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Biomedical subjects

I Gera

Publications and source records attributed to I Gera.

At least 19 recordsLinked to original sources
PubMed2000

[Effect of the quality of restorations and of dental prosthesis on the alveolar bone loss in patients with chronic destructive periodontitis].

In recent years many risk factors have been implicated in the etiology of destructive periodontitis. The quality of the previous dental works might play a decisive role in the development of periodontal attachment loss. The main objective of the present clinical study was to evaluate the aggravating role of the subgingival restorations with questionable quality and the interproximal untreated carious lesions in the progression of periodontal attachment loss in a randomly selected group of patients with destructive periodontitis. The panoramic radiographs of 170 randomly selected patients suffering with destructive periodontitis were analyzed and the quality of the approxima restorations, the presence or absence of interproximal untreated carious lesions and the interdental bone loss were recorded. The level of interproximal bone around the teeth with restorations or with approxima carious lesions were compared with the sound contralateral counterparts and with the overall average alveolar bone level. Some more than 50% of 2175 approxima restorations were faulty. 280 untreated carious lesions were present in 170 subjects. The interproximal bone loss was always greater around teeth with untreated carious lesions or with faulty restoration. The differences between the control teeth and the carious teeth were statistically significant (P < 0.01) excepting the maxillary front and mandibular premolar region. The differences between the teeth with faulty restorations and the controls were statistically significant (P < 0.01) in the mandible and in the maxillary molar region. Although there were significant differences between teeth with untreated carious lesions or with faulty restoration and the controls in many regions of the dental arch, the differences clinically were not always necessarily significant, showing only less than 0.5 mm differences in bone levels, In conclusion the faulty restorations and untreated carious lesions do not seem to be decisive aggravating risk factors leading to bone loss in patients with chronic destructive periodontitis.

Adult↗
PubMed1999

Presence of oxytalan fibers in human regenerated periodontal ligament.

The aim of the present study was to investigate whether oxytalan fibers are formed in the regenerated human periodontal ligament. 6 patients, each of them exhibiting an advanced intrabony defect, were treated with a bioresorbable membrane according to the GTR-principle. Following a healing period of 6 months, the teeth were extracted together with their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin, or with the oxone-aldehyde-fuchsin-Halmi staining method and examined in the light microscope. A regenerated periodontal ligament containing newly-formed oxytalan fibers was observed in all specimens. Many of them inserted into the newly formed cementum on the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

Absorbable Implants↗
PubMed1999

Healing of human intrabony defects following treatment with enamel matrix proteins or guided tissue regeneration.

The aim of the present study was to evaluate histologically in humans the healing of advanced intrabony defects following treatment with enamel matrix proteins (EMD) or guided tissue regeneration (GTR). Fourteen patients, each of them displaying 1 advanced intrabony defect around teeth scheduled for extraction were included in the study. The defects were treated randomly either with an enamel matrix protein derivative (Emdogain, BIORA AB, Malmö, Sweden) or with a bioabsorbable membrane (Resolut, Regenerative Material, W.L. Gore & Assoc., Flagstaff, Arizona, USA). At baseline the mean probing pocket depth (PPD) in the EMD group was 11.3 +/- 1.8 mm and the mean clinical attachment level (CAL) 12.1 +/- 2.0 mm, whereas in the GTR group the mean PPD was 11.4 +/- 2.2 mm and the mean CAL 13.3 +/- 2.3 mm. Healing was uneventful in all cases. Neither allergic reactions against EMD or the bioabsorbable membrane, nor suppuration or abscesses were observed. The clinical results revealed at 6 months in the EMD group a mean PPD of 5.6 +/- 1.3 mm and a mean CAL of 9.1 +/- 1.5 mm. In the GTR group the mean PPD was 5.6 +/- 1.3 mm and the mean CAL 10.1 +/- 1.5 mm. The histological analysis showed in the EMD group a mean 2.6 +/- 1.0 mm of new attachment (i.e. new cementum with inserting collagen fibers) and a mean 0.9 +/- 1.0 mm of new bone. In this group, the formation of new attachment was not always followed by bone regeneration. In the GTR group, the mean new attachment was 2.4 +/- 1.0 mm and the mean new bone 2.1 +/- 1.0 mm. In every case treated with GTR, the formation of new attachment was followed by a varying amount of new bone. After both types of regenerative treatment the newly formed cementum displayed a predominantly cellular character. The findings of the present study indicate that the treatment of intrabony defects with enamel matrix proteins or with bioabsorbable membranes enhances the formation of a new connective tissue attachment in humans.

