An international comparative multicenter study of assessment of dental appearance using computer-aided image manipulation

PURPOSE

The aim of the present investigation was to perform an international multicenter comparison of dental appearance as evaluated by dentists, dental technicians, and nondental subjects.

MATERIALS AND METHODS

The participants were drawn from three groups: 203 dentists, 197 dental technicians and 254 nondental subjects. The methods developed in a previous study in Sweden were applied again in seven centers located in six countries. A questionnaire, accompanied by five sets of computer-manipulated images portraying one man and one woman, was used to prompt and record responses to different aspects of dental appearance and function.

RESULTS

The questionnaire revealed that both the dental appearance and function of teeth were important to most of the participants, but three quarters of the participants did indicate that good dental function was more important that esthetics. More women (30%) than men (18%), however, placed greater importance on appearance. Age or gender did not influence judgments of the computer-manipulated images, although judgments did vary greatly within the three groups and between the centers. Nonetheless, highly colored teeth were preferred more often by nondental subjects than by dentists or dental technicians.

CONCLUSION

Computer-aided image manipulation shows promise as a method for investigating the significance of dental-related beliefs, especially those relating to esthetics, in different population groups. The evaluation of dental appearance and function in this study indicated that dental function is held in greater regard, and that the significance of dental appearance varies widely among dentists, dental technicians, and nondental subjects.

[Orbito-cranial reconstruction and unilateral optic canal release in a patient with left fronto-orbital fibrous dysplasia: a case report]

A surgical case of monostotic fibrous dysplasia of the left frontal and sphenoidal bone in a 14-year-old girl is described. This girl was admitted to our hospital in March, 1992, with a chief complaint of facial deformity and asymmetry due to a painless and progressive bony bulging over the left fronto-orbital region. But she denied any symptoms such as proptosis, diplopia, optic atrophy and visual loss. Other data found on neurological examination and laboratory tests were normal. In addition, she had no history of skin lesions, precocious puberty or other endocrine abnormalities. Plain craniogram showed remarkable thickening of the left frontal bone and of the anterior cranial fossa of the sphenoidal bone with irregular stenosis of the left optic canal. CT scan showed the diffuse enlargement of the affected bone and involvement of the paranasal sinuses. Angiography revealed no positive findings. On December 10, 1992, orbito-cranial reconstruction and unilateral optic canal release were performed using an extradural approach through a left fronto-temporal craniectomy. Histological findings confirmed the lesion to be typical fibrous dysplasia. She recovered completely one month after the operation, but she suffered transient blurred vision, diplopia and left ptosis. Most of the decreased vision caused by fibrous dysplasia cannot be reversed after surgical treatment. So, if optic canal stenosis is evident, even when visual loss is not clear, release of the optic canal stenosis should be done as early as possible in association with experienced neurosurgeons and with meticulous dissection.

Clinical applications and basic studies of laser in dentistry and oral surgery

In our clinical use of lasers, mainly CO2 laser for oral surgery, we found that the laser had many advantages over an electrome and the laser improved the local control rate for malignant tumors. Low-power laser has been used to treat hypersensitive dentin, to relieve pain caused by neurotic disease around mouth, and to promote the healing of those diseases. The results obtained from the clinical applications showed that irradiation of the hypersensitive dentin with low-power laser was significantly effective in desensitization. An in vitro study showed no effects of diode or He-Ne laser irradiation on the growth of cells, but showed changes in the initial cell adhesion rate. He-Ne laser irradiation to the wound in the skin of hamsters caused to change the activities of the types I and III collagenase. This fact suggest that laser irradiation acted to promote the healing of wound.

Mandibular alveolar ridge extension method using a surgical splint with porous hydroxyapatite (HAP) particles

The mandibular alveolar ridge extension method is a surgical technique to extend the alveolar ridge up to the required level. Using a surgical splint prepared to meet the clinical requirements establishes the desirable alveolar ridge extension with porous hydroxyapatite (HAP) particles. Before the operation, a working cast of the extremely resorpted mandibular alveolar ridge is remodeled into its desired shape with paraffin wax, and the extended surgical splint is cured by clear acrylic resin. After subperiosteal tunnel dissection, the surgical splint is fixed to the mandible with circummandibular ligatures; then the HAP particles are injected into the tunnel. After healing, a treatment denture is cured between the artificial dentition and the surgical splint with self curing resin. In this method, the HAP particles are injected into the subperiosteal tunnel that is created between the surface of alveolar bone and the periosteum covered by the surgical splint; the migration of HAP particles completes the extension of the alveoral ridge.

