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At least 19 recordsLinked to original sources

[Class II--vertical dimension].

The vertical dimension and its implication in the etiology of the class II are described. This dimension is analysed at the level of the cranial base, the maxillary and mandibular bones and alveolar processes. Then, the facial architecture as a whole is considered and particularly the key position of the upper molar. The dorsal and low position of these teeth in the hyperdivergent cases is fundamentally different from the one they occupy in the hypodivergent cases. The therapeutic approach is completely different in both cases and is illustrated by means of three deep overbite and three open bite cases.

Alveolar Process

[Review of the treatment of decreased vertical dimension].

The decreasing of vertical dimension, specially in extremely cases (more than three clinical standard deviations) is a border problem between orthopedics, orthodontics, prosthetics and surgery. The authors reviewed the treatments possibilities proposed by the different specialties.

Adult

Vertical dimension: a dynamic concept based on facial form and oropharyngeal function.

Craniofacial vertical dimension is a more accurate measure of facial proportion than mere measurement of the mid and lower part of the face. Craniomaxillary dimension is skeletally determined, whereas facial height of the lower part of the face is partly dependent on the vertical dimension of occlusion. Alterations in the vertical dimension of occlusion can dramatically affect the esthetics of the soft facial tissue. The "Golden Proportion" quantitatively defines ideal measured relationships and encourages a scientific appreciation of beauty. Faces with deficiencies in lower facial balance (brachyfacial) often exhibit insufficient height of the occlusal plane. The scientific literature has suggested a pliability of skeletal muscle allowing for physiologic variance in vertical facial height. Temporomandibular joint compliance is demonstrated with elevations in resting muscle length. Facial balance and location of the occlusal planes are the primary determinants for establishing an appropriate vertical dimension of occlusion.

Electromyography

An acoustically investigated case of phonetic change in higher vertical dimension.

This report presents the phonetic changes of a patient whose occlusal vertical dimension is extended. His chief complaint is esthetic restoration of his anterior teeth, but his occlusal vertical dimension is abnormally shortened by long-time attrition. Therefore we extended his occlusal vertical dimension, and reconstructed his occlusion, and carried out acoustic observations.

Aged

Relationship of occlusal vertical dimension to the health of the masticatory system.

Changes in occlusal vertical dimension have been claimed to cause masticatory system disorders. Early articles on this subject were mainly limited to clinical case reports, and the more recent clinical studies have been flawed by the lack of control groups, blind evaluation, and by poor definition of criteria for evaluating the health of the masticatory system. Research with humans and animals has shown that if increases in occlusal vertical dimension are not extreme and the appliance used covers most of the dentition, there is a good possibility of adaptation. Current scientific knowledge does not support the hypothesis that moderate changes in occlusal vertical dimension are detrimental to the masticatory system.

Animals

A preliminary investigation into the effect of increased occlusal vertical dimension on mandibular movement during speech.

Current methods of determining whether a patient will accommodate to an increased occlusal vertical dimension rely on a largely subjective assessment of the mandibular rest position and capacity to adapt whilst wearing a temporary appliance. The purpose of this preliminary study was to establish if mandibular movement during speech may provide an objective criterion in the assessment of adaptation to increases in occlusal vertical dimension. The closest speaking space, measured as the vertical distance between an incisor point and centric occlusion, as determined during pronunciation of sibilant speech sounds was chosen to depict mandibular movement. The closest speaking space was determined using a Sirognathograph for six young adult subjects and varied from a mean of 1.0 to 3.3 mm. An acrylic splint covering the entire occlusal surface of the lower arch, designed to increase the occlusal vertical dimension by 4 mm in the incisor region, was then cemented on each subject's mandibular arch. The closest speaking space was again determined after 5 days continuous wear of the splint and the mean values found to have decreased to a range of 0.0-1.0 mm. The differences between the mean values for the closest speaking space for each subject before and after splint wear were statistically significant. It was postulated that this method may lead towards an objective basis for deciding if patients will adapt to an increase in occlusal vertical dimension.

Adaptation, Physiological

Measuring pressures under maxillary complete dentures during swallowing at various occlusal vertical dimensions. Part II: Swallowing pressures.

The swallowing pressures of seven edentulous patients were measured at seven different occlusal vertical dimensions. In addition, the projection surfaces of the maxillary dentures were measured and the forces on the maxillary denture-bearing surfaces were calculated. The swallowing pressures were measured from the maxillary denture base-mucosal surface interface by means of a "closed" hydraulic system described in Part I. The mean values of swallowing pressures increased from 7.95 +/- 2.25 to 10.18 +/- 3.42 kPa as the occlusal vertical dimension increased, and then decreased to 8.38 +/- 3.55 kPa at the highest occlusal vertical dimension. The results of a two-way analysis of variance showed significant differences of swallowing pressures between patients (p less than 0.001) and between different occlusal vertical dimensions (p less than 0.001). The projection surfaces of maxillary denture bases were measured and ranged from 21.65 to 27.78 cm2. The forces exerted on these surfaces during swallowing were also calculated and ranged from 12.5 to 47.7 N.