Absorbable Implants↗
PubMed1999

[Laboratory and clinical investigation of multifunctional dentifrices. Clinical study of a new triclosan-containing toothpaste].

The purpose of this work was to assess the in vitro antibacterial effectiveness of three dentifrices containing antimicrobial agents and to test the in vivo anti plaque and anti gingivitis effect of a toothpaste containing triclosan (CAOLA). The in vitro tests showed a marked antibacterial effect of both triclosan and chlorhexidine containing dentifrices. The randomized clinical trial presented good evidences that the triclosan had some but statistically non significant plaque and gingivitis reduction in patients even without previous mechanical cleaning. Nevertheless the triclosan dentifrice was effective in reducing the plaque and gingivitis scores in combination with initial mechanical debridement and oral hygienic instructions.

Anti-Infective Agents, Local↗
PubMed1999

[The effect of smoking on the spread and frequency of periodontal disease].

In recent years substantial data accumulated in the literature supporting the direct detrimental effect of tobacco smoking on periodontal health. The significantly inferior periodontal condition of smokers cannot be solely attributed to poor oral hygiene, increased calculus formation and altered subgingival microflora. Smoking imposes a direct threat to the periodontal tissues. Smokers with excellent oral hygiene show significantly less periodontal bone height and attachment level than matches non-smokers. Smoking entails a 2.5 to 3.5 risk ratio for severe periodontal attachment loss. Smoking also interferes with the outcome of nonsurgical and surgical periodontal treatment and impairs periodontal regeneration. The pathomechanism of the tobacco smoking related periodontal destruction is just partly understood. Tobacco products can alter normal host responses to neutralize infections and can also stimulate pathologic mechanisms to destroy the surrounding tissues. Tobacco products can directly impair polymorphonuclear leukocyte functions. Smokers have less salivary IgA and decreased serum IgG concentration as well as depressed number of helper T lymphocytes. Consequently smoking today is considered as one of the major risk factors for destructive periodontitis. Periodontitis is also considered as a decisive risk factor for systemic diseases especially for cardiovascular disorders. A strong association has been shown between periodontal disease and coronary heart diseases, as well as between periodontal disease and cerebrovascular diseases (stroke). The subgingival microflora and the continuous latent bacteremia and endotoxemia originated from the periodontal pockets might be responsible for the damage of the vascular endothelial integrity, platelet functions and blood coagulation. Modern periodontal epidemiology rediscovered the old ide of "focal infections" and indicated that the general health has a crucial impact on the periodontal health and periodontal disease has also a major impact on the general health status of the patient.

Coronary Disease↗
PubMed1999

[Clinical experience with the treatment of gingival hyperplasia induced by calcium channel blocking agents].

The prevalence of the nifedipine-induced gingival hyperplasia is ranging from 0.5-83% in the dental literature. The pathomechanism of the nifedipine-induced gingival hyperplasia is not clearly understood. Evaluating the dental history and the course of disease of 34 patients treated and followed up at the Department of Periodontology the following answers were raised: What sort of local and systemic factors are enhancing the recurrence of the gingival overgrowth and how this can be anticipated in patients on continuous Ca channel blocking medication. Eight out of the 34 patients participating in the clinical trial did not remember the onset of their gingival overgrowth. 10 cases developed three years and three cases after less then one year of the onset of the drug administrations. 27 out of the 34 cases required gingival surgery and seven showed good clinical improvement after the hygienic phase of the comprehensive periodontal treatment. 70% of the gingival hyperplasia cases presented no clinical sign of recurrence one year after the completion of the active phase of the treatment. A positive correlation was found between the oral hygiene and the recurrence rate of gingival overgrowth. Oral hygiene seems to play a decisive role in the development of gingival enlargement. The present findings and substantial evidences from the dental literature indicate that the gingival enlargement can be successfully controlled even under the continuous nifedipine administration by meticulous professional and individual oral hygiene.

Calcium Channel Blockers↗
PubMed1999

GTR with three different types of membranes in the treatment of intrabony periodontal defects: three-year results in sixty consecutive cases.

