Chronic treatment with the glucocorticoid receptor antagonist RU486 inhibits diabetes-induced enhancement of experimental periodontitis.

BACKGROUND AND OBJECTIVE: Chronic hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and excessive glucocorticoid hormone release have been associated with diabetes, altered immune responses and increased susceptibility to periodontitis. In the present study we tested the impact of streptozotocin (STZ)-induced diabetes on ligature-induced periodontitis and the effect of subsequent treatment with the glucocorticoid receptor (GR) antagonist, RU486. MATERIAL AND METHODS: A single dose of STZ [45 mg/kg, intraperitoneally (i.p.)] or vehicle was given 10 d before induction of ligature-induced periodontitis and implantation subcutaneously of a drug pellet containing the GR antagonist, RU486, or a placebo pellet. Periodontitis was assessed when the ligatures had been in place for 21 d. Two hours before decapitation all rats received gram-negative bacterial lipopolysaccharide (LPS) (150 µg/kg, i.p.) to induce a robust immune and stress response. RESULTS: Compared with control rats, STZ-treated rats developed significantly more periodontal bone loss, and RU486 treatment of STZ -treated rats significantly inhibited this effect. STZ-treated rats also showed significantly higher levels of the HPA axis-derived hormone, corticosterone, as well as of the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α), but lower levels of the anti-inflammatory cytokines interleukin-10 (IL-10) and transforming growth factor-1beta (TGF-1ß) after LPS stimulation. GR blockade had no statistically significant effects on these measurements in diabetic rats, but tended to enhance the levels of TNF-α and TGF-1ß, and reduce the levels of IL-10 and blood glucose. CONCLUSION: In diabetic subjects, excessive GR activation as a result of chronic high levels of glucocorticoid hormones may alter immune-system responses in a manner that may increase the susceptibility to periodontitis.

Oral treatment with complement factor C5a receptor (CD88) antagonists inhibits experimental periodontitis in rats.

BACKGROUND AND OBJECTIVE: The complement activation product 5a (C5a) is a potent mediator of the innate immune response to infection, and may thus also importantly determine the development of periodontitis. The present study was designed to explore the effect of several novel, potent and orally active C5a receptor (CD88) antagonists (C5aRAs) on the development of ligature-induced periodontitis in an animal model. MATERIAL AND METHODS: Three different cyclic peptide C5aRAs, termed PMX205, PMX218 and PMX273, were investigated. Four groups of Wistar rats (n = 10 in each group) were used. Starting 3 d before induction of experimental periodontitis, rats either received one of the C5aRas (1-2 mg/kg) in the drinking water or received drinking water only. Periodontitis was assessed when the ligatures had been in place for 14 d. RESULTS: Compared with control rats, PMX205- and PMX218-treated rats had significantly reduced periodontal bone loss. CONCLUSION: The findings suggest that complement activation, and particularly C5a generation, may play a significant role in the development and progression of periodontitis. Blockade of the major C5a receptor, CD88, with specific inhibitors such as PMX205, may offer novel treatment options for periodontitis.

Nicotinic acetylcholine receptor activation mediates nicotine-induced enhancement of experimental periodontitis.

BACKGROUND AND OBJECTIVE: Smokers have an increased risk of developing periodontitis as well as showing more rapid progression and resistance to treatment of the disease, but the biological mechanisms are poorly understood. This study was designed to investigate putative biological mechanisms by which nicotine may enhance the susceptibility and thus the course of periodontitis in an animal model. MATERIAL AND METHODS: Ligature-induced periodontitis was applied in periodontitis-susceptible Fischer 344 rats. The animals were either given daily intraperitoneal injections of the nicotinic acetylcholine receptor antagonist mecamylamine (1 mg/kg) 45 min before subcutaneous injections in the neck skin of nicotine (0.8 mg/kg), or treated with the same amount of saline intraperitoneally and nicotine subcutaneously, or treated with mecamylamine and saline. Control animals received intraperitoneal and subcutaneous injections of saline only. Periodontal bone loss was assessed when the ligatures had been in place for 3 wk. Two hours before decapitation, all rats received lipopolysaccharide (LPS; 100 microg/kg, intraperitoneally) to induce a robust immune and stress response. RESULTS: Compared with saline/saline-treated control animals, saline/nicotine-treated rats developed significantly more periodontal bone loss, and LPS provoked a significantly smaller increase in circulating levels of the cytokines tumour necrosis factor-alpha, transforming growth factor-1beta and interleukin-10. Mecamylamine pretreatment of nicotine-treated rats abrogated the increased periodontal bone loss and the LPS-induced decrease in tumour necrosis factor-alpha, but had no significant effects on the levels of transforming growth factor-1beta and interleukin-10, or the stress hormone corticosterone. CONCLUSION: The results indicate that nicotine enhances the susceptibility to periodontitis via nicotinic acetylcholine receptors, which may act by suppressing protective immune responses through the cholinergic anti-inflammatory pathway.

