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PubMedDate not supplied

Postural control in order to prevent chronic locomotor injuries in top level athletes.

Chronic injuries of the locomotor apparatus represent the main cause of drop-out among top level gymnasts. The aim of the present paper was to verify whether the postural control, investigated by using an integrated approach and accordingly optimized, could be an effective tool for the secondary prevention of training-related disorders of the locomotor apparatus, in a cohort of 20 young female athletes practicing rythmic gymnastic at top level. After a preliminary medical consultation all the subjects underwent a static and dynamic baropodometric test, an ophtalmological and a dental screening. Then athletes were given prescriptions based upon the results of the above named examination. After 6 months, symptoms were completely disappeared in 80% and remarkably improved in 20%, and at baropodometric test, the contact duration as well as the contact surface, the max and mean contact pressure were significantly increased in all the athletes. Our data show that the proposed integrated approach is actually an effective tool for the secondary prevention of training related disorders of the locomotor apparatus.

Adolescent↗
PubMed1993

Orthodontic tooth movement into edentulous areas with reduced bone height. An experimental study in the dog.

The present study was performed in order to test the hypothesis that the height of supporting bone and connective tissue attachment will be maintained around teeth bodily moved into areas of reduced bone height. During a pre-experimental period, areas with markedly reduced bone height were produced in the mandible of 4 beagle dogs through extraction of the 4th premolars and subsequent surgical reduction of the bone height in the extracted sites to a level corresponding to half the root length of the 3rd premolar. Following healing, one of the third premolars was bodily moved in a distal direction into the area of reduced bone height, while the contralateral premolar served as a non-moved control. After 6 months of active tooth movement, the teeth were retained in their new position for a further 2 months before biopsies of test and control tooth sites were sampled. Radiographic evaluation showed that a bodily movement had been achieved with no or only minimal vertical displacement of the teeth. The histological analysis revealed that none of the teeth, orthodontically moved or not, had experienced loss of connective tissue attachment. Although a greater distance between the cemento-enamel junction and the bone crest was found on the pressure side of the orthodontically moved test teeth in comparison to the contralateral, non-moved control teeth, the bone level at all test teeth was more coronally positioned than the original, reduced bone level in the area into which the test teeth had been moved. Hence, these findings indicate that a tooth with a normal height of periodontal support can be orthodontically moved into an area of markedly reduced bone height with maintained height of the supporting apparatus.

Alveolar Bone Loss↗
PubMed2004

Development of amygdaloid kindling in histidine decarboxylase-deficient and histamine H1 receptor-deficient mice.

PURPOSE: This study attempted to clarify the role of histamine or histamine H1 receptors in the development of amygdaloid kindling by using histidine decarboxylase (HDC)-deficient and histamine H1 receptor (H1R)-deficient mice. METHODS: Under pentobarbital anesthesia, mice were fixed to a stereotaxic apparatus, and bipolar electrodes were implanted into the right amygdala. Electrodes were connected to a miniature receptacle, which was embedded in the skull with dental cement. A bipolar electroencephalogram was recorded; bipolar stimulation of the amygdala was applied every day with a constant-current stimulator and continued until a generalized convulsion was obtained. RESULTS: The development of amygdaloid kindling in HDC-deficient and H1R-deficient mice was significantly accelerated compared with that in their respective wild-type mice. In addition, the afterdischarge (AD) duration and generalized seizure duration in HDC-deficient and H1R-deficient mice were prolonged. Intraperitoneal injection of histidine resulted in an inhibition of amygdaloid kindled seizures in wild-type mice at doses that caused an increase in the histamine contents of the brain. However, no significant effect was observed with histidine in H1R-deficient mice at the same dose. CONCLUSIONS: These findings suggest that histaminergic mechanisms through H1 receptors play a crucial role not only in amygdaloid kindled seizures but also in the development of amygdaloid kindling.

Amygdala↗
PubMed2002

Strain relaxation of fibroblasts in the marginal periodontium is the common trigger for alveolar bone resorption: a novel hypothesis.

In summary, the present commentary proposes a hypothesis that alveolar bone remodeling and bone loss in periodontitis, periodontal surgery, and in orthodontic tooth movement is triggered by a common "strain relaxation" signaling pathway of gingival and periodontal fibroblasts. The abrupt splitting, degradation, or relaxation of collagen fibers in the marginal periodontium produces a "strain relaxation" signal in the local fibroblasts which reside on these fibers, activating an ECM-integrin-cytoskeleton pathway. A cascade of cellular reactions which lead to osteoclastic bone resorption starting on the inner aspect (periodontal) of the alveolar bone then persists. A novel therapeutic approach is suggested here by using locally delivered drugs intervening in the cell contractile apparatus.

Alveolar Bone Loss↗
PubMed1989

[Clinical consideration for the bridge pontic with the removable plate applying SmCo5 magnet and ferromagnetic alloy].

SmCo5 magnets and ferromagnetic alloy, which were recently developed, have been used to the removable prosthesis, but are not used to the fixed one. We have applied them as a retainer to the bridge pontic with the removable plate. This pontic have following advantage: 1. It is easy to clean and to alter the pontic lower area attached to the alveolar tissue. 2. It is a simple apparatus. Here we propound 2 typical cases with fine result.

