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At least 1,081 records · Page 60Linked to original sources
PubMed1999

Association between loss of occlusal support and symptoms of functional disturbances of the masticatory system.

The purpose of this study was to evaluate the association of loss of occlusal support with symptoms of functional disturbances of the masticatory system, in particular with the ones related to the temporomandibular dysfunction. A total of 483 adult subjects randomly selected from the population living in the municipality of Segrate, northern Italy, were studied. Subjects were interviewed by questionnaire about oral conditions and occurrence of symptoms of disturbances of the masticatory system. Also, denture was examined by dentists during the interview. Loss of occlusal support was observed in 60.2% of the subjects, symptoms of functional disturbances in 68.7% and temporomandibular dysfunction in 55.1%. At univariate analysis loss of occlusal support was mainly associated with a feeling of stiffness or fatigue of the jaws (P < 0.001), difficulty in closing the mouth (P < 0.005) and difficulty on mastication (P < 0.0001). Association with temporomandibular dysfunction as a whole was significant also (P < 0.001). Multiple age- and sex-adjusted logistic analysis disclosed a significant strong impact of loss of occlusal support on difficulty with mastication (odds ratio = 7.0, P < 0.0001). At that analysis, no significant relationship resulted with symptoms of temporomandibular dysfunction. These findings confirm that presence of an adequate occlusal support is a relevant factor in maintaining an efficient chewing, and also suggest that it may play any indirect role in preventing occurrence of symptoms of temporomandibular dysfunction.

Adolescent↗
PubMed2000

Chewing ability and quality of life among the elderly residing in a rural community in Japan.

The present study statistically evaluates the relationship between chewing ability and quality of life (QOL) in elderly Japanese residents. We used a subjective evaluation and a mastication score determined by the food intake status to evaluate chewing ability. The PGC morale scale was used to evaluate the QOL level. The mastication score was significantly related to the QOL level in the subject group (P<0.05). The relationship between the subjective evaluation of chewing ability and the score on the PGC morale scale showed a similar tendency. In the section of the PGC morale scale that assesses agitation, attitude towards own aging, and lonely dissatisfaction, chewing ability was correlated with attitude toward own aging in particular (P<0.05). These results have suggested that the chewing ability is closely related to the QOL of the elderly residing in a rural community in Japan.

Aged↗
PubMed2001

"The first bite of the cherry": Intra-oral manipulation prior to the first bite in humans.

The breakdown of food in the mouth during mastication can be described in terms of two parameters: a breakage function, which describes the fragmentation of food after a bite, and a selection function which defines the probability of particle fracture. The non-zero value of the selection function depends on the manipulation of food particles by the tongue. Little, however, is known about this. As a first step, this study investigated the manipulation of wax sheets of differing sizes and shapes by the tongue after ingestion. It was found that subjects tended to orientate rectangular and square wax wafers so that the long axis of the particle was parallel to the tooth row, independent of the initial orientation given when they were introduced into the mouth. Circular wafers were randomly oriented relative to initial orientation. If this could be extrapolated to the start of mastication, then it suggests that the tongue tends to align food particles so that the post-canines produce close to the greatest surface area possible by fragmenting them along their longest axis.

Eating↗
PubMed2001

Patient evaluation of treatment with fixed implant-supported partial dentures.

The aim of this study was to analyse the patient evaluation of functional treatment outcome in 40 periodontally compromised patients who received implant-supported prostheses (ISPs) as part of the total treatment. The treatment protocol comprised periodontal treatment, extraction of teeth with poor prognosis, placement of dental titanium implants, and after healing, insertion of fixed ISPs. Five of the patients became edentulous in one jaw after extraction of all teeth and received a complete ISP, whereas 35 patients became partially edentulous after extraction of some teeth, 12 receiving a partial ISP on > or = 3 implants, and 23 one on two implants. The follow-up period was on average 1.8 years after the connection of the prostheses, which provided the patients a dentition with a mean of 12 occluding dental units. The first author (S.-W. Yi) performed all implant treatment. Patients' opinions on oral functions--mastication, phonetics, oral hygiene, chewing comfort and aesthetics--were evaluated by means of a questionnaire both before implant installation and at the last follow-up. A control group of 30 subjects with a healthy dentition of 14 occluding natural pairs of teeth answered the same questionnaire on one occasion. A great majority of the patients were extremely satisfied with the oral function after treatment and experienced the ISPs as 'natural teeth'. There was no significant difference between the three treatment groups and the control group for mastication, phonetics, chewing comfort and aesthetics. Patients with ISPs reported a small but significantly greater difficulty with oral hygiene procedures than the controls with natural teeth. Most patients said that they would undergo the treatment again, if necessary, and recommend it to others. It was concluded that the rehabilitation of the periodontally compromised patients, including ISPs on osseointegrated dental titanium implants, resulted in subjectively improved and satisfactory oral function.

