Responses of calcitonin gene-related peptide-immunopositive nerve fibres in the periodontal ligament of rat molars to experimental tooth movement.

Nerve fibres showing CGRP-immunoreactivity were exclusively distributed around blood vessels in the periodontal ligament of normal teeth. The CGRP-positive nerves as well as the vessels were more dense during tooth movement and reached a maximum density and intensity of immunoreaction after 3 days. After that, the immunoreactive nerves gradually disappeared, and returned to the control level by the 7th day. Some of the CGRP-nerves were adjacent to bone resorptive lacunae at 3 days when active remodelling of alveolar bone was taking place. These findings suggest that the distribution of CGRP-positive nerves is dynamically changed around the blood vessels in the periodontal ligament during tooth movement, and that CGRP might affect the regulation of blood flow in the ligament. CGRP is possibly involved in the tissue remodelling, directly or indirectly, in addition to its function as a neurotransmitter.     

The development of air medical services in Czechoslovakia

The Czechoslovakian system of centralized dispatch of all emergency medical services prevents competition between ground ambulances and air medical services. Although this program is less than two years old, remarkable progress has pushed Czechoslovakia to the forefront of modern-day air medical transport. However, the future of Czechoslovakian air medical transport will require the acquisition of better-performing EMS helicopters and accessibility to medical equipment using Western technology. As with all current United States helicopter EMS systems, Czechoslovakia will face many of the financial considerations required in funding this extensive and elaborate project.     

Mucormycosis of the mandible

A case of mucormycosis of the mandible and adjacent soft tissue is presented. The rampant osteomyelitis that developed over a two-month period shows the necessity of early medical and surgical intervention. The management of these patients includes aggressive medical management of underlying problems, high-dose amphotericin B administration, and early surgical debridement of all involved tissues.     

Adequacy and effectiveness of a public dental care program for old-age pensioners

The purpose of the present work was to assess the adequacy and effectiveness of a public dental program for old-age pensioners. The dental care program offered free consultation and treatment at reduced prices to all pensioners (3072) in a municipality near Oslo in 1979. To study treatment need and access to dental care, a random sample of 430 pensioners was drawn from the total population of old-age pensioners; 371 persons were clinically examined. Of the 3072 old-age pensioners 23.7% responded positively and indicated that they were interested in the program, whereas 19.8% accepted, and 14.6% had the treatment carried out. The program adequacy was low and became lower when more restricted criteria for access to dental services were used. The program effectiveness was 18% or 16%, depending on which criteria were used for access. Acceptance of the program was highest among people who were aware of it, had natural teeth, had a dental problem, did not have their own dentist, had limited education, or were among the young pensioners.     

Artificial periodontal defects around incisor teeth of beagle dogs

The aim of the present experiment was to investigate if it is possible to create deep periodontal defects around incisor teeth of beagle dogs with the use of orthodontic elastic bands, to investigate if this method is reproducible and predictable, and to evaluate if such defects possess the histopathological characteristics of naturally occurring periodontitis. In eight beagle dogs the dentogingival fibres around four upper incisors, ³I₃ and ²I₂, were cut to the level of the alveolar bone. Orthodontic elastic bands were placed in these deepened sulci and removed after 8 weeks. Clinical data (probing depth and gingival recession) were recorded at the start of the experiment, immediately following removal of the elastic bands, and 2, 6, 14, and 30 weeks thereafter. The dogs were sacrificed on different dates so that is was possible to analyse defects histometrically 3, 7, 15, or 31 weeks after elastic removal. Contralateral defects one week after elastic band removal served as controls. Micrographic color slides of the histological sections were analysed using a Ferranti-Cetec digitizer. Immediately after elastic band removal mean values for probing depth and gingival recession were approximately 5.5 mm and 2.0 mm, respectively. Histometrical assessments revealed a loss of attachment of approximately 3.0 mm. The differences in probing depths between Contralateral defects in the same dog were small indicating rather high reproducibility of the method. Because of wide variations in probing depth and histometrical dimensions between dogs, it was concluded that the present method is not fully predictable. Upon elastic removal values for probing depth decreased with approximately 1.5 mm, the result being a moderately deep defect of around 4 mm. Histometrically there was no evidence that the apical positioning of the junctional epithelium was reversible after elastic removal. However, alveolar bone repair could be demonstrated in the 7, 15, and 31 weeks specimens. It was concluded that because of this bone repair, the present defects do not possess all histopathological characteristics of naturally occurring periodontitis.     

