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Biomedical subjects

S Nyman

Publications and source records attributed to S Nyman.

At least 91 records · Page 5Linked to original sources
PubMed1985

Healing following reimplantation of teeth subjected to root planing and citric acid treatment.

The aim of the present study was to examine the effect of citric acid treatment on periodontal healing around teeth which were extracted, root planed and then reimplanted. Maxillary incisors and mandibular incisors, premolars and molars of 5 monkeys were used. The teeth were divided into 3 experimental groups. In 1 group, the teeth were extracted and immediately reimplanted into their own sockets. In a 2nd group, the teeth were extracted, root planed to a level corresponding to 50-75% of the root length and then reimplanted. In the 3rd group, periodontal breakdown extending to 50-75% of the root length was first induced by placing orthodontic elastic ligatures around the teeth. They were then extracted and root planed and transplanted into the sockets of the contralateral, periodontally healthy teeth which had just been extracted. Half the number of the teeth of groups 2 and 3 were treated with citric acid before reimplantation or transplantation. The animals were sacrificed after 6 months of healing. The jaws were removed and histological specimens prepared for microscopic examination. With the exception of a limited coronal regrowth of new cementum in the apical part of the planed portion of a few roots, connective tissue attachment failed to reform on most root surfaces deprived of their periodontal ligament tissue. Healing was most frequently characterized by root resorption and ankylosis. These were the most predominant features of healing both on root surfaces which had been deprived of the ligament tissue by mechanical means or during a course of experimentally-induced periodontal disease, and occurred in citric acid as well as non-citric acid treated roots. The findings imply that the result of healing following tooth reimplantation or transplantation is determined by the type of cells that repopulate the wound area adjacent to the denuded root surface.

Animals↗
PubMed1985

Epidemic ascariasis--evidence of transmission by imported vegetables.

This paper describes a local Ascaris lumbricoides epidemic with special reference to the factors giving rise to its breaking out. Ten of the 12 patients were children, and six patients were definitely diagnosed for Ascaris lumbricoides worms in their faeces in addition to worm eggs. The epidemic was probably due to imported vegetables and took place in the early winter 1982 and 1983.

Adult↗
PubMed1984

New attachment formation as the result of controlled tissue regeneration.

The present study was designed to examine whether new attachment forms on root surfaces previously exposed to plaque by preventing the oral epithelium and the gingival connective tissue from participating in the process of healing following treatment. 4 roots in each of 3 monkeys were used as test units while the roots of contralateral teeth served as controls. A surgical procedure was first used to expose the coronal half of the buccal root surfaces. Plaque was allowed to accumulate on the exposed surfaces for a period of 6 months. Subsequently, soft tissue flaps were raised and the root surfaces were carefully scaled and planed. The crowns of the test and control teeth were resected and the mucosal flaps were repositioned and sutured in such a way that the roots were properly covered. Immediately prior to suturing, membranes (Millipore filter or Gore-tex membrane) were placed over the denuded root surfaces of the test teeth in order to prevent granulation tissue from the soft tissue flaps from reaching the roots during healing. The monkeys were sacrificed 3 months later. The jaws were removed and histological sections of test and control roots including their periodontal tissues were produced. New cementum with inserting collagen fibers was observed on the previously exposed surfaces of both test and control roots. However, the test surfaces exhibited considerably more new attachment than the control surfaces, indicating that the placement of the membrane favoured repopulation of the wound area adjacent to the roots by cells originating from the periodontal ligament.

Alveolar Process↗
PubMed1984

Long-term maintenance of patients treated for advanced periodontal disease.

The aim of the present investigation was to evaluate the periodontal conditions of a group of patients who, following active treatment of extremely advanced periodontal disease, had been maintained for 14 years in a well-supervised maintenance care program. The present sample included 61 subjects out of an initial group of 75 individuals who in 1969 were referred to and treated by the authors. Following an initial examination, the patients were given detailed instructions in proper plaque control measures and were subjected to scaling and root planning and surgical elimination of pathologically deepened pockets. After the termination of the active treatment phase, the patients were placed in a maintenance care program including recall appointments every 3-6 months. At the initial examination, immediately after the completion of the active treatment phase and then once a year, all patients were examined regarding oral hygiene, gingival conditions, probing depths and clinical attachment levels. In addition, the interproximal alveolar bone height was determined from full mouth radiographs obtained before active treatment, at the completion of active therapy and 1, 3, 5, 8, 10, 12 and 14 years after treatment. The results from the repeated examinations demonstrated that treatment of advanced forms of periodontal disease resulted in clinically healthy periodontal conditions and that this state of "periodontal health" could be maintained in most patients and sites over a period of 14 years. It was also demonstrated that the treatment and maintenance programs described were equally effective in young and older patients. The individual mean values describing probing depths, attachment levels, and bone heights did not vary significantly over the 14 years of observation. A more detailed analysis of the data revealed, however, that a small number of sites in a few patients lost a substantial amount of attachment. This attachment loss occurred at different time intervals during the course of the maintenance period. Thus, 43 surfaces in 15 different patients were exposed to recurrent periodontal disease of a significant magnitude. This recurrent inflammatory periodontal disease caused the loss of 16 teeth in 7 different patients during the maintenance period. The data reported question the validity of using individual mean values to describe alterations of the periodontal conditions during maintenance following active periodontal therapy.