The aim of the present study was to evaluate the clinical results at 3 years following treating intrabony periodontal defects with different nonresorbable and bioabsorbable membrane barriers. Sixty intrabony periodontal defects were treated according to the principles of guided tissue regeneration (GTR). Twenty pockets were treated with Gore Resolut, a bioabsorbable membrane; 20 were treated with Gore-Tex, a titanium-reinforced membrane; and 20 with nonresorbable Gore-Tex membrane (all manufactured by Gore Regenerative Technologies, Flagstaff, AZ). The therapeutic results were evaluated by assessing probing pocket depth (PPD), recession of the gingival margin (GR), and clinical attachment level (CAL) at baseline, at 1 and at 3 years after therapy. The postoperative phase was uneventful in all cases. At 1 year after surgery, the results showed a mean PPD reduction from 9.42 mm to 3.35 mm (p < 0.0001) with Resolut; from 10.30 mm to 4.00 with titanium-reinforced Gore-Tex (p < 0.0001); and from 8.40 mm to 3.73 mm (p < 0.0001) with Gore-Tex membranes. The mean GR increased from 1.92 mm to 3.70 mm (p < 0.001) with Resolut; from 0.47 mm to 2.85 mm (p < 0.0001) with titanium-reinforced Gore-Tex; and from 0.73 mm to 2.15 mm (p < 0.0001) with Gore-Tex membranes. The mean CAL changed from 11.35 mm to 6.92 mm (p < 0.001) with Resolut; from 10.78 mm to 6.85 mm (p < 0.0001) with titanium-reinforced Gore-Tex; and from 9.13 mm to 5.87 mm (p < 0.0001) with Gore-Tex membranes. The clinical results at 3 years were not significantly different when compared with the 1-year results (p > 0.05). No significant differences existed between the mean changes in PPD, GR, and CAL in the three different test groups. Furthermore, one tooth scheduled for extraction for periodontal and prosthodontic reasons was treated with Resolut. Histological analysis 6 months after treatment demonstrated the neoformation of a connective tissue attachment and of new alveolar bone. This additional evidence thus proved that treatment with bioabsorbable membranes according to GTR principles delivers not only clinical improvement, but also histological periodontal regeneration.

Biocompatible Materials↗
PubMed1998

[A 3-year experience with guided tissue regeneration procedures].

The Guided Tissue Regeneration (GTR) procedures are promoting a clinically and radiologically as well as histologically verifiably periodontal attachment gain. The objective of the study was to evaluate the clinical efficacy of these GTR techniques. In the past four years different barrier membranes (Gore-tex, Resolut and Guidor) were used around 318 teeth of 196 patients. 169 periodontal defects of 140 patients were followed up at least for two years. 54 patient had chronic adult type periodontitis, 67 suffered with rapidly progressing periodontitis and 15 had different severe mucogingival lesions. 111 vertical bony defects, 43 Class II-III furcation lesions and 15 mucogingival lesions were surgically corrected. The average preoperative probing depth (PD) and the clinical attachment loss (CAL) of the vertical bony defects were 5.3 +/- 1.7 mm and 6.2 +/- 1.9 mm respectively. The PD of the deepest Class III furcation lesion was 11 mm. The average gingival recession of the mucogingival lesions was 4.5 +/- 1.1 mm. The GTR technique provided the best results in the Class II-III furcation lesions, where an average 2.4 +/- 0.9 clinical attachment gain was observed one year postoperatively. The GTR techniques provided an average 1.8 +/- 1.2 mm attachment gain in the vertical bony crater cases. In both groups of cases a marked gingival recession followed the healing and the periodontal regeneration. In this way the average reduction in the probing depth exceeded the average attachment gain by more that 1.5 mm. 1 year after the operation the average radiologic bone fill was about 0.9-1.2 mm. The resorbable barrier membranes resulted in clinically significant root coverage and an average 3.5 +/- 1.7 mm gain in the width of keratinized gingiva. The success or failure of our cases were mainly determined by the patient's compliance, the level of the postoperative professional and individual oral hygiene and the number of periodontal recalls. These findings are also underlining the importance of the high standard of oral hygiene in the postoperative periodontal regeneration.

Adult↗
PubMed1997

[The role of sensitivity of oral hygiene indices in the selection of proper methodology of plaque-control clinical studies].

