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[Dissertations 25 years after date 4. Periodontal surgery an important component of periodontal treatment].

The aim of periodontal treatment is to make and keep the periodontal tissues healthy. A proper diagnosis including the assessment of the different risk factors is essential before successful treatment can be carried out. Oral hygiene instruction together with supra- and subgingival cleaning is a basic part of the treatment. Antibiotic treatment and smoking cessation programs also contribute to a good clinical result. Until the seventies, when almost nothing was known about riskfactors and antibiotic therapy, no study was performed to assess the long-term effect of periodontal surgery being part of the treatment. Therefore a study was performed to assess clinically, radiographically and histologically the effect of periodontal surgery and oral hygiene on artificial periodontal defects. The results were reported in the thesis 'Surgery and oral hygiene on artificial periodontal defects in beagle dogs'. This study established that periodontal surgery can contribute to a healthy periodontium. A good oral hygiene is a prerequisite. These results have been confirmed by a long-term study in private practice. Pocketdepths of 5 mm and more after initial treatment is a good criterion in the decision making for periodontal surgery.

Anti-Bacterial Agents↗

Antigens of Actinobacillus actinomycetemcomitans identified by immunoblotting with sera from patients with localized human juvenile periodontitis and generalized severe periodontitis.

Sonicated whole cell extracts and outer membrane proteins from this bacterium were analysed using sera from 31 young patients with localized juvenile periodontitis, 55 young adults with generalized severe periodontitis and from 31 healthy control subjects. The sonicate contained 13 major bands (14-78 kDa); a greater proportion of sera from patients with generalized periodontitis reacted with 40 and 70 kDa antigens when compared with sera from localized juvenile periodontitis and controls. In contrast, a lower proportion of sera from localized juvenile periodontitis reacted with the 29 kDa antigen when compared with severe periodontitis and controls. The outer membrane proteins contained four main antigens of 19, 24, 35 and 67 kDa, which reacted with sera from all three groups. Although, so far, the findings do not allow discrimination between the two diseases, antibody responses to the 29, 40 and 70 kDa antigens of A. actinomycetemcomitans may help in the assessment of severity of the disease in patients with periodontitis.

Actinobacillus↗

Longitudinal periodontal tissue alterations during supportive therapy. Findings from subjects with normal and high susceptibility to periodontal disease.

AIM: The aim of the study was to evaluate disease progression during supportive periodontal therapy in (i) a group of 225 subjects with "normal" (NG) and (ii) a group with high susceptibility (HSG; n= 109) to periodontal disease (based on their baseline disease status). MATERIAL AND METHODS: The following variables were recorded at the baseline examination (1 year after they received non-surgical periodontal therapy) and at the re-examination after 12 years of maintenance: number of teeth, plaque, probing pocket depth, probing attachment level, bone level in full mouth radiographs. All assessments were performed in a standardized manner and by well-trained and calibrated examiners. Supportive periodontal therapy was delivered 3-4 x per year and included repeated oral hygiene instruction and debridement. In addition, sites that bled on probing and had a PPD value of > or = 5 mm received subgingival instrumentation. RESULTS: A comparison between the findings at baseline and after 12 years revealed that in the NG, most subjects maintained their periodontal condition unchanged during the maintenance period; only a few subjects experienced tooth loss and the figures describing the mean amount of bone and attachment loss were small (0.5 mm and 0.3 mm respectively). The HSG patients experienced some tooth loss and also lost significant amounts of bone and attachment during the 12 years of SPT. Thus, in this group of subjects, the mean overall PAL loss amounted to 0.8 mm, i.e., 0.06 mm/tooth surface/year. In the NG, the overall attachment loss was significantly smaller: 0.5 mm, i.e. 0.04 mm/tooth surface/year. CONCLUSION: In subjects with a high susceptibility for periodontal disease who had been treated for this condition by non-surgical means, an SPT program including regularly repeated oral hygiene instruction and subgingival debridement, made it possible to maintain bone and attachment levels at a reasonably stable level over a 12-year period. A similar SPT provided to a group of subjects with normal susceptibility to periodontal disease, on the other hand, prevented almost entirely major tooth, bone and attachment loss.

