but were not apparent on the contralateral side.
This article presents an appliance system designed to facilitate efficient treatment by the use of the biomechanical approach considered most suitable by the orthodontist for the individual patient. The system described uses narrow, single brackets with 0.022 X 0.028 inch edgewise arch wire slots and 0.020 X 0.020 inch vertical slots for various auxiliaries. There are five brackets that differ only in the torque of the arch wire slot-0 degree, 5 degrees, 10 degrees, 15 degrees, and 20 degrees. Thus, an appropriate bracket can be selected for any tooth in any situation. The brackets and bonding pads are small in all dimensions to ensure optimal appearance and interbracket arch wire spans and minimal lip and cheek irritation. This also lessens occlusal interference, enamel surface involved in bonding, and problems with gingival proximity and oral hygiene. The basic buccal tubes are conventional 4.5 mm long, 0.022 X 0.028 inch torqued edgewise tubes. A buccal tube assembly with a similar additional rectangular tube carried diagonally at a 15 degree angle across the buccal surface of the basic tube (its mesial end pointing gingivally) is used in extraction cases with deep overbites or moderate-to-severe anchorage requirements. The angulated outer tube carries the main (working) arch wire during the bite-opening and retraction phases of treatment. A rectangular sectional wire in the inner tube and second premolar bracket locks the molar and premolar teeth together so that neither can tip independently. As a unit they provide anchorage for bite opening and retraction. The gingivally positioned and angulated outer tube directs the arch wire out of danger of distortion from mastication and provides a built-in biteopening effect. The molar and premolar teeth, in effect, become a single large tooth with its center of resistance (CR) further mesial than the CR of the molar. Sectional wires result in a more favorable system of moments created by arch wires and elastics. This delivers more intrusive force to the incisors with less tendency to tip the anchor units. The appliance provides the orthodontist with an extensive range of options in treatment mechanics--from anchorage conservation and rapid movement of limited tipping by light forces to translation or stabilization with precise three-dimensional control.
Frey's syndrome occurs after parotid gland surgery or injury to the parotid gland and is characterized by gustatory sweating and erythema of the face upon mastication. The syndrome occurs in 50 to 60 per cent of all patients undergoing parotid surgery but the symptoms are only distressing to about 10 per cent of patients undergoing parotidectomy. A case of Frey's syndrome is reported The patient obtained good relief of symptoms with scopolamine cream and atropine cream. Other methods of therapy are discussed along with their limitations. Noninvasive therapy with topical anticholinergic creams is effective and seems appropriate in the control of gustatory sweating.
Rats were fed a stock pelleted diet (control diet) or the same stock diet to which 30 per cent non-nutritive cellulose had been added (bulk diet). The control diet and the bulk diet were fed to rats in two consistencies, pelleted or ground. Compared to the parotid glands of rats fed the pelleted control diet, those of rats fed either of the ground diets were not different, but parotid gland wet weight, DNA and RNA content and total gland amylase and protein were significantly greater in rats fed the pelleted bulk diet for 2 wk. The cell indices of RNA/DNA and amylase/DNA were significantly greater in rats fed the pelleted bulk diet, but were not significantly changed in rats fed the ground bulk diet. Thus there is a significant increase in cell number and cell content of amylase when rats are fed a bulk diet that is pelleted and no such increases are found when the bulk diet is ground. The findings support the contention that the physical consistency of the diet and its requirement for mastication are major factors contributing to the regulation of parotid-gland size and secretory-enzyme content.
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.
Analysis of the many X-ray diffractograms obtained from the regions along the bands of Hunter-Schreger, and a series of X-ray patterns taken by tilting the specimen with respect to the incident X-ray beam over a wide range of tilt angles, showed that the fibre axis of the crystal aggregates in each zone of the bands not only deviated in opposite directions but also tilted at an angle of about 50 degrees with respect to the central axis of tooth enamel. Comparison with previous studies enabled a fundamental and simplified three-dimensional model of human cusp enamel to be constructed, consisting of two groups of spirally-arranged structure which would probably be elastic enough to fulfil its unique functions in occlusion and mastication.