Evaluation of the clinical behavior of resin modified glass ionomer cement on primary molars: a comparative one-year study

AIM: The objectives of the present study were to evaluate and compare the clinical behavior of resin modified glass ionomer cement (RMGIC) on primary molars with conventional and modified cavity preparations. METHODS AND MATERIALS: Forty-two children, 5-9 years of age, having bilateral initial occlusal caries on the mandibular primary second molars were selected for the study. A split mouth design was employed where conventional Class I cavities with a 90 degrees cavosurface angle were prepared randomly on primary second molars on one side and modified cavities with a 1 mm straight bevel along the cavosurface margin on the contra-lateral side. These cavities were restored with RMGIC. The restorations were evaluated during subsequent visits, for a period of one year. RESULTS: At the end of one year, 90% of the restorations survived in the conventional cavity group whereas 100% of the restorations survived in the modified cavity group. CONCLUSION: Incorporation of a bevel in Class I cavities increases the survival rate of RMGIC restorations. There was no significant difference in the clinical behavior between the two groups. However, beveling does contribute to long term clinical success of these restorations. CLINICAL SIGNIFICANCE: Incorporation of a straight bevel in conventional cavities will improve the retention of RMGIC by increasing the bonding area and enhancing the desired properties of the material.     

Soft tissue response to mandibular advancement using 3D CBCT scanning

This prospective longitudinal study assessed the 3D soft tissue changes following mandibular advancement surgery. Cranial base registration was performed for superimposition of virtual models built from cone beam computed tomography (CBCT) volumes. Displacements at the soft and hard tissue chin (n = 20), lower incisors and lower lip (n = 21) were computed for presurgery to splint removal (4-6-week surgical outcome), presurgery to 1 year postsurgery (1-year surgical outcome), and splint removal to 1 year postsurgery (postsurgical adaptation). Qualitative evaluations of color maps illustrated the surgical changes and postsurgical adaptations, but only the lower lip showed statistically significant postsurgical adaptations. Soft and hard tissue chin changes were significantly correlated for each of the intervals evaluated: presurgery to splint removal (r = 0.92), presurgery to 1 year postsurgery (r = 0.86), and splint removal to 1 year postsurgery (r = 0.77). A statistically significant correlation between lower incisor and lower lip was found only between presurgery and 1 year postsurgery (r = 0.55). At 1 year after surgery, 31% of the lower lip changes were explained by changes in the lower incisor position while 73% of the soft tissue chin changes were explained by the hard chin. This study suggests that 3D soft tissue response to mandibular advancement surgery is markedly variable.     

Histologic evaluation of the buccal and lingual bone plates in anterior dog teeth: possible influence on implant dentistry

Background: Recent studies in animals have shown pronounced resorption of buccal bone plate after immediate implantation. The sectioning of experimental material for histologic evaluation of the bone plates could provide valuable information about the possible effect of bone exposure in periodontal and implant surgeries. Methods: Twenty‐four incisors were collected from dogs. After decalcification, the blocks were immersed in paraffin and bucco‐lingual histologic sections were examined under light microscope. Some sections were reserved for immunohistochemical analysis. Results: The bone density, the width of the bone plates, and the percentage of vessels presented in the periodontal ligament and periosteum were analyzed in the buccal and lingual bone plates, which were divided corono‐apically into thirds. The buccal bone plates showed statistically higher bone density compared to the lingual bone plates in the coronal thirds. The width of both bone plates increased from the coronal to the apical third, but all the buccal thirds were significantly thinner compared to the lingual thirds. No statistically significant differences were found between the bone plates for the percentage of area occupied by the blood vessels in the periodontal ligament or periosteum. Conclusion: It is reasonable to conclude that the higher bone density, represented by the lower number of marrow spaces, in association with the thinner aspect of the buccal bone plates made them more fragile to absorb compared to the lingual bone plates, especially during mucoperiosteal procedures.