Adult↗

Human periodontal ligament cell sheets can regenerate periodontal ligament tissue in an athymic rat model.

Conventional periodontal regeneration methods remain insufficient to attain complete and reliable clinical regeneration of periodontal tissues. We have developed a new method of cell transplantation using cell sheet engineering and have applied it to this problem. The purpose of this study was to investigate the characteristics of human periodontal ligament (HPDL) cell sheets retrieved from culture on unique temperature-responsive culture dishes, and to examine whether these cell sheets can regenerate periodontal tissues. The HPDL cell sheets were examined histologically and biochemically, and also were transplanted into a mesial dehiscence model in athymic rats. HPDL cells were harvested from culture dishes as a contiguous cell sheet with abundant extracellular matrix and retained intact integrins that are susceptible to trypsin-EDTA treatment. In the animal study, periodontal ligament-like tissues that include an acellular cementum-like layer and fibrils anchoring into this layer were identified in all the athymic rats transplanted with HPDL cell sheets. This fibril anchoring highly resembles native periodontal ligament fibers; such regeneration was not observed in nontransplanted controls. These results suggest that this technique, based on the concept of cell sheet engineering, can be useful for periodontal tissue regeneration.

Acrylic Resins↗

The relationship between periodontal conditions and perceptions of periodontal health among Pakistani immigrants in Norway.

The purpose of the present study was to assess the periodontal status of Pakistani immigrants in Norway, a Third World population in an industrialized country. The findings were related to treatment needs, socio-demographic variables and cultural beliefs about periodontal health. The mean number of remaining teeth ranged from 27.7 in the 20-24-year-old age group to 25.1 in the group of 35-year-olds and older. Very few of the study population had no plaque or no subgingival calculus. Only 7.5% of the participants exhibited no bleeding at any index teeth. Age and residence in Pakistan were the strongest predictors of subgingival calculus and pocket depth. Those from the rural areas of Pakistan had deeper pockets than those from the cities. The data showed a population with high prevalences of teeth with plaque, subgingival calculus and frequent gingival bleeding, but few sites with deep pockets. A periodontal treatment need index would indicate a substantial amount of treatment time. The present study suggests that also the perceived periodontal conditions, should be taken into account when periodontal services and health education strategies are planned. The concept of periodontal illness is introduced, defined as a person's perceptions and interpretations of periodontal symptoms.

Adult↗

Salivary IgG, a parameter of periodontal disease activity? High responders to Actinobacillus actinomycetemcomitans Y4 in juvenile and adult periodontitis.

The concentration of salivary IgG and IgA and the levels of salivary IgG and IgA antibodies to Actinobacillus actinomycetemcomitans Y4 were measured by ELISA in 205 persons including patients with juvenile and adult periodontitis as well as healthy subjects. Compared to the concentration observed in subjects with a healthy periodontium, a significantly increased concentration of salivary IgG was found in 34% of the patients with moderate adult periodontitis and in 57% of the patients with severe adult periodontitis. The level of salivary IgA was less influenced by the periodontal condition. The level of salivary IgG antibody to A. actinomycetemcomitans was significantly elevated in 55% of the patients with untreated juvenile periodontitis and in 28% of the patients treated for JP. 28% of the patients with adult periodontitis had a significantly elevated level of IgG antibody to A. actinomycetemcomitans Y4. Significantly elevated levels of IgA antibody to this bacteria was found less frequently, 27% in untreated JP, 20% in treated JP and 17% in adult periodontitis.

Actinobacillus↗

Crevicular interleukin-1 beta in moderate and severe periodontitis patients and the effect of phase I periodontal treatment.