Adult↗
PubMed2003

A comparison of the methods used to determine chewing preference.

For much human activity there exists a 'lateral preference', that is a tendency to use one side of the body or the other; with respect to the hands for example, the vast majority of individuals have a preference for either the right or left hand. Most experts agree that mastication is no exception in that there is a 'preferred chewing side' but the determination of this preference is somewhat complex. This research analyses the mastication of 60 healthy subjects by means of preferred chewing side or 'PCS' tests, the Kazazoglu test, and kinesiography (KGF). While some authors consider the PCS to be the side which first comes into contact with the food we prefer to define it as the side on which the majority of the cycles analysed and registered take place. The objective of this research was to analyse the relationship that might exist between the two different methods used for determining a lateral chewing preference. Although there was no statistically significant agreement between the two techniques, both reflected the fact that there was a marked preference for the right hand side.

Adult↗
PubMed2006

[Occlusal justification of early treatment of Class III malocclusions].

Authors mostly admit that Class III treatment has more chance of success and stability if it is carried out precociously. Their conviction is primarily based on the use of patient's growth potential. This aspect does not seem to be the main interest of early treatment. The length of the occlusal plane and its impact on mandibular movements (mastication), which can influence growth and maxillomandibular relationships, accounts or even constrains to act as soon as possible. The fundamental objective of early Class III treatment would be the reorientation of the occlusal plane and the rehabilitation of mastication would be the final goal, ensuring an active and physiological result's retention.

Age Factors↗
PubMed1981

Flow rates in the head and neck lymphatics after food stimulation in healthy subjects. Clinical value.

In 22 healthy subjects lymph transport flow rates was studied in the head lymphatics after food stimulation, mastication (chewing) and taste. After food stimulation there was a significantly higher transport rate (0.67 meter/hour) than after taste (0.57 meter/hour) and mastication (0.55 meter/hour). The calculation of transport flow rate was independent of quantitative distribution of radioactivity in the head and neck lymphatics, and it could therefore perhaps be of clinical value.

Adult↗
PubMed2003

Clinical ligation forces and intraoral friction during sliding on a stainless steel archwire.

The efficiency of tooth movement associated with some orthodontic mechanics can be compromised by friction between archwire and bracket. This study examined the effects of bracket ligation forces (F(N Ligation)) and mastication on friction when sliding a bracket along an archwire. Preliminary data from 5 orthodontists and 5 orthodontic residents characterized average tight and loose stainless steel F(N Ligation). These values were reproduced by a calibrated operator in a custom device used to estimate changes in the measurement of ex vivo and intraoral frictional forces, represented by mu(a), the apparent coefficient of static friction. Ten subjects chewed gum with the device in place to determine whether vibration eliminated friction when compared to ex vivo measurements. Nested analysis of variance and Tukey HSD tests determined the effects of ligation type and environmental variables. No significant differences (P >.01) were found between ex vivo and intraoral mu(a) values for tight and loose stainless steel ligation. Intraoral mu(a) values for elastic ligation were significantly greater than ex vivo mu(a) values (P <or=.001). The results suggested that vibration introduced by mastication did not eliminate friction when sliding a bracket along an archwire. In addition, there was considerable intraoperator variation in F(N Ligation), although ligation techniques were well controlled. Variations in clinical ligation forces are likely to be equal or greater than these experimental data. These variations could affect treatment efficiency.

Analysis of Variance↗
PubMed1997

Masticatory tooth contact patterns: predicted and observed cuspid and first molar contacts in cuspid and group function.