Nicotinic acetylcholine receptor activation mediates nicotine-induced enhancement of experimental periodontitis.

BACKGROUND AND OBJECTIVE: Smokers have an increased risk of developing periodontitis as well as showing more rapid progression and resistance to treatment of the disease, but the biological mechanisms are poorly understood. Our objective was to investigate putative biological mechanisms by which nicotine may enhance the susceptibility and thus the course of periodontitis in an animal model. MATERIAL AND METHODS: Ligature-induced periodontitis was applied in periodontitis-susceptible Fischer 344 rats. The animals were given daily intraperiotonal (i.p.) injections of the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine (1 mg/kg) 45 min before subcutaneous (s.c.) injections in the neck skin with nicotine (0.8 mg/kg), or treated with the same amount of saline i.p. and nicotine s.c., or with mecamylamine and saline. Control rats received i.p. and s.c. injections of saline only. Periodontal bone loss was assessed when the ligatures had been in place for 3 weeks. Two hours before decapitation, all rats received lipopolysaccharide (LPS; 100 microg/kg, i.p.) to induce a robust immune and stress response. RESULTS: Compared with saline/saline-treated control rats, saline/nicotine-treated rats developed significantly more periodontal bone loss, and LPS provoked a significantly smaller increase in circulating levels of the cytokines tumour necrosis factor alpha (TNF-alpha), transforming growth factor 1beta (TGF-1beta) and interleukin-10 (IL-10). Mecamylamine pretreatment of nicotine-treated rats abrogated the increased periodontal bone loss and the LPS-induced TNF-alpha decrease, but had no significant effects on the levels of TGF-1beta and IL-10, or the stress hormone corticosterone. CONCLUSION: The results indicate that nicotine enhances susceptibility to periodontitis via nAChRs, which may act via suppressing protective immune responses through the cholinergic anti-inflammatory pathway.

Association between detection of oral Actinobacillus actinomycetemcomitans and radiographic bone loss in teenagers. A 4-year longitudinal study.

The aim of the present study was to assess a possible association between radiographic bone loss and presence of Actinobacillus actinomycetemcomitans on the site and subject level over time. Forty-six teenagers with registered radiographic bone loss and 8 controls participated in the study, which began in 1984. In 1986 and 1988 new sets of bite-wing radiographs were obtained and examined for bone loss. Subgingival plaque was sampled from both diseased and contralateral healthy sites in the same individual. Only 15 of the 46 originally diseased sites persisted with bone loss in 1986, and 60% of these sites harbored A. actinomycetemcomitans. Of the 31 "healed" sites, 29% contained A. actinomycetemcomitans. The difference was statistically significant at P less than 0.05. Six of the contralateral healthy sites had developed bone loss during these 2 years and 50% of them contained A. actinomycetemcomitans, while 35% of the remaining contralateral sites harbored A. actinomycetemcomitans. The difference was not statistically significant (P greater than 0.05). The difference between patients with and without persistent bone loss regarding presence of A. actinomycetemcomitans was statistically significant in 1986; however, none of the observed differences were statistically significant in 1988. A. actinomycetemcomitans was found 2 to 3 times more frequently in patients with radiographic bone loss at all examinations than in "healthy" subjects. Detection of A. actinomycetemcomitans on the site level appeared to be a poor predictor of future radiographic bone loss.

Chlorhexidine use after two decades of over-the-counter availability.