UNLABELLED: A double blind split-pilot study was carried out to test the potential increase in sensitivity of the Quigley and Hein (Turesky modification) plaque index using a six site recording technique against the two site technique in assessing the antiplaque effects of dentifrices. The study also evaluated the impact of asking the subjects not to brush their teeth the morning of the evaluations versus those who where hot given these instruction. The results indicated that the triclosan containing dentifrice had a significant anti-plaque effect over the placebo at 3 weeks when using both two (p = 0.003) and six (p = 0.002) sited plaque assessment methods. However the six-sited index demonstrated the greater efficacy for the active dentifrice. At six weeks no statistically significant difference between the two dentifrices was seen. The instruction of subjects not to brush before the plaque evaluation increased the mean plaque scores as well as the treatment effect at any time. IN CONCLUSION: The six-sited plaque index increased the sensitivity of the index in determining the anti-plaque efficacy of dentifrices, as well as indicating that instructing subjects not to brush preceding their plaque evaluations also increases sensitivity for determining anti-plaque efficacy of dentifrices.

Adult↗
PubMed1997

[The effect of certain stages of periodontal treatment on the regeneration of periodontal tissues].

The regenerative potential of the periodontal tissues is relatively limited. The attachment loss has long been considered as an irreversible damage of the periodontium. Most of the conventional methods of the comprehensive periodontal treatment provided no convincing evidence of true new periodontal attachment formation. Most of the surgical and nonsurgical approaches achieved either secondary gingival recession and/or long epithelial attachement. The recently introduced guided tissue regeneration techniques can make the regeneration of the fibrous periodontal attachment and convincing clinical and histological evidences of new cementum and bone formation possible, as well as the regeneration of the perpendicular Sharpey's fibers fully embedded into the matrix of the appositionally formed new cementum and bone. The theories and clinical implications of these techniques are discussed and illustrated with clinical cases.

Gingival Pocket↗
PubMed1993

[Hormonal regulation of bone metabolism].

During the past two decades our ideas about the regulation of bone formation and resorption has been expanded. At the cellular level we have learnt more about the hormonal control of the osteoblastic bone formation, the osteoclastic bone resorption and the role of the nonosseous cells in the bone metabolism. At the tissue level we have understood the coupling between osteoblastic bone formation and osteoclastic bone resorption and consequently the relation between bone turnover and skeletal growth, involution and pathologic bone changes. Though many of the findings of the recent bone researches have helped us to understand the pathogenesis of the metabolic and infectious bone diseases we do not yet have a reliable means for stimulating bone formation of structurally and functionally effective new bone in human beings. In this review we tried to summarize the research data and clinical observations showing the direct and indirect effect of calcium regulating hormones (PTH, 1,25 dihydroxyvitamin D and calcitonin) on bone metabolism.

Bone Resorption↗
PubMed1992

Effects of continuous and intermittent administration and inhibition of resorption on the anabolic response of bone to parathyroid hormone.

The role of resorption in the anabolic response of bone to parathyroid hormone (PTH) is not well understood. In contrast to the increase in bone mass induced by intermittent PTH in intact rats, continuous infusion of PTH into thyroparathyroidectomized (TPTX) rats failed to increase bone volume. The objective of this study were to determine if continuous infusions of low doses of PTH were anabolic in intact rats and if inhibition of resorption would enhance or block an anabolic action of PTH. Young male rats were treated with either continuous infusion or intermittent injections of hPTH-(1-34) for 12 days. In experiment 1, PTH, infused daily at 4 micrograms per 100 g, increased femur calcium and dry weight. Unlike infusion of 8 micrograms PTH, which did not alter bone mass, intermittent PTH at 8 micrograms was anabolic and increased bone mass by increasing trabecular thickness and number. Infusion of 16 micrograms induced hypercalcemia and death. In experiment 2, lower dose daily infusions of 0.25-4 micrograms PTH per 100 g did not increase bone mass. In experiment 3, in rats pretreated with dichloromethylene diphosphonate (Cl2MDP) to inhibit resorption and subsequently exhibiting decreased bone formation, PTH, irrespective of the method of administration, reversed the inhibitory effects of Cl2MDP on bone formation. Thus, intermittent and continuous PTH increase bone formation independently of effects on bone resorption, but only intermittent PTH increases bone mass consistently.

Animals↗
PubMed1992

[The effect of quality dentistry on the condition of the periodontium].