Using the mouth as an "in vivo articulator," the bilateral nonmasticatory ("empty") contact patterns of opposing cuspid and first molar teeth were determined in two healthy subjects with well-defined cuspid function and two healthy subjects with well-defined group function. The electronically recorded "empty" contact patterns pertained to the static intercuspal position and dynamic laterotrusion to the right and the left. On the basis of the "empty" tooth contact patterns and the number of electronically recorded masticatory cycles of one masticatory sequence, we postulated two simple models that attempted to predict the masticatory ("functional") tooth contacts of one sequence of unilateral mastication of apple and banana. Statistical comparisons between the predictions of the two models and the actual ("functional") contacts of in vivo mastication showed that the models predicted fairly well the observed tooth contacts on the nonchewing-side of the mouth, but not the observed tooth contacts on the chewing-side of the mouth. In consequence, "empty" (nonmasticatory) tooth contact patterns should not be equated with "functional" (masticatory) tooth contact patterns.

Adult↗
PubMed2001

Tooth wear: use of overlays with metallic structures.

This work is a clinical case report of a patient presenting with marked tooth wear in all teeth, a reduction in the vertical dimension of occlusion, and fatigue in the muscles of mastication. The treatment proposed and effected used a muscle-relaxing appliance and mandibular and maxillary overlay appliances which were adjusted according to the occlusal contacts, vertical dimension of occlusion, and the mandibular positioning. The results obtained were satisfactory in terms of relaxing the muscles involved, reestablishing the dimensions of the lower third of the face, and the functional activities of deglutition, mastication, and speech.

Adult↗
PubMed2003

Jaw deviation dystonia evaluated by movement-related cortical potentials and treated with muscle afferent block.

Jaw-deviation dystonia is characterized by the lateral shift of the mandible due to involuntary masticatory muscle contraction, causing difficulties in speech or mastication. We evaluated a patient with jaw-deviation dystonia by recording movement-related cortical potentials (MRCPs) and treated with muscle afferent block (MAB). MRCP associated with mandibular movements (mouth opening, closing, and left and right lateral movements) was recorded in the patient and ten age-matched healthy subjects. In the control subjects, the amplitude of Bereitschaftspotential (BP)/negative slope (NS') was significantly higher for left lateral movements than for the mouth closing. The cortical map of BP/NS' prior to mouth opening and closing showed symmetric distribution, whereas those of lateral movements showed a slight predominance in the ipsilateral hemisphere. The patient showed lower amplitude as compared with control subjects. The right lateral movement (homonymous task) showed task-specific markedly reduced potentials. After MAB by intramuscular injection of lidocaine and ethanol to the inferior head of the left lateral pterygoid muscle, the deviation abolished and severity in speech and mastication was significantly improved. This study suggests that jaw-deviation dystonia might have the same etiology as other focal dystonias.

Adult↗
PubMed1981

Neural control of oral somatic motor function.

The control and regulation of mastication and other basic oral activities require integration by brain stem cranial nerve nuclei of reflex inputs and commands from other central nervous system nuclei. A current conceptual model for understanding control of rhythmic oral motor activity postulates the existence of a central pattern generator, which produces the sequence of movements common to many oral functional activities. According to this model, the output of the generator can be influenced by activity in cranial nerve afferents or modified by signals from other central nuclei. The central control model predicts that the threshold for reflex responses will change during the jaw opening and closing phases of mastication so that the effect of sensory stimulation will vary with the concurrent activity of the muscular and central nervous systems.

Animals↗
PubMedDate not supplied

The efficacy of adhesives in the application of wound dressings.

The use of adhesive preparations to reinforce surgical tapes and to secure dressings to the skin is standard practice. BioBrane is a biosynthetic membrane for use in dressing clean, well-debrided wounds, particularly partial-thickness burns and skin graft donor sites. The close and undisturbed contact of this material with the wound surface is important during the first 2 days after its application to achieve adherence. This has prompted a study to test the relative anchoring strength of four methods of securing the dressing to the normal skin around the wound: 1/2-inch (1.27-cm) Steri-Strips only; Mastisol, a mastic compound, with and without 1/2-inch Steri-Strips; and compound tincture of benzoin, USP, in combination with 1/2-inch Steri-Strips. The results obtained with a tension of 1.1 pounds/square inch (0.5 kg/6.5 cm2) were not conclusive as to the superiority of any one method. However, with a tension of 2.2 pounds/square inch (1 kg/6.5 cm2), the combination of mastic compound and 1/2-inch Steri-Strips provided the strongest adhesion. This type of application should also prove useful when other types of surgical dressings must be anchored in place.