Chlorhexidine (CHX) is a compound with plaque-inhibiting effects and available only by prescription in the United States. In Norway, however, CHX has been dispensed over-the-counter for over 20 years, and this study was undertaken to evaluate dentists' perceptions regarding its indications, usefulness, and side effects. A written questionnaire was sent to a sample of 10% of dentists registered in Norway, 78% of whom (354) responded. Additionally, representatives from 2% of all dental practices in Norway were contacted by telephone. Fourteen percent (14%) of the respondents reported that they never recommended CHX to their patients. Among those recommending the compound, 85% used it frequently after surgical periodontal procedures; 74% when treating acute gingivitis; 57% following oral surgery in general; and 35% during non-surgical periodontal therapy. It was used also as an adjunct to other treatment routines. Seventy-three percent (73%) reported frequent use of CHX when treating stomatitis and 54% in herpes simplex infections. As to side effects, 77% of the dentists indicated that staining of teeth, restorations, and the tongue was a major concern to patients; 12% reported inconveniences due to the bitter taste; and 6% reported other disturbances such as dryness of the mouth and development of oral ulcerations. The majority (94%) of the dentists recommended mouth rinsing, whereas 6% recommended a gel form. Only 4% of the dentists recommended rinsing with a patient-diluted 0.1% concentration, whereas 96% recommended the standard 0.2% formulation; 88% recommended using CHX mouthwash twice a day or more often.(ABSTRACT TRUNCATED AT 250 WORDS)

Gingival fluid flow after gingivectomy related to mechanical or chemical plaque control.

The effects of mechanical tooth cleaning and 0.2% chlorhexidine mouthrinses on healing after gingivectomy were compared in 8 patients by means of a "split mouth" technique. The experiment began after periodontal pack removal on day 7. Gingival fluid was sampled immediately before and on days 14, 21, 28, 35 after gingivectomy. The results showed that mechanical and chemical plaque control were equally effective in promoting healing after gingivectomy as evaluated by gingival fluid measurements.

Incidence of early periodontitis in a group of young individuals during 8 years: associations with selected potential predictors.

The aim of the present study was to assess the incidence of early radiographic bone loss in a birth cohort over 8 years and to assess possible associations between incidence of bone loss and reported dental behavior, ethnic background, and previous orthodontic treatment. In a case control study comprising a proportion of the study population, the detection of black pigmented Bacteroides and Actinobacillus actinomycetemcomitans and their association with early radiographic bone loss was assessed. At the beginning of the study in 1984, there were 2,767 subjects. In 1992 sets of bite-wing radiographs were obtained from 215 subjects, who also filled out a questionnaire concerning their present and past dental behavior, ethnic background, and orthodontic treatment. Radiographic alveolar bone loss was recorded if the distance from the cemento-enamel junction to the alveolar crest exceeded 2 mm. Thirteen subjects (6%) showed new sites with bone loss over the 8-year period. Subgingival plaque was sampled from these 13 subjects and from 13 control subjects. None of the independent variables could be associated with the observed incidence of radiographic bone loss in this cohort, with the possible exception of the presence of A. actinomycetemcomitans which was detected in about 50% of the new sites with bone loss.

Clinical and microbiological effects of adjunctive antibiotics in treatment of localized juvenile periodontitis. A controlled clinical trial.

The aim of this study was to assess the clinical and microbiologic effects of the combination of amoxicillin and metronidazole therapy as an adjunct to mechanical treatment in the management of localized juvenile periodontitis. Twenty-five localized juvenile periodontitis (LJP) patients from a Brazilian population were randomly allocated into an experimental group receiving mechanical treatment and antibiotics, and a control group receiving mechanical treatment and placebo. Clinical and radiographic assessments, as well as microbiologic sampling for Actinobacillus actinomycetemcomitans, were performed at baseline and one year after the end of the treatment. At the termination of the study A. actinomycetemcomitans could be isolated from the oral cavity of all patients in the control group who harbored the bacterium at baseline and in 4 out of 8 patients in the experimental group. Both treatment modalities resulted in significant benefit on an individual basis. The experimental group, however, displayed better results than did the control group regarding gingival index (GI), probing depth (PD), clinical attachment level (CAL), and radiographic analysis of crestal alveolar bone mass, but not with respect to plaque index (PI). No serious adverse effects of the antibiotic treatment were observed in the present study.

Prevalence of oral soft and hard tissue lesions related to mechanical toothcleansing procedures.

The prevalence of oral soft and hard tissue lesions related to mechanical oral hygiene procedures was recorded and correlated to toothbrushing habits and oral hygiene status in two selected samples. Fifty-one percent of 533 persons examined exhibited gingival retractions and 45% had wedge-shaped defects in the cervical area of one or several teeth. Both types of lesions were often seen in the same area, indicating a common etiologic factor. The subjects with a good oral hygiene status, as well as those who brushed more than twice daily, showed a high frequency of lesions. The various toothbrushing techniques did not, however, seem to influence the development of such lesions in the present material. Subjective symptoms were reported in a few cases only.

Validity of CPITN's hierarchical scoring method for describing the prevalence of periodontal conditions.

