In order to from the certain speech sounds, the tongue touches various portions of the teeth, the alveolar ridge, and the palate, and should these structures be replaced or covered by a prosthetic appliance, proprioceptive feedback may be altered, so that the speech articulation is disturbed. Thus, a denture that has been constructed without taking the articulatory movements of the tongue into consideration can adversely affect the production of the proper sounds. In this regard, a method that can determine not only the contact patterns of the tongue with the palate but also with the teeth would be of great benefit in designing the palatal contour and the positioning of the artificial teeth of a pros-thesis.
For this purpose, static palatography has been used to identify contact patterns by means of palatograms of tongue-to-palate and tongue-to-teeth movements of 6 denturous Chinese adults, 4 men and 2 women, during the production of the following Chinese sounds : [s, f, tf, k, t, n, r, and 1].
To create the palatograms, a black vinyl sheet, vacuum-molded to cover the palate and the occulusal surface of the maxillary teeth and coated with white powder of alginate impression material, was inserted into the mouth of each tested subject. Each subject then was asked to pronounce a requested sound, and as the sound was produced, the movements of the tongue Wet the powdered vinyl surface, thereby providing a palatogram of that sound.
On taking 5 palatograms of each of the sounds, palatograms of the same sound were compiled by an image processor and the contact areas that were common to 60% (3/5) or more of the pronunciations were extracted. In this way the outlines of each subject's palatograms were averaged and converted into a standardized dental arch form, with the gray scale of each image reversed and reduced, and added to the patterns of the same sound pronounced by all the other tested subjects. Thus, palatograms that showed differing grey scale levels were compiled, based on the frequency of overlapping, and from this compilation, tongue contact areas that were common to 67% (4/6) or more of the subjects were extracted.
The results of this extraction have indicated that the tongue-to-teeth contact area of each sound differed, but that the variances were confined to the cervical half of the lingual surface of the incisors and the lingual cusps of the molars. On comparing the contact patterns of these Chinese sounds with the contact patterns of equivalent Japanese sounds from 30 previously tested Japanese subjects, it was found that the contact patterns of many sounds were quiet similar. However, a difference was noted between the Chinese and Japanese palatograms for the following sounds : [r, 1, and tf]

View full abstract

Mineralized bacillus-shaped deposits showing numerous bacterial molds on the surfaces were found in deep subgingival calculus with scanning electron microscopy, after the fractured surfaces were treated with NaOCl. Such structures may be derived from filamentous microorganisms attached with a large number of rod-shaped bacteria showing a 'bristle-brush' arrangement in subgingival plaque; namely, the filaments mineralized intracellularly, while the unmineralized rods dissolved with NaOCl treatment.

View full abstract

By using scanning electron microscopy, the successional transformation of plate-shaped octacalcium phosphate (OCP) to hexahedral whitlockite (WH) was observed in human dental calculus. Such a transformation indicates that some of the WH crystals are epitaxially formed on OCP crystals.

View full abstract

This study was undertaken to establish a method for evaluating speech disorders by determining the constancy of articulatory activity during the repeated pronunciation of plosives. Tested and compared were the speech patterns of 10 normal controls and one cleft palate patient tested at different stages, i.e., before prosthetic treatment (stage A), while wearing a temporary overdenture (stage B), at insertion of the final prosthesis (stage C), and at six months after insertion of the final prosthesis (stage D).
All tested subjects were instructed to repeatedly pronounce /pa/, /ta/, /ka/ and /pataka/ as rapidly as possible until running out of breath. These vocal patterns then were analyzed by a sound spectrograph (DSP Sona-Graph, Model 5500, Kay Co. USA) and studied on an expanded time-wave CRT display to measure three items : the characteristics of the spectrographic pattern, the number of the repetitions, and the duration of the sound. The duration of the consonants and vowels were measured, as well as the intervals between each syllable. Further, each consonant was divided into two parts : the duration of the plosive spike, and the damping of this spike to the beginning of the next sound.
Results revealed that the sound patterns of the cleft palate subject during stage A varied greatly from those of the normal subjects, but that these differences gradually diminished during stages B and C and became remarkably similar at stage D, almost resembling the patterns of the normal controls.
While the number of repetitions that the cleft palate patient was capable of was limited during stage A, the ability to repeat plosives increased as the prosthetic treatment progressed. Sim-ilarly, the duration of the consonant and the plosive spike of the /k/ of the patient at stage A was much longer than that of the controls, but this difference also decreased.
Based on the results of this study, it was concluded that to improve the speaking capability of cleft palate patients, the designed dental prosthesis must not only achieve naso-pharyngeal or naso-oral closure but also must include a compatible occlusal vertical dimension and a proper maxillary dental arch.

View full abstract

Up to now there have been numerous papers concerning the similarity between facial form and maxillary central incisor tooth form.
This study attempts to adapt the Fourier series to examine the similarity between facial form and maxillary central incisor tooth form. Data used in this study was obtained from facial forms and plaster casts of maxillary central incisor tooth forms of 40 Filipino males and 70 females. A modified version of Pöch's ten-category pattern was used as a categorization standard. A value of less than 0.3 calculated using the Fourier series was used as the standard for similarity between facial form and maxillary central incisor tooth form.
When facial forms were categorized according to the similarity standard, the most frequent category pattern for both males and females was an ellipsoid form. Oval was the most common form of the maxillary central incisor in both the right and left sides for males, while a rhomboid form on the right and a round form on the left were the most common in females. When combinations of facial forms and maxillary central incisor forms were categorized, groups appearing in the same category pattern amounted to 12 for both sides in males and 20 for both sides in females.
The similarity rate between facial form and maxillary central incisor form was 71. 5% for the right and 71.43% on the left in males, and 78.95% on the right and 75. 81% on the left in females. Based on this information, we can say that, while facial form and maxillary central incisor form do not necessarily fall into the same category patterns, they display a similarity rate of approximately 70%.

View full abstract

A rare case of central neurilemmoma arising in the mandible is reported. The tumor revealed unusual rapid growth in 2 years. To obtain pathological diagnosis of this tumor, an immunohistochemical technique using antibodies against myelin basic protein and S-100 protein was applied to the biopsy specimen. The immunohistochemical examination revealed the overgrowth of nerve sheath cells. The macroscopic and histological examination of the surgical material confirmed that the tumor was a neurilemmoma. In this report we discuss the usefulness of the immunohistochemical examination in diagnosing neurogenic tumor in a biopsy specimen.

View full abstract