Interleukin-1 beta (IL-1 beta), a potent stimulator of bone resorption, has been implicated in the pathogenesis of periodontal destruction. However, the relationship between cytokines and periodontal disease has not been studied sufficiently to allow definitive conclusions. The aims of this study are to investigate crevicular IL-1 beta and the clinical status of patients with periodontitis and the effect of phase I periodontal therapy on levels of IL-1 beta. For this study, 130 gingival crevicular fluid (GCF) samples were harvested from non-inflamed (15) and diseased sites (115) in 11 patients with periodontitis. The gingival index (GI) and probing depth (PD) of each site was recorded initially and one month after treatment. The amount of IL-1 beta in the GCF was measured by enzyme-linked immunosorbent assay (ELISA) using an antibody specific for this cytokine. Before treatment, IL-1 beta was found in 12 of 15 non-inflamed gingival crevices and in 112 of 115 diseased pockets. The amount of IL-1 beta varied from 4.03 to 511.12 pg/site. The average amount of IL-1 beta from diseased sites was 3-fold greater than that from non-inflamed sites. Both total amount of IL-1 beta and the GCF volume, but not IL-1 beta concentration, were found to be correlated, positively, with GI score and PD. After therapy, 63 sites from 7 patients were re-examined, and the amount of IL-1 beta in 49 of 63 sites was found to have declined. These data suggest that the amount of crevicular IL-1 beta is closely associated with periodontal status. This relationship may be valuable in monitoring periodontal disease activity.

Adult↗

Assessment of periodontal knowledge and periodontal status of an adult population in Jordan.

The aim of this study was to assess periodontal knowledge and periodontal status in 20-60-year-old adult population in northern Jordan. A convenient sample consisting of 722 adults was included in this study. A questionnaire incorporating items related to socio-demographic and periodontal knowledge questions was completed before clinical examination, using the Community Periodontal Index of Treatment Needs (CPITN). The results showed that the proportions of subjects who reported bleeding gums, gums' irritation, rough tooth surface and gum disease decreased steadily with age, there is an evident linear trend with high statistical significant difference among various age groups (P < 0.001). Furthermore, the proportions of subjects who answered correctly the periodontal knowledge questions related to plaque definition and its role in disease aetiology and prevention, decreased with age, with a high significant difference for all knowledge questions (P < 0.001). The prevalence of subjects with healthy periodontium (score 0) decreased with age, being 41.1% among 20-29-year-old group and 11.1% in 50-60-year-old group. Similar trend was seen for bleeding on probing (score 1) whilst calculus deposit (score 2) was the major problem in all age groups over 29 years. The prevalence of periodontal pockets was relatively low, with a range of 4.5-18.6% for shallow pockets (score 3) and 2.9-11.1% for deep pockets in younger and older age groups, respectively. Younger age group had more healthy sextants than older age groups. In addition, sextants with bleeding on probing were highest in 20-29-year-old age group (1.8) compared with that in 50-60-year-old age group (0.60) whilst those with calculus deposits varied slightly among different age groups (1.50-1.65). Sextants affected by shallow or deep pockets increased steadily with age. Such a finding was also noted in excluded sextants, with an increase from 0.15 at 20-29 year-old group to 0.94 at the age of 50-60 years. It is concluded that health knowledge and status related to periodontal disease is still poor in northern Jordan. Therefore, dental health education provision is necessary to improve oral health knowledge and conditions among population in general and among older population in particular.

Adult↗

Periodontal microflora of HIV infected patients with periodontitis.