Vitamin B12 treatment for sleep-wake rhythm disorders

Vitamin B12 (VB12) was administered to two patients suffering for many years from different sleep-wake rhythm disorders. One patient was a 15-year-old blind girl suffering from a free-running sleep-wake rhythm (hypernychthemeral syndrome) with a period of about 25 h. In spite of repeated trials to entrain her sleep-wake cycle to the environmental 24-h rhythm, her free-running rhythm persisted for about 13 years. When she was 14 years old, administration of VB12 per os was started at the daily dose of 1.5 mg t.i.d. Shortly thereafter, her sleep-wake rhythm was entrained to the environmental 24-h rhythm, and her 24-h sleep-wake rhythm was maintained while she was on the medication. Within 2 months of the withholding of VB12, her free-running sleep-wake rhythm reappeared. The VB12 level in the serum was within the normal range both before and after treatment. The other patient was a 55-year-old man suffering from delayed sleep phase syndrome since 18 years of age. After administration of VB12 at the daily doses of 1.5 mg, his sleep-wake rhythm disorder was improved. The good therapeutic effect lasted for more than 6 months while he was on the medication.

[Transplantation of embryonic medulla oblongata into cerebella of adult rats]

Pieces of medulla oblongata anlagen were dissected free from embryonic 13-20 day (E 13 to E 20) rat brain, and these were transplanted into the cerebellar vermis of adult rats (Fischer 344). After grafting, host animals survived for 4-9 months. Cytoarchitectonic organization of the graft and the relationship between host and graft were analyzed light microscopically in 34 animals using the Nissl and silver impregnation methods. Fine structures of the graft were analyzed in 4 animals using electron microscope. Grafts from E 13-14 donor tissue showed the highest survival rate (90%), which decreased as the donor embryonic age increased (i.e., E 15-16: 33%, E 17-20: 15%). In the surviving grafts, small (5-10 microns diameter), medium-sized (10-20 microns) and large (20-30 microns) neurons, whose cytoplasmic organelles appeared normal, were observed. Bundles of myelinated fibers traversed in every direction and neurons were often clustered, indicating characteristic features of the medulla oblongata. Electron microscopically, various types of synaptic formations were also observed. Degenerative profiles of nerve-fiber endings, containing dense bodies and lysosomal figures, were also seen. The degeneration seemed to be caused by the failure of their establishing connections with their proper targets in the host. In both the host tissue and the graft-host interface, neuronal processes apparently derived from the graft were frequently observed. Some axonal processes contained large-cored vesicles, and some dendritic processes were enlarged at their stalks and tips. Aberrant axon terminals of unmyelinated fibers in the host medullary layer were considered to be the graft origin. These fibers were always accompanied by prominent glial proliferation. There was no indication of forming myelinated fiber bundles that entered the host cerebellum from the donor tissue, although the former was the target of the latter. Cell bodies of host granule cells and oligodendroglia in the graft-host interface were surrounded by processes of oligodendroglia, forming thin myelin lamellae. The present study showed that unmyelinated fibers from the graft could enter the host cerebellum non-specifically accompanied by glial proliferation, whereas myelinated fibers could hardly penetrate into the host crossing the glial scar.

[Ultrastructural study of the growth pattern in an experimental meningeal gliomatosis model]

We tried to examine the growth pattern of meningeal gliomatosis (MG) by using an experimental MG model. C6 rat glioma cells (3 X 10(5)/0.1 ml) were injected percutaneously into the cisterna magna of rats. Seven days after inoculation, the brains and spinal cords were removed and processed for morphological observation. Light microscopic findings showed that numerous tumor cells had invaded the spinal cord parenchyma directly and/or via the Virchow-Robin spaces. In contrast, a small amount of tumor cells had spread horizontally on the surface of the spinal cord. By transmission electron microscopy, discontinuity of the basal lamina (of the marginal glia) was found, and some tumor cells were found to have protruded their processes into the spinal cord parenchyma. A basal lamina-like granular material was observed in the vicinity of these areas, indicating the breakdown of the basal lamina. Scanning electron microscopic findings further supported the speculation concerning the penetration of the pia mater by tumor cells through the small pores which had blunt margins. From these ultrastructural observations, we speculated that some chemical membranolytic factors might play an important role in MG.