Adhesives↗
PubMed1992

Masticatory function in hemimandibulectomy patients.

Surgical resection of a segment or loss of continuity of the mandible can adversely affect most of the structures essential for mastication. Five subjects who had hemimandibular resections for cure of squamous cell carcinoma were studied. Masticatory function tests were conducted pre- and post-surgery and post-prosthetic rehabilitation. A 0.5-g Frito corn chip served as the test food, and a sieve analysis was used to evaluate swallowing threshold and masticatory performance. Ten controls were studied in order to determine corresponding normative scores. Post-surgery results indicate that the extent of mandibular resection and loss of continuity tend to decrease masticatory function. The time required to perform the mastication test, and the number of strokes required to achieve swallowing threshold were increased. Prosthetic rehabilitation did improve masticatory function in some patients. Loss of mandibular continuity may not be an absolute predictor of decreased masticatory function.

Adult↗
PubMed1995

Masseter muscle activity and the hypoglossal nerve.

The effects of severing the hypoglossal nerve and resultant restriction of tongue movement was evaluated for its effect on masticatory jaw movement. Electromyograms of masseter muscles in the feeding rat were recorded 3 days after the nerve severing operation at 1 week intervals. Even after severing the lateral branches of the hypoglossal nerve bilaterally, active-feeding behaviour continued with mastication slightly impaired. After severing the medical branches bilaterally, feeding behaviour was rarely observed, but where eating did take place mastication was impaired with marked disturbance in the masticatory rhythm.

Animals↗
PubMed2005

Condylar resorption during active orthodontic treatment and subsequent therapy: report of a special case dealing with iatrogenic TMD possibly related to orthodontic treatment.

A 28-year-old female underwent orthodontic treatment for approximately 22 months. During the later stages of this treatment, the patient reported right shoulder and neck-muscle pain. In addition, temporomandibular joint disorder (TMD) with a 'clicking' sound during mastication commenced 5 months prior to treatment completion. Specific medication to deal with these symptoms was suggested by medical specialists, as were some stress-relief methods, although the pain still progressed, and subsequent clinical and radiographical examinations were undertaken by another orthodontist. Right mandibular condylar resorption was observed from both the panorex and temporomandibular joint (TMJ) radiographs. No clinical signs of rheumatic disease were observed, although bruxism was noted. Following the termination of the orthodontic treatment by the second practitioner, the patient was treated with splint therapy 1 month subsequent to which, the previous symptoms of pain in the shoulder and neck, and the clicking sound during mastication had subsided. During the 14-month period of splint therapy and follow-up, new bone growth in the right condyle was observed from radiographs.

Adult↗
PubMed2005

Detection of improvement in the masticatory function from old to new removable partial dentures using mixing ability test.

The aim of this study was to determine the sensitivity of the Mixing Ability Test to detect improvement of masticatory function in subjects on transition from old to new removable partial dentures. Thirty-two subjects (seven males, 25 females, mean age 65.0 years) with distal extension partially edentulous area in mandible and/or maxilla participated in the study. The following reasons were presented for replacing the old removable partial dentures with new ones: fracture and/or poor fitness of retainers, extraction of abutment teeth, poor fitness of denture base, severe wear of artificial teeth and request for metal base dentures. Masticatory function with old and new removable partial dentures after an adaptation period (mean 27.4 weeks) was evaluated by the Mixing Ability Test. Subjects were asked to masticate five two-coloured wax cubes with each removable partial denture. Mixing Ability Index was obtained from the colour mixture and shape of the masticated cubes. Wilcoxon signed-rank test was used to test the difference of Mixing Ability Indexes between old and new removable partial dentures. The mixing ability indexes with new removable partial dentures (mean+/- s.d.: 0.70+/- 0.68) was significantly higher (P<0.001) than those with old removable partial dentures (-0.11+/-1.13). The results suggest that the Mixing Ability Test was capable of detecting improvement in masticatory function with new removable partial dentures.

Aged↗
PubMed1998

Masticatory function and its effects on general health.

One of the main goals of dentistry is to preserve a lifelong healthy masticatory function. Recent studies have shown that mastication is of great importance, not only for the intake of food but also for the systemic, mental and physical functions of the body. The purpose of this review is to compile the latest scientific information concerning the relationship between mastication and general health.

Aging↗