The aim of this study was to determine the microbial profile of periodontal lesions in HIV seropositive patients and to compare it with rapidly progressing periodontal lesions in systemically healthy patients. The subgingival microflora of 20 CDC II, 20 CDC III, 20 CDC IV/V and 20 systemically healthy patients with rapidly progressing periodontitis was examined. Four sites with greatest probing depth in each patient were selected for microbiological sampling. The samples were cultured aerobically and anaerobically for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. The microflora of periodontitis lesions within the three stages of the HIV infection was similar to that of progressing periodontitis in systemically healthy adults including Campylobacter rectus, Capnocytophaga spp., Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Selenomonas spp. and Peptostreptococcus micros. However, HIV seropositive periodontitis lesions harboured a range of exogenous pathogens rarely associated with common types of periodontitis including Staphylococcus aureus, Enterobacter cloaca, Pseudomonas aeruginosa, Candida albicans, Enterococcus faecalis, Enterococcus avium, Clostridium difficile, Aspergillus fumigatus, Klebsiella pneumoniae and Mycoplasma incognitum. The lack of immune effector and regulatory cells in HIV infected patients could in fact explain the increase of some opportunistic pathogens and the characteristic and rapidly progressing nature of the periodontal disease in these patients.

Journal Article↗

Microbiological findings of infected root canals and adjacent periodontal pockets in teeth with advanced periodontitis.

The purpose of the present study was to examine the flora from the root canals and periodontal pockets of teeth with advanced periodontal disease in order to compare the predominant cultivable microflora from the canals with those found in the adjacent periodontal pockets. Three samples were collected from each of sixteen patients, one from the root canal and two from the adjacent periodontal pocket in two different sites. Criteria for inclusion in the survey were pocket depth of greater than or equal to 7 mm, intact clinical crowns, and lack of periapical lesions. The study has demonstrated that the microorganisms present in the root canals of caries-free teeth with advanced periodontitis generally resembled those found in the adjacent periodontal pockets. The similarity in the recovery of organisms in the current study suggests that the pocket could be the source of the root canal infections. Further investigation is needed to clarify whether such factors as duration of periodontitis and age of the patient play a role in pulpal pathosis and whether the presence of specific bacterial species is also a factor in the etiology and pathogenesis of pulp disease.

Bacteria↗

Gender differences in HLA phenotype frequencies found in German patients with generalized aggressive periodontitis and chronic periodontitis.

HLA antigens have been considered as risk factors for periodontitis. Differences in prevalence and in the extent of attachment loss between males and females have suggested that gender-dependent HLA deviations could play a role in individual predisposition to periodontitis. The aim of the present study was therefore to investigate the incidence of gender-dependent HLA associations in 50 patients with generalized aggressive periodontitis (AP) and 102 patients with chronic periodontitis (CP) in comparison to 102 probands without any attachment loss caused by periodontitis. HLA typing was carried out using a microlymphocytotoxic test and a polymerase chain reaction with sequence-specific primers (PCR-SSP). Female AP patients showed an increase in the frequency of HLA-A*68/69 and a decrease in the frequency of DRBblank* (non-DRB3/4/5*) and DQB1*05-positive probands. Only in female CP patients was HLA-DQB1*0303 absent, whereas HLA-DQB1*06 homozygosity increased significantly. With regard to the (AP + CP) periodontitis group as a whole, the increased frequency of HLA-DQB1*06 homozygosity in females was similar to the findings obtained in the AP group. Evidently, gender is a confounding variable, which should be considered in further studies of HLA and periodontitis.

Adult↗

The effect of local delivery of PDGF-BB on attachment of human periodontal ligament fibroblasts to periodontitis-affected root surfaces--in vitro.