CPITN has been a frequently used index in periodontal epidemiology during the last decade. It was originally designed to describe treatment needs in populations. For this purpose, it was decided to record only the worst periodontal condition around each index tooth. Such a recording procedure can be regarded as a hierarchical scoring method. Recently, CPITN has been used and recommended for describing the prevalence of periodontal conditions. For this purpose, the index should give a valid estimate of the true periodontal conditions of the index tooth, and not only a recording of the worst condition. The aim of the present study was to test whether the hierarchical assumption of CPITN concerning treatment needs was valid for describing the prevalence of periodontal conditions in a Scandinavian population. The study population comprised 3330 persons from a rural and an urban area in the county of Trøndelag, Norway. The clinical recording was carried out so that it was possible to analyze the indicators both hierarchically and non-hierarchically. The results showed that nearly all the CPITN indicators scored hierarchically gave a correct estimate of the prevalence of bleeding in the population. CPITN codes 3 and 4 overestimated the prevalence of calculus. The degree of overestimation varied by age and tooth type. Most overestimation of calculus occurred on molar teeth with pockets 3.5-5.5 mm and for individuals 13-14 yr of age. There was almost no overestimation of calculus for those aged 65 yr and above.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the effectiveness of three different methods in detection of changes in gingivitis in the primary dentition.

The pattern of distribution and development of gingivitis is different in children and adults. Also the anatomy in the primary dentition is different from that in the permanent dentition. Indices to measure gingival inflammation and changes in this condition have been designed for the permanent dentition and may not necessarily perform adequately in the primary dentition. The purpose of the present study was to assess the association between indices commonly used in adults and to compare their ability to detect changes in gingivitis in children. The correlation between the Gingival Index and percent bleeding units (scores 2 and 3) was r = 0.93, while provoked bleeding from the interdental area correlated only weakly with the two. However, the non-bleeding papilla index seemed to more effectively detect changes in the gingival condition induced by professional cleaning. Since gingivitis usually is less severe in the primary dentition than in the permanent dentition, it may be of importance to use an index with high sensitivity in studies where effect of interventions is to be evaluated in children.

Changes in radiographic bone level in orthodontically treated teenagers over a 4-year period.

In 1984 the prevalence of subjects with radiographic bone loss was assessed in all 14-year-old schoolchildren in Oslo (n = 2767). An overrepresentation of subjects with bone loss was found among those undergoing orthodontic treatment. The aim of the present study was to assess the effect of orthodontic treatment on the prevalence and incidence of radiographic bone loss during the following 4-yr period. Bitewing radiographs from 1984, 1986, and 1988 of a sample of 438 subjects from the original population constituted the study material. Bone loss was recorded if the distance from the alveolar crest to the cementoenamel junction exceeded 2 mm. 111 subjects (25.3%) had received orthodontic treatment. In 1984, 18 of them (16.2%) exhibited bone loss. The corresponding figure for the 327 non-treated children was 14 (4.3%). The incidence of subjects with new tooth sites with bone loss among those with a record of previous orthodontic treatment was 1.1% and 3.2% in the periods 1984-86 and 1986-88, respectively. Among those who had never received such treatment the incidence figures were 3.2% in the period 1984-86 and 2.0% in the last period. The results indicated that the majority of the bone loss observed during or immediately after termination of orthodontic treatment was transient in nature.

Application of the Community Periodontal Index of Treatment Needs (CPITN) in a population of young Brazilians.

Recently WHO has launched an index for assessing the periodontal treatment needs of a population in terms of resources required. This Community Periodontal Index of Treatment Needs was applied in 308 Brazilian 15-yr-old schoolchildren from a population with a high prevalence of periodontitis. The results showed that all subjects needed some kind of care. Totally, 4133 time units were required. Most of the time needed was for motivation and instruction in oral hygiene, and scaling. Several individuals assigned for complex treatment due to pockets deeper than 5.5 mm showed no signs of radiographic bone loss, and in the cases with bone loss, the lesions were few and small. The CPITN therefore seemed to overestimate the need for treatment in this young population. To overcome this problem, it was suggested that complex treatment should not be included in planning of systematic periodontal care for young populations, and that subjects with true periodontal lesions should be given priority in community programs.

Comparison between standardized periapical and bitewing radiographs in assessing alveolar bone loss.