Adult↗
PubMed1984

Connective tissue reattachment as related to presence or absence of alveolar bone.

The present study was designed to examine if alveolar bone, located adjacent to a root surface deprived of its periodontal ligament and cementum layer, can stimulate the reformation of a connective tissue attachment. The maxillary and mandibular incisors in 3 monkeys were extracted. Immediately after tooth extraction, the buccal root surfaces of the incisors from the left side of the jaws were planed by means of curettes to a level corresponding to half the root length. All teeth were then reimplanted into their original sockets. However, before tooth reimplantation, the buccal alveolar bone plate was removed in 2 of the monkeys to a level corresponding to half the depth of the sockets. The animals were sacrificed 6 months after the reimplantation procedure. The jaws were removed and histological sections of the experimental teeth and adjacent periodontal tissues were produced. The sections were analyzed in the microscope and subjected to histometric measurements. The results demonstrated that, irrespective of the presence or absence of alveolar bone, a fibrous reattachment failed to form on that part of the reimplanted teeth which had been deprived of their periodontal ligament. This indicates that alveolar bone located adjacent to a root surface may have limited influence on the biological conditions which determine whether periodontal healing results in connective tissue reattachment or new attachment.

Alveolar Process↗
PubMed1984

Potentials for root resorption during periodontal wound healing.

The present study was undertaken to examine whether (1) the process of resorption, which invariably affects periodontitis involved reimplanted roots facing bone or gingival connective tissue during healing, is a transient phenomenon and, (2) root resorption can be prevented by permitting downgrowth of epithelium along the root surface. A total of 24 teeth in 2 monkeys (Macaca cynomolgus) was subjected to experimental periodontal tissue breakdown by the placement of elastic ligatures around the teeth. The ligatures were left in situ until about 50% of the supporting tissues had been lost. Following removal of the ligatures, the teeth were extracted and the denuded portions of the roots were scaled and planed. The crowns of the teeth were resected and the root canals filled with guttapercha. The roots were subsequently implanted into sockets prepared in the jaw bone in such a way that each root was embedded in bone except for a portion which was in contact with gingival connective tissue. 1 month prior to sacrifice of the animals, the cut surface of the coronal part of the roots was exposed by removal of the covering soft tissue. The epithelium was thereby allowed to migrate into the wound. Implantation of the roots was scheduled to provide healing periods of 1, 2, 3, 4, 8, 12, 16, 20 and 24 weeks before exposure of the roots. The histologic examination of the implant specimens disclosed that replacement resorption was a progressive process which eventually resulted in the elimination of the transplanted roots. It was possible to prevent root resorption in this model by permitting apical downgrowth of epithelium along the root surface during the initial phase of healing. The results are discussed in relation to procedures used in periodontal therapy.

Animals↗
PubMed1984

Long-term effect of surgical/non-surgical treatment of periodontal disease.

The present investigation describes the effect of periodontal therapy in a group of patients who, following active treatment, were monitored over a 5-year period. One aim of the study was to analyze the rôle played by the patients' self-performed plaque control in preventing recurrent periodontitis. In addition, probing depth and attachment level alterations were studied separately for sites with initial probing depths of greater than or equal to 4 mm which were treated initially by either surgical or non-surgical procedures. Following active treatment (surgical/non-surgical), the patients were maintained on a plaque control regimen for 6 months, which included professional tooth cleaning once every 2 weeks. During the subsequent 18 months, the interval between the recall appointments was extended to 12 weeks and included prophylaxis as well as oral hygiene instruction. Following the 24-month examination, the interval between the recall appointments was further extended, now to 4-6 months. In addition, the maintenance program was restricted to oral hygiene instruction and professional, supragingival tooth cleaning, but further subgingival instrumentation was avoided. Clinical examinations including assessments of the oral hygiene, the gingival conditions, the probing depths and the attachment levels were performed at Baseline and after 24 and 60 months after completion of active therapy. Assessments of plaque and gingivitis were repeated annually. The results of the examinations showed that the patients' standard of self-maintained oral hygiene had a decisive influence on the long-term effect of treatment. Patients who during the 5 years of monitoring consistently had a high frequency of plaque-free tooth surfaces showed little evidence of recurrent periodontal disease, while patients who had a low frequency of plaque-free tooth surfaces had a high frequency of sites showing additional loss of attachment. The present findings demonstrated that sites with an initial pocket depth exceeding 3 mm responded equally well to non-surgical and surgical treatments. This statement is based on probing depth and attachment level data from sites which were free of plaque at the 6-, 12-, 24-, 36-, 48-, and 60-month reexaminations. It is suggested that the critical determinant in periodontal therapy is not the technique (surgical or non-surgical) that is used for the elimination of the subgingival infection, but the quality of the debridement of the root surface.