BACKGROUND/AIMS: The purpose of this study was to determine at what concentration does platelet-derived growth factor-BB (PDGF-BB) provide for optimal stimulation of human periodontal ligament fibroblasts (PDL) to adhere to periodontitis affected root surfaces. METHOD: 80 root dentine specimens were prepared from extracted periodontally diseased teeth obtained from patients ranging in age between 35 to 60 years. The root dentine specimens were associated with the subgingival area opposing the periodontal pocket for each extracted tooth. 10 healthy root dentine specimens were obtained from teeth extracted for orthodontic reasons and served as controls. The specimens were distributed into 9 groups (10 specimens in each). In group 1, PDL fibroblasts were cultured on the specimen surface of a diseased treated control. In group 2, PDL fibroblasts were cultured on the specimen surface of a healthy control. In groups 3 to 9, PDL fibroblasts were cultured on a pre-treated specimen surface with concentrations ranging from 5, 10, 20, 50, 100, 200 and 300 ng/ml PDGF-BB, respectively. After 24 h incubation, the media were removed, specimens were fixed, processed for SEM viewing and photographed at 750x. Fibroblast adherence was measured by counting number of cells within a standard test area and cell morphology was scored. RESULTS: Findings suggest dentine specimens pretreated with 5, 10 and 20 ng/ml PDGF-BB were not significantly different in number of adherent cells from the diseased treated control. However, at concentrations of 50, 100, 200 and 300 ng/ml, a highly significant increase in number of adherent fibroblasts was detected when compared to the diseased treated control. At these concentrations, the cell morphology was comparable to that of the healthy control. CONCLUSIONS: PDGF-BB in concentrations equal to or greater than 50 ng/ml demonstrates a significant stimulation of PDL cells adherence to periodontal diseased root surfaces. Since the higher concentrations resulted in similar effects as obtained by 50 ng/ml, it may therefore be considered that this concentration provides for optimal stimulation of human periodontal ligament fibroblasts (PDL) to adhere to periodontitis-affected root surfaces.

Adult↗

Regulation of matrix metalloproteinase production by cytokines, pharmacological agents and periodontal pathogens in human periodontal ligament fibroblast cultures.

Matrix metalloproteinases (MMPs). produced by both infiltrating and resident cells of the periodontium, play a role in physiologic and pathologic events. It is recognized that an imbalance between activated MMPs and their endogenous inhibitors leads to pathologic breakdown of the extracellular matrix during periodontitis. To date, little is known about the regulation of MMP synthesis and secretion in human periodontal ligament fibroblasts (PDLFs). The purpose of this study was to examine the effects of cytokines, pharmacological agents (protein synthesis inhibitor and protein kinase C inhibitors) and predominant periodontal pathogens (Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis) on MMP production in human PDLFs using gelatin zymography. The gelatin zymograms revealed that the main gelatinase secreted by human PDLFs migrated at 72 kDa and represents MMP-2. Minor gelatinolytic bands were also observed at 92 kDa regions that correspond to MMP-9. We found that A. actinomycetemcomitans, P. gingivalis and IL-1alpha can elevate MMP-2 secretion in human PDLFs. These results indicate that periodontal pathogens and inflammatory cytokines play an important role in tissue destruction and disintegration of extracellular matrix in periodontal diseases. Thus, activation of MMPs may be one of the distinct host degradative pathways in the pathogenesis of periodontitis. In addition, H7, staurosporine, cycloheximide and TGF-beta could suppress MMP-2 production. Agents that target protein synthesis or the protein kinase C pathway in human PDLFs inhibit MMP-2 production, and such inhibition may contribute to the pathogenesis of periodontal inflammation. Taken together, these findings suggest a possible new therapeutic approach, involving the use of drugs that modify host-response mechanisms to suppress or inhibit MMP-mediated tissue destruction.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

[Adjuvant antibiotic therapy as a 2-step treatment concept in early-onset periodontitis: a strategy for eradication of bacteria that cause periodontitis].