In the periodontal prophylaxis and therapy the most important steps are the adequate professional and individual oral hygienic interventions. Several factors are interfering with our attempts to maintain good oral hygiene either on the individual or professional basis. Among these many are artificially created during dental treatments. In the first part the clinical and experimental data on the effect of bad restorations on the health of periodontium are overviewed. The literature shows that these factors per se do no cause damage to the periodontium but the altered sub- and supragingival plaque accumulation due to these factors are responsible for the pathological conditions. The author deals with the effects of the placing and quality of crown margins, the smoothness of subgingival restorations, the shape and dimensions of interproximal areas, contact surfaces, the shape of pontics and the occlusal surface on the plaque accumulation and on the practice of professional and individual oral hygiene. The periodontal prophylactic philosophy and the standards of quality dentistry as well as the basic principle of periodontal prosthodontics are also discussed.

Dental Care↗
PubMed1991

[Possibilities of reducing the sensitivity of the neck of the tooth].

Authors overview the etiology and pathomechanism of the root hypersensitivity. The most commonly used therapeutical aids and devices are discussed. They discuss the theory of action of the drugs used for controlling root hypersensitivity. In details the dental literature of devices used on the individual bases--included different fluoride compounds, stronciumchloride, and potassium nitrate--are reviewed. In the end the authors's own clinical experience and findings with the Sensodyne toothpaste (kindly donated by the Block Drug Co.) are presented.

Dentin Sensitivity↗
PubMed1991

[Importance of periodic follow up of periodontal diseases for the maintenance of periodontal health and the longevity of dental restoration].

The major objective of the author's investigation was to determine if the progression of attachment loss, the recurrence of active phase of periodontitis and development of new carious lesions can be controlled and prevented in individuals with prior history of aggressive periodontitis provided full mouth reconstruction and maintained at a proper level of oral hygiene. The results of a group on regular periodontal recall program were compared with the five years dental and periodontal findings on a matched group of patients having not been on regular maintenance program. The well maintained group of patients' annual recall data did not vary markedly. In five years basically the same amount of attachment apparatus was maintained. The reexamination of the non recall group at the end of the fifth year shoved a total deterioration of dentition due to the progression of periodontal disease and attachment loss. Especially those of rapidly progressing periodontitis cases shoved 70 to 100% attachment loss. This comparative study attempted to outline the insufficiency of our former dental philosophy of patient management and follow up. Authors emphasize the importance of the follow up, and maintenance of a very high level.

Adult↗
PubMed1990

[The significance of the styloid process syndrome in the differential diagnosis of temporomandibular dysfunction].

Two cases are reported on, both patients came to the clinic on the suspicion of temporo mandibular joint disfunction. Their complaints was caused by overdeveloped processus styloideus. After surgical removal of the processus styloideus the complaints ceased. In cases of seemingly temporo mandibular joint disfunction not improving on conventional treatment the possibility of the processus styloideus syndroma has to be considered.

Adult↗
PubMed1988

1,25 dihydroxyvitamin D3 alone or in combination with parathyroid hormone does not increase bone mass in young rats.

Parathyroid hormone (PTH) alone is known to increase bone mass, but clinical studies of osteoporotic men suggest that when 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) is given in combination with PTH, the effect on bone growth is enhanced. To determine if 1,25(OH)2D3 alone would stimulate bone growth, young male rats were given daily subcutaneous injections of either vehicle or 2.5, 5, 10, or 20 ng 1,25(OH)2D3 per 100 g body weight for 30 days. To determine if 1,25(OH)2D3 would augment the PTH anabolic response, rats were given daily subcutaneous injections of either vehicle for 12 days; or 4 micrograms/100 g hPTH alone or in combination with 5 ng/100 g 1,25(OH)2D3; or 8 micrograms/100 g hPTH alone or in combination with 5 ng/100 g 1,25(OH)2D3. Calcium (Ca), dry weight (DW), and hydroxyproline (Hyp) of the distal femur; the rate of mineralization in the metaphysis of the proximal tibia; and serum calcium and phosphate were measured. Low normocalcemic doses of 1,25(OH)2D3 did not significantly stimulate bone growth. 1,25(OH)2D3 did not augment the PTH-stimulated anabolic effect in young male rats. Low doses (2.5 and 5 ng) of 1,25(OH)2D3 were not hypercalcemic, and there was no increase in total bone calcium or dry weight although the 5 ng dose increased trabecular bone calcium. 1,25(OH)2D3 at 10 and 20 ng increased trabecular bone DW and Hyp, but mineralization was impaired and rats were hypercalcemic. 1,25(OH)2D3 in combination with PTH did not augment the PTH stimulation of bone growth as trabecular and cortical bone Ca, DW, and HYP were not increased in rats given both hPTH and 1,25(OH)2D3 compared with values for rats treated with hPTH alone.

Animals↗