Readability and alveolar bone level were compared in 455 sets of standardized radiographs each consisting of four periapical (PA) and two bitewing (BW) films. BW radiographs showed significantly higher proportions of unreadable sites in the canines and the mesial surface of first premolars (P less than 0.0001), while PA radiographs exhibited significantly higher proportions of unreadable sites in the distal surface of second molars (P less than 0.0001). Alveolar bone level was assessable in a total of 10016 sites, and the comparison showed identical readings in 82% of the sites. In the maxilla, a significantly higher proportion of sites exhibited larger bone loss measurements (P less than 0.0001) and more sites with significantly higher mean values (P less than 0.005) in BW than in PA films. Mandibular sites showed the opposite trend. The majority of the sites revealed a Pearson's correlation coefficient (r) ranging between 0.60 and 0.82. No significant difference between mean bone loss measurements in the two types of radiographs for all the sites was found. It was concluded that the two radiographic techniques may be used interchangeably in epidemiologic studies.

Study of tooth loss in an adolescent Brazilian population.

Data concerning tooth loss in developing countries may indicate the dental health status in young people and serve as baseline data for evaluation of future dental health programs. The study population consisted of 304 schoolchildren (145 males, 159 females) from Belo Horizonte, M.G. Brazil. The mean age was 14.5, ranging from 13 to 16 yr. The number of teeth already lost and teeth indicated for extraction were assessed from two posterior bitewing radiographs and one frontal color photo which were obtained from all participants. The results showed that 2/3 of the studied population had lost one or more permanent teeth. The average number of missing teeth was 1.8 in both males and females. Of the various teeth, the mandibular first molars had most frequently been lost. Differences between the sexes concerning amount and pattern of lost teeth were small.

Effect of two preventive programs on oral health knowledge and habits among Brazilian schoolchildren.

The effect upon dental health knowledge and dental health behavior of a comprehensive and a less comprehensive preventive program was compared in a 3-yr follow up study. The comprehensive program included active participation of the students and parental involvement. The study group consisted of 186 Brazilian schoolchildren 13 yr of age at the start of the program. A reference group from another school of similar socioeconomic level was included in the analyses. The data were collected from questionnaires filled in by the children under surveillance after the completion of the program. Significant differences in knowledge as well as in reported behavior were observed. The children enrolled in the comprehensive program in general scored higher in dental health knowledge than did those in the less comprehensive program. However, the latter group of children seemed to have acquired more correct knowledge during the period than had the control and reference children. Similar results were obtained concerning reported dental health behavior.

CPITN as a basic periodontal examination in dental practice.

Diagnosis of a disease or condition in an individual may be defined as a conclusion which is reached following an evaluation of clinical, radiographic, laboratory and anamnestic information obtained by examination. No index designed for epidemiological purposes can be substituted for the careful process of reaching a diagnosis in an individual. However, in spite of arguments against its validity in this respect, CPITN has been suggested as a simple and quick screening tool for use in general dental practice. Several studies support this notion and that CPITN may assist in: assessing the goals for treatment, estimating the time and cost requirements, evaluating the results, and being useful in communication between dentists, specialists and auxiliary personnel. Modifications of CPITN for use with individuals have been launched in several countries which dentists and periodontists find useful and acceptable.

The assessment of needs for periodontal treatment.

The purpose of epidemiology is 'to guide the administration in the provision of health services' (MacMahon and Pugh, 1970). The provision of systematic treatment of periodontal disease has been hampered by the lack of a suitable system for calculating manpower and costs involved in the treatment of population groups. Recently, the Periodontal Treatment Need System (PTNS) has been suggested to meet with these requirements (Johansen, Gjermo & Bellini, 1973: Bellini and Gjermo, 1973). The principles of the system are explained and discussed. Moreover, it is emphasized that the prevention of periodontal disease as well as caries should be the paramount goal of the public dental health services. A possible method for early diagnosis and preventive treatment of high risk subjects is suggested.

The clinical trial in multidisciplinary research.

Dental research has developed along two separate paths. Epidemiological studies can only indicate a cause-disease relationship while laboratory experiments can only be applied to the human situation as a working hypothesis. The final solution can only be arrived at by setting up controlled studies in man, though there are limitations on the possibility of control of some variables in human studies. Experimental studies on the formation of pellicles and plaque are described as examples of the use of clinical trials to bridge the gap between basic research and epidemiological data. The ideal model for dental research would involve the identification of a clinical problem and its subdivision into small biological units which could be studied in the laboratory in order to develop working hypothesis. An in vivo model would then be devised to test the hypotheses and finally they would be applied in a well controlled trial.