BACKGROUND AND OBJECTIVE: The periodontal region is a source of gram-negative bacterial infection. The pathogens involved have recently also been demonstrated in atheromatous plaques. They may increase the risk of myocardial infarction. In this study a strategy for eradicating periodontal bacteria and thus healing in patients with periodontal pockets and advanced destruction of alveolar bone was examined. PATIENTS AND METHODS: Initial periodontal status was documented in 36 patients with periodontitis (24 women, 12 men) who were then randomly assigned to one of three groups. Those in two of the groups were given either metronidazole or doxycycline orally as adjuvant treatment, while the third group received no antibiotics. Patients in all groups were treated according to a two-step procedure. In step 1, extensive supra- and subgingival plaques and concrements were removed. In step 2, root debridement and/or closed curettage of all pockets was undertaken in one visit, and the antibiotic given to the patients in groups 1 and 2. Results were assessed 3 weeks after the first step and 6 months, 2 and 4 years after step 2. RESULTS: The initial examination at 3 weeks revealed significant changes in all three groups with regard to the incidence of plaque and sulcus bleeding, but not regarding probing depth and attachment level. However, there were significant changes in probing depth and attachment level in all groups after step 2. Periodontal attachment was significantly improved at 2 and 4 years in the patients on metronidazole, but not those on doxycycline or no antibiotics. The greatest decrease in bleeding tendency was recorded in the metronidazole group. This group also had the greatest gain of new alveolar bone compared with the other two groups. Complete eradication of Porphyromonas gingivalis and Actinobacillus (Hemophilus) actinomycetemcomitans, important pathogenic bacteria that may have an atherogenic action, was obtained only in patients on metronidazole. CONCLUSION: The tissue-sparing two-step procedure brought about good clinical and radiological results, which can be significantly bettered by the addition of metronidazole, achieving eradication of pathogens involved in periodontal disease.

Administration, Oral↗

Effect of periodontal therapy on spontaneous lymphocyte response and neutrophil chemotaxis in localized and generalized juvenile periodontitis patients.

The etiology and pathogenesis of juvenile periodontitis may involve dysfunctions of the host response. In particular, the neutrophil and the lymphocyte have been implicated in the disease. The purpose of the present study was to examine the in vitro spontaneous lymphocyte response and neutrophil chemotaxis in populations of localized juvenile periodontitis (LJP) and generalized juvenile periodontitis (GJP) patients and age- and sex-matched healthy subjects (HS). These laboratory values were also evaluated immediately following and 1 year after periodontal therapy. The results show that spontaneous lymphocyte responses reflecting the autologous mixed lymphocyte reaction (AMLR) are depressed for GJP patients. The decreased AMLR in the GJP group appears to represent an abnormal T-cell function which may reflect activity of the periodontal lesion. LJP patients have an increased AMLR response, although it was not statistically significant. 1 year following active periodontal therapy, spontaneous lymphocyte responsiveness returned to normal in most GJP patients. The increased spontaneous lymphocyte responsiveness of LJP patients was not changed either immediately following active periodontal therapy or 1 year later. LJP and GJP patients exhibited a neutrophil chemotaxis defect when compared to cells from HS. This neutrophil defect was still observed 1 year following active therapy.

Adolescent↗

Periodontal disease related to diabetic status. A pilot study of the response to periodontal therapy in type 1 diabetes.

Variation in the periodontal health status and the response to oral hygiene education, scaling and root planing were studied in 36 subjects with type-1 diabetes mellitus (DM) and in 10 non-diabetic control subjects. The age range of the subjects was 24-36 years. The diabetic group was divided into 3 subgroups based on the levels of glycosylated hemoglobin (HbAlc) over a 3 year period and the presence of diabetic complications as follows: (D1) subjects with good metabolic control and no complications (n=13), (D2) subjects with varying metabolic control with/without retinopathy (n=15) and (D3) subjects with severe diabetes, i.e., with poor long-term control and/or multiple complications (n= 8). Clinical measurements (plaque, subgingival calculus, probing pocket depth, bleeding after probing and clinical attachment level) were performed at the baseline and 4 weeks and 6 and 12 months after periodontal therapy. The between-group comparisons were made using the Student t-test and ANOVA. Based on the plaque scores, the oral hygiene status was similar in all groups during the whole study. No statistically-significant differences in the periodontal health status could be found between the diabetic group as a whole and the non-diabetic controls at any examination. The level of periodontal health of the diabetics with good control and no complications (D1) and those with moderate control with/without retinopathy (D2) was on the same level with that seen in the non-diabetic controls. Our findings of the significantly higher extent of al > or =2 mm at the baseline and the fast recurrence of pd > or =4 mm during the longitudinal study in diabetic subjects with poor metabolic control and/or multiple complications (D3) indicate increased periodontal breakdown as a complication of DM in these subjects. To be able to assess the periodontal prognosis and the need for periodontal therapy on an individual basis,the clinical practitioner should be well aware of the diabetic status of his/her patients.