Adult

Occlusal vertical dimension changes in visible light-cured resin.

On a twenty standard, identical edentulous upper and lower casts, an identical upper and lower waxed-up sets of dentures were constructed with same vertical dimension of occlusion. These waxed up dentures were divided into two equal groups. For group I, the dentures sets were processed in compression molding heat-cured acrylic resin denture base material. For group II, the denture sets were processed in visible light-cured denture base material. After processing the vertical dimension of occlusion was measured for every denture set in both groups. It was found that there was an increase in the vertical dimension of occlusion on group I and a decrease in the vertical dimension of occlusion in group II. Regardless of the direction of the changes in the vertical dimension of occlusion, it was found that there was a significant difference between the dimensional changes in both groups and the dimensional changes in the denture bases of group I was more than group II by 54.5%.

Acrylic Resins

The relationship of vertical dimension of atypical swallowing with complete dentures.

A number of subjects were studied cineflourographically during swallowing, and their vertical dimensions of occlusion were clinically evaluated. The subjects who had reduced vertical dimensions of occlusion were older than those with normal vertical dimensions, their dentures were older, their total years with complete dentures were more, and the tendency to swallow without opposing tooth contact was greater. The cumulative evidence indicates that such aberrant muscle activity might contribute to the regressive changes found in complete denture wearers.

Aged

Rest vertical dimension determined by electromyography with biofeedback as compared to conventional methods.

This study was undertaken to determine if electromyography with biofeedback can be utilized to produce a more reliable determination of rest vertical dimension than conventional methods such as phonetics and swallowing. It was found that: 1. Electromyography with biofeedback appeared to produce a more consistently reliable determination of rest vertical dimension than conventional methods when used with edentulous subjects. 2. Determinations of rest vertical dimension by individual dentists using phonetics and swallowing had wide variations in two of the five patients in a range of up to 6 mm. An error of this magnitude could easily cause an intrusion upon the interocclusal distance and resultant failure of treatment. Since this study was limited to five patients, a more expanded study is necessary to determine the validity of electromyography vs. conventional methods for determining rest vertical dimension. Both methods have questionable aspects in relation to the time of day, patient's understanding of each technique, and past dental history. However, the most critical problem of the electromyographic technique is the feasibility of its use in a private practice in light of the excessive cost of the required equipment.

Biofeedback, Psychology

Preservation of occlusal vertical dimension in overdentures.

The preextraction record is used to reestablish the occlusal vertical dimension in immediate and in later overdentures. A colored dot on the denture can be used to verify the occlusal vertical dimension after the dentures have been inserted.

Dental Records

An experimental study of increased vertical dimension in the growing face.

Five juvenile rhesus monkeys were used in an experiment designed to study the structural adaptations in the craniofacial complex that resulted from increases in vertical dimension. The bite was opened 2,3,10, or 15 mm. by means of cast bite splints cemented on the maxillary arch. Adaptations were monitored in these animals by means of serial cephalometric radiography with metallic implants. The results of this study indicate that any change in the vertical dimension of the face results in specific structural adaptations throughout the craniofacial complex. The most significant adaptation occurred in the maxillary region, in which the normal downward displacement of this region was decrease and the anterior displacement was increased. Adaptation were less evident in the mandible, except in those animals in which a severe bite opening was produced; resorption in the region of the gonial angle was evident. Dentitional adaptations were of secondary importance. This study demonstrates that the maxillary complex is a very plastic structure which responds to changes in bite opening and altered muscle length. The clinician should be aware of the changes that result from various alterations of vertical dimension to make sure that these changes are not antagonistic to his over-all treatment goal. He may also take advantage of these changes when designing treatment strategies for certain clinical cases.

Animals

A new method for positioning the maxillary anterior arch, orienting the occlusal plane, and determining the vertical dimension of occlusion.

A new method for positioning the maxillary anterior arch, orienting the occlusal plane, and establishing the vertical dimension of occlusion in edentulous patients is described. The procedure uses a newly developed registration pin assembly that is fixed to the maxillary acrylic resin baseplate. The vertical dimension of occlusion is determined by having the patient swallow. This approach eliminates the tedious and time-consuming process of trimming the occlusion wax rims. The accuracy of the new method is currently being evaluated.

Deglutition

[Influences of changing vertical dimension, occlusal contacts of bite plane and body position on masticatory muscle activities].