Grafted granule and Purkinje cells can migrate into the mature cerebellum of normal adult rats

Cerebellar primordia of different ages (embryonic days of 14 to 20) were transplanted into cerebella of normal syngeneic adult rats (Fischer 344). After 1-12 months (mostly 5-6 months), the host brains were examined by light and electron microscopy. In about 80% of our successful experiments, grafted Purkinje and/or granule cells migrated into the host molecular layer. Some granule cells migrated down along host Bergmann glia, reminiscent of their normal developmental migration route. Other granule cells migrated along astroglial processes that ensheathed capillary walls. Some grafted Purkinje cells were also located ectopically in the host molecular layer. They were identified as graft origins autoradiographically. This migration seemed to be encouraged under conditions where the subjacent host Purkinje cells had been lost. Where the grafted Purkinje cells were located on top of the host molecular layer, their primary dendrites faced vertically downwards into the host molecular layer. However, the position of the apical poles of migrated Purkinje cell bodies in the deeper aspect of the molecular layer varied considerably, suggesting that the orientation of the Purkinje cell dendrites is probably determined by the availability of afferent fibers. Thus, the present study has demonstrated that Purkinje and granule cells can migrate from embryonic cerebellar grafts into the molecular layer of the normal, adult host rat cerebellum.

Four congenitally blind children with circadian sleep-wake rhythm disorder

Four congenitally blind children aged 4-12 years, with severe or moderate mental retardation, were chronobiologically studied. Three of them showed a free-running rhythm of sleep-wake, and the fourth showed an irregular sleep-wake rhythm. To entrain their sleep-wake rhythm to a 24-h rhythm, several trials based on chronotherapy were performed. The free-running rhythms in the three children were considered their own endogenous rhythms, revealed through some disorder in the mechanism synchronizing the endogenous rhythm to the normal 24-h environmental rhythm. The irregular sleep-wake rhythm in the fourth child may have been the result of immaturity or failure of the pacemaker of the circadian rhythm. Because of their severe mental retardation, all the children were lacking in social time cues, which are the most potent "Zeitgebers" for human biological clocks.

[A case of convexity meningioma associated with chronic subdural hematoma]

There are 5 reported cases of meningioma complicated by chronic subdural hematoma so far as we reviewed. Considering frequency of occurrence, association of meningioma and chronic subdural hematoma is very rare. Recently, we experienced with a case of convexity menigioma complicated by chronic subdural hematoma. The patient was a 61-year-old woman who complained of headache and numbness of the left hand. She received hysteromyomectomy 28 years before but had no past history of trauma of the head. She suffered from frequent profound pain in both orbits for one year, and she consulted a neighboring practitioner due to occurrence of numbness of the left hand and malaise. Then, CT scan revealed abnormalities, so that she was referred to our center. On admission, neurological oxamination revealed no abnormalities but plain X-ray film of the skull showed a round destruction in the right parieral bone. CT scan showed a round high density area of 3 cm in diameter in the right parietal region, this is markedly enhanced with contrast media. There is a crescent-shaped low density area extending forward from the high density area. The body of the right lateral ventricle is totally collapsed. Selective arteriography of the right external carotid revealed tumor stain in the parietal region. Therefore, under the diagnosis of association of chronic subdural hematoma and convexity meningioma, craniotomy of the right frontal, parietal and temporal regions was carried out and a meningioma of 10 g, and a subdural hematoma with its capsule touching the maningioma were entirely extirpated.(ABSTRACT TRUNCATED AT 250 WORDS)

[A rare case of subarachnoideal pneumocephalus after ear douche therapy]

No detailed reports on pneumocephalus caused by any factors other than head trauma, and their courses accompanied with this disease have been so far available. We recently experienced a case of pneumocephalus complicated with severe clouding of consciousness, ocular deviation, and unilateral spatial neglect with the results being reported hereinafter. A 54-year-old man had often received ear douche therapy due to chronic sinusitis and tubal obstruction about 3 years before without any history of head trauma. On Jan. 6, 1984, sudden clouding of consciousness accompanying stiffness of the left arm occurred immediately after ear douche, and then he was transferred to our center. At admission, semicomatose, bilateral ocular deviation to the right, and left hemiparesis were observed. Plain skull X-ray films showed a retention of air in the frontal and temporal regions, while CT scan revealed air retention on the bilateral frontal region, bilateral temporal tip and suprasellar cistern. However, no abnormal findings were detected in the brain. Consciousness and hemiparesis recovered on the next day of hospitalization, however, the left hemispatial neglect still remained. This symptom was still observed on the 3rd day but disappeared by the 4th day of hospitalization. For clarifying its cause, cerebral angiography, CT scan and electroencephalography were then performed. CT scan revealed no anomalies in the brain, while cerebral angiography showed a cerebral circulation pattern in favor of the right internal carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)