Adult↗

Identification of polymorphonuclear leukocyte collagenase and gelatinase activities in mouthrinse samples: correlation with periodontal disease activity in adult and juvenile periodontitis.

In previous studies, elevations in the levels of active and latent collagenase in gingival crevicular fluid (GCF) have been correlated positively with periodontal disease activity. To provide a simple diagnostic approach for testing collagenolytic activity, the feasibility of using a 3.0 ml water mouthrinse to collect GCF simultaneously from all sites in the mouth was assessed. Patients with adult periodontitis (AP, n = 23) and local juvenile periodontitis (LJP, n = 7) were sampled before periodontal therapy and some (12 AP, 4 LJP) were also assessed longitudinally after scaling and root planing, administration of antibiotics, and following periodontal surgery. Healthy patients (n = 19) were used as controls. The levels of active collagenase, procollagenase, and collagenase inhibitor activity were determined by functional assays and quantitated after SDS-PAGE and fluorography. Gelatinase and progelatinase were assayed by enzymography on gelatin-substrate gels. Active collagenase levels were found to be significantly higher (14- to 20-fold) in AP and LJP patients compared to controls, whereas matrix metalloproteinase activity was not detected in mouthrinses from edentulous patients. Collagenase inhibitor levels were generally low in all groups of subjects tested. Following clinical treatment the levels of active collagenase and gelatinase were reduced; the reduction was significant for active collagenase after tetracycline treatment and scaling in LJP patients. Of the clinical indices recorded (gingival index, plaque index, and pocket depth) there were no significant correlations with enzyme activity but similar trends were observed between the changes in active collagenase and gingival index. In patients with untreated periodontal disease, collagenase occurred predominantly in the active form. N-ethylmaleimide (NEM) and p-aminophenylmercuric acetate (AMPA) were equally effective as activators of the latent collagenase, indicating that the collagenase was derived from PMNs, which were also the source of gelatinase. The results of these studies indicate that measurement of active collagenase and gelatinase in mouthrinse samples is potentially useful in the diagnosis and assessment of periodontal disease activity.

Adolescent↗

Effects of destructive periodontitis, induced by diet, on the mechanical properties of the periodontal ligament of the mandibular first molar in golden hamsters.

To examine progressive changes in the mechanical properties of the periodontal ligament in the hamster mandibular first molar with experimental periodontitis--induced by feeding a high-carbohydrate diet--load-deformation curves obtained by extracting the tooth from its socket in the dissected jaw were analyzed. The maximum shear load, elastic stiffness and failure energy in shear in the experimental groups decreased significantly during the experimental period. On the other hand, significant differences in the maximum deformation were not found between the experimental and the relevant control groups. Radiographic and histological observations showed that the alveolar bone loss and destruction of the periodontal tissues occurred at the cervical region of the tooth in the experimental animals at 8 and 12 weeks after the start of the experiment. It is suggested that the reduction of the mechanical strength of the periodontal ligament in the experimental animals may be due to the alveolar bone loss, destruction of the periodontal tissues at the cervical region--particularly on the lingual aspect--followed by a decrease in the surface area of the ligament. It is also suggested that degenerative changes in the remaining periodontal ligament occurred in hamsters with periodontal disease, causing a reduction in the mechanical strength of the ligament.

Alveolar Bone Loss↗