The Bite plane therapy has been accepted to be useful for treatment of the patients with the stomatognathic dysfunction. The purpose of this study is to make clear the influences of changing the vertical dimension and occlusal contacts of the bite plane on masticatory muscle activities in order to improve the bite plane therapy. The full arch bite plane with an interincisal distance of 5 mm was fabricated for each one of 30 subjects without stomatognathic dysfunction. The EMG activities were recorded from the anterior part of the temporal muscles, the masseter muscles and the anterior belly of the digastric muscles bilaterally while the subject exerted tapping and maximal voluntary clenching in a postural position. Four kinds of experiments were performed as follows. In Exp. 1, integrated EMG activities of each muscle were compared with and without the bite plane. In Exp. 2, the influences of changing the vertical dimension of the bite plane (2.5 mm, 5 mm and 7.5 mm) were tested in 17 subjects. In Exp. 3, the influences of changing the location of occlusal contacts of the bite plane were studied in 12 subjects. In Exp. 4, the influence of changing the body positions on EMG activities and mandibular positions was compared in 30 subjects between the sitting and supine positions. Furthermore, the influence of the same factor was compared with and without the bite plane which was adjusted in each position. The results were summarized as follows: 1. Wearing the bite plane mainly reduced activities of the temporal muscles. 2. The bite plane with an interincisal distance of 5 mm was most effective in reducing activities of the temporal muscles. 3. Wearing the bite plane with anterior occlusal contacts reduced activities of the elevator muscles significantly. 4. Significant differences in activities of the temporal and digastric muscles were recognized between the two body positions when the bite plane was not applied. However, no significant difference was recognized when the bite plane was inserted. Furthermore, those differences were correlated with the difference in the antero-posterior mandibular displacement between the two body positions while the subject tapped the teeth. These results suggest the possibility to control masticatory muscle activities by applying the bite plane with the proper vertical dimension and occlusal contacts. In addition, it is necessary to take a suitable body position for the patient who has a difference in the mandibular displacement between the sitting and supine positions when applying the bite plane.

Dental Occlusion

Changes in vertical dimension of occlusion in conventional and microwave processing of complete dentures.

An investigation was made to compare the increase in vertical dimension of occlusion in complete dentures after processing with conventional and microwave procedures. Lucitone-characterized denture base material was used for 15 sets of complete dentures cured conventionally. Justi-characterized acrylic resin and microliquid were used for 15 sets of complete dentures cured by the microwave procedure. The results of the study showed increases in vertical dimension of occlusion in both methods under 1 mm, which is considered technically acceptable. However, a statistically significant larger increase was present in the microwave technique.

Acrylic Resins

Influence of lower lip support on recording of vertical dimension in edentulous patients.

The purpose of this investigation was to assess the influence of differences in design of the occlusion rim on recorded vertical dimension in complete denture therapy. Edentulous patients were studied with an opto-electronic method when the vertical dimension of rest was established with and without labial support of the occlusion rim. As no significant differences were found, the results did not support the hypothesis that the contour of the lip support will influence the recorded physiological rest position. However, a significant difference between intra and extraoral placement of the point of measurement was found.

Aged

Vertical dimension increases in the adult rhesus monkey: a pilot study.

Tooth impaction, increased muscle activity, and histologic changes in the bone of the temporomandibular joint have been reported following attempts to increase the vertical dimension of occlusion. The purpose of this research was to study the effects of increases in the vertical dimension of occlusion on bone density at five levels of the mandible in the adult rhesus monkey, and to assess dentoalveolar changes by lateral cephalometric radiographs and mounted diagnostic casts. Mandibular cobalt chromium splints measuring 3 mm in height at the first molar, providing even occlusal contact to the maxillary anterior and posterior teeth, were cemented in place on two monkeys. Five similar monkeys without splints were used as controls. Computed tomograms were completed to evaluate bone density bilaterally at five levels of the mandible after 3 months of splint wear. Pretreatment and posttreatment lateral cephalometric radiographs and mounted diagnostic casts were completed to assess tooth impaction. Periodontal ligament (PDL) thickening and mobility of molars and premolars were evaluated before splint placement and after splint removal. There was no statistically significant difference in the bone density levels of the animals with splints compared with the controls. Minimal dentoalveolar changes were observed.

Animals

Regressive formula to determine vertical dimension in the edentulous.

The distances between the cephalometric points of 380 patients with complete natural dental arches were measured. A correlation between the bizygomatic, nasion-subnasal and subnasal-gnathion distances and the vertical dimension was established and a mathematical formula was derived to enable determination of both the physiologic rest position and vertical dimension at centric occlusion in edentulous patients.

Cephalometry