Dental Alloys↗
PubMed1984

Intraligamentary anesthesia--a histological study.

Intraligamentary dental anesthesia is considered to be an efficient and clinically safe anesthetic technique, and as a result, is widely used. The present study evaluates histologically any possible damage to the periodontal apparatus, in baboon monkeys. The damage induced by the injection needle and/or the anesthetic solution, which was injected under high pressure, was localized, minor and reversible. In most of the specimens, all signs of damage disappeared within 8 days following injection. In others, some granulation tissue was evident in the lamina propria 15 days following injection. However, no bone or cemental damage was observed.

Anesthesia, Dental↗
PubMed1994

Hg emission from dental amalgam as related to the amount of Sn in the Ag-Hg (gamma 1) phase.

Previous studies have shown that: (1) different dental amalgams emit different amounts of Hg vapor after surface films have been removed by abrasion (Boyer, 1988); (2) Sn oxide may be the predominant factor in these surface films that inhibit Hg vapor loss (Okabe et al., 1989); and (3) Sn in the Ag-Hg (gamma 1) phase may influence the vapor pressure of gamma 1 (Reynolds, 1974). The purpose of this study was to explore the relationship between Hg vapor emission and the Sn content of the Ag-Hg (gamma 1) phase in dental amalgam. Eleven commercial amalgams were selected whose gamma 1 phases contain different amounts of Sn. Amalgam specimens were ground on 600-grit carborundum paper and immediately placed into an apparatus designed around a gold film Hg vapor detector. Hg vapor loss in air over a 30-minute period was determined, and the log10 Hg loss/volume fraction gamma 1 was plotted vs. the Sn content of the gamma 1 phase for the 11 test amalgams. A linear regression of these data, showing that of the higher the Sn content in gamma 1, the lower the Hg vapor loss, produced a highly significant R2 = 0.94 (p < 0.001). To examine for differences in vapor pressure among alloys, we eliminated the oxidation effect by conducting these same tests in an argon atmosphere. Although the Hg loss was significantly greater in argon than in air, the same differences among alloys were observed. Thus, from the standpoint of both vapor pressure and oxidation, the amount of Sn in the gamma 1 phase of dental amalgam has a significant and specific influence on the potential for Hg vapor emission.

Air Pollution, Indoor↗
PubMed2000

Use of an ultrahigh-speed laser scanner for constructing three-dimensional shapes of dentition and occlusion.

STATEMENT OF PROBLEM: Acquisition of the 3-dimensional shape of dental casts is useful for quantitative evaluation of the diagnosis and treatment of occlusion. PURPOSE: This study demonstrated the acquisition of data through the use of an ultrahigh-speed laser scanner and an originally developed goniometer, the use of these tools to measure the entire 3-dimensional shape of the dental cast from multiple directions, and the connection of the data measurements to reconstruct the cast's occlusion with the use of a computer. MATERIAL AND METHODS: A commercially available apparatus that emits a line laser and completes 1 scan in only 0.6 seconds was used. To compensate for the unmeasured region, the cast was measured from 4 directions on the original goniometer, and the connection of data to obtain the entire image was carried out. Further, the reconstruction of the occlusion between the upper and lower casts was attempted by transferring the upper cast data to the lower cast. RESULTS: By the data connection, the entire shape of the upper and lower casts was constructed, and the characteristic structure was reproduced. The data connections were satisfactory for the flat surfaces but less accurate for the inclined surfaces. Reconstruction of the occlusion between the upper and lower casts was accomplished. It was then possible to visualize the occlusion from arbitrary directions and sections with computer graphics. CONCLUSION: The construction of the entire 3-dimensional shape of a dental cast and the reconstruction of the occlusion were accomplished using an ultrahigh-speed measurement system and original goniometer. These results will be useful for clinical applications such as computerized diagnoses and treatment of occlusion, and for the replacement of the stone casts in the dental office by computerized data.

Calibration↗
PubMedDate not supplied

Regional odontodysplasia (Ghost teeth). A case report.

Regional odontodysplasia is a rare development anomaly affecting the teeth with an unknown etiology. This dental abnormality involves the hard tissues of the teeth that are derived from both epithelial (enamel) and mesenchymal (dentine & cementum) components of the tooth forming apparatus. Teeth in a region or quadrant of maxilla or mandible are affected to the extent that they exhibit short roots, wide open apical foramen and large pulp chamber, the thinness and poor mineralisation qualities of th enamel and dentine layers have given rise to a faint radiolucent image, hence the term "Ghost teeth". Both the permanent teeth and the deciduous teeth are affected. Females are more commonly affected than males. There is a maxillary predominance (2.5:1) with a predilection for the anterior teeth. Eruption of the affected teeth is delayed or does not occur. Because of the poor quality of the affected teeth, they cannot be rehabilitated for functional use therefore the treatment of choice is extraction with prosthetic replacement. However, necrosis and facial cellulitis appear to be a complication if these teeth are retained. A unique case of regional odontodysplasia affecting the entire right quadrant of mandible is reported here.

Female↗