Adult↗
PubMed1984

Endodontic complications following periodontal and prosthetic treatment of patients with advanced periodontal disease.

A retrospective analysis was carried out to determine the frequency and onset of endodontic complications occurring in 52 patients treated for advanced periodontal disease. Comparisons were made between teeth which, following periodontal treatment, were used as abutments in fixed prosthetic reconstructions and nonabutment teeth. The study included 672 teeth with initially vital pulps (255 abutment teeth and 417 nonabutment teeth). The observation period varied from 4 to 13 years with a mean of 8.7 years. Pulpal necrosis including periapical lesions developed with a significantly higher frequency in abutment teeth than in nonabutment teeth (15% vs. 3%). The majority of these lesions did not appear until several years following the completion of active treatment. Conceivable reasons for the development of pulpal necrosis in teeth subjected to combined periodontal and prosthetic treatment are discussed.

Adult↗
PubMed1984

Periodontal response after tooth movement into intrabony defects.

The present study was undertaken since conflicting evidence exists regarding the effect of such tooth movement on levels of connective tissue attachment. Localized intrabony pockets were produced around isolated incisors in four rhesus monkeys. The root surfaces were planned to the level of the bone at the base of the angular bony defects. An oral hygiene regime was begun and continued for the remainder of the study. The experimental teeth were moved orthodontically into, and through, the original area of the intrabony defect. Two months after cessation of active tooth movement, block specimens were removed for histologic analysis. Control specimens comprised those teeth with induced periodontal defects, but without tooth movement. In specimens not subjected to tooth movement, angular bony defects were present and epithelium lined the root surface to the apical extent of instrumentation. The alveolar bone adjacent to the orthodontically moved teeth no longer had angular defect morphology. On the pressure side, epithelium lined the root surface, was interposed between root surface and bone and terminated at the apical limit of root instrumentation. On the tension side, the crest of the bone was located apical to the level of root planing, and epithelium lined the instrumented portion of the root surface. It was concluded that orthodontic tooth movement into intrabony periodontal defects was without effect upon the levels of connective tissue attachment.

Alveolar Process↗
PubMed1984

On functional strain in fixed mandibular reconstructions. II. An in vivo study.

Six linear strain gauges and one rosette strain gauge were used on one partially dentate subject to study various types of functional deformation in a six-unit conventionally designed fixed mandibular bridge and a five-unit cantilever fixed mandibular bridge. The results of this study show that the clinical straining pattern was complex and different from those recorded in laboratory model studies of the same case. It was therefore concluded that functional deformations of fixed dental appliances can be studied accurately only in clinical experiments. Fundamentally different straining patterns were observed between the conventionally designed bridge and the cantilever one. The clinical significance of these results are discussed in relation to prosthetic treatment with various types of fixed-bridge constructions.

Bite Force↗
PubMed1984

The Swedish dental health programme for adults.

The Swedish dental health programme for adults provides guidelines for the prevention of caries and periodontal disease. Swedish dentists are recommended to follow the principles of the programme, which was issued by the Swedish National Board of Health and Welfare. The article describes the background, the preparation and the content of the programme.

Adult↗
PubMed1983

Regulation of development of leucine uptake activity by glutamine in the scutellum of germinating barley grain.

Scutella from ungerminated grains of barley (Hordeum vulgare L. cv Pirkka) take up leucine at a slow rate, which increases rapidly during germination. When endosperms were removed from the grains after imbibition for 4 hours or after germination for 12 or 72 hours, the increase in the rate of leucine uptake was greatly accelerated during subsequent incubation of the embryos or scutella. These increases were rapidly inhibited by cordycepin and cycloheximide, suggesting that protein synthesis, probably synthesis of the carrier protein, was required for the development of the uptake activity.In separated embryos or scutella, the increases in the leucine uptake activity were inhibited by glutamine. The inhibitions caused by glutamine and cycloheximide were not additive, suggesting that glutamine did not interfere with the function of the carrier but repressed its synthesis. Glutamine did not inhibit the simultaneous increase in peptide uptake; in this respect, its effect was specific for leucine uptake, which appears to be due to a general amino acid uptake system.Some other protein amino acids also inhibited the increase in leucine uptake without inhibiting the increase in peptide uptake. However, these effects were smaller than that of glutamine.These results suggest that the transfer of leucine (and other amino acids) from the endosperm to the seedling in a germinating barley grain is regulated at the uptake step by repression of the synthesis of the amino acid carrier protein by glutamine and-possibly to a lesser extent-by some other amino acids taken up from the endosperm.

Journal Article↗