In vivo early human dental plaque formation on different supporting substances. A scanning electron microscopic and bacteriological study.

Different studies have shown that various substances may have an influence on early human dental plaque formation. The purpose of the present study was to compare on tooth substances and supporting prosthetic materials the amount of plaque deposition by SEM and the quantity of selected bacteria using anaerobic culturing techniques. 5 bridges, replacing a missing molar or premolar, were incorporated in 3 patients. In the midbuccal area of each pontic, a semi-precision attachment was placed allowing the insertion of the following test facings: enamel, dentine, non gamma 2-amalgam, alloys of 85% and 55% gold, silver-palladium, chrome-cobalt, chrome-cobalt-titanium, and ceramic. For each material, 2 facings were fabricated. After 4 and 24 hours in situ, bacteriological samples were taken and processed for further identification. After a 2nd period of 4 and 24 hours in situ, the same facings were carefully removed and prepared for SEM-examination. All 4-hour specimens exhibited various areas covered by plaque, the amount of which varied with the different supporting substances. The very smooth surfaces (e.g., gold) harbored sparse deposits, while the rougher (e.g., amalgam) were covered by more plaque. After 24 hours of plaque development, an increase in the number of micro-organisms was noted for all the specimens. After 4 and 24 hours of plaque accumulation, no specific trends suggesting a preferential colonization on the different substances were observed. This study has shown that the amount of early deposits on different substances seems to be related to the degree of their surface roughness, while plaque formation was qualitatively similar.

Changes in subgingival microbiota during puberty. A 4-year longitudinal study.

It was the purpose of the present investigation to monitor the composition of the subgingival microbiota at selected sites in individuals passing through puberty and to correlate observed changes with the development of pubertal maturation. Between the ages of 11 and 14 years, pubertal and skeletal maturation was monitored annually in 22 boys and 20 girls. During this time, subgingival microbial samples were taken every 4th to 5th month (10 times in 4 years) mesially of the upper first molars. High values in total bacterial counts were reached after the onset of puberty, followed by a decrease towards the end of the observation period. The frequency of detection of Actinomyces odontolyticus and of Capnocytophaga sp. increased with time. The frequencies of other selected species, specifically of black pigmenting Bacteriodes sp. were not found to increase when tested by linear and quadratic models of time trend. However, a statistically significant rise in the frequency of detecting B. intermedius and B. melaninogenicus was noted in the initial pubertal phase identified by the onset of testicular growth in boys (p = 0.05). A significant relationship also existed between testes growth and increase of A. odontolyticus (p less than 0.01). In girls, a similar increase was obtained for A. odontolyticus when studied in relation to the Tanner scores for breast development (p less than 0.01). The changes observed in the subgingival microbiota during puberty may be related to the development of gingivitis, which was demonstrated by a higher tendency for gingival bleeding during the course of the pubertal maturation process.

Microbial changes associated with the development of puberty gingivitis.

In this study, longitudinal changes in the composition of the subgingival microbiota of children between the ages of 11 and 14 and their association with changes of clinical parameters describing gingival health were investigated. During 4 years, subgingival microbial samples were taken in 22 boys and 20 girls 10 times. At the same time the gingival bleeding tendency was recorded by the Papillary Bleeding Index (PBI). A total of 840 samples was evaluated using darkfield microscopy and anaerobic culturing on non-selective and selective media. Children, who developed a marked and sustained increase in mean PBI scores (n = 21), had higher frequencies and mean proportions of spirochetes and Eikenella corrodens than children without pronounced puberty gingivitis (p less than = 0.05). The mean proportion of Actinomyces viscosus was also higher in these children (p less than = 0.05). Among the species discriminated, only Capnocytophaga sp. were found at a higher rate in samples taken immediately before a rise of PBI (p less than = 0.05). The detection frequencies of black-pigmented Bacteroides (particularly B. intermedius) increased later, and were significantly elevated after the establishment of a high bleeding tendency (p less than = 0.05). These findings implicate Capnocytophaga sp. in the initiation of puberty gingivitis, whereas the increased presence of Bacteroides may reflect a change in the subgingival environment secondary to increased bleeding.

Reproducibility of microscopic and cultural data in repeated subgingival plaque samples.

In association studies, micro-organisms can only be recognized as suspects for playing a major rôle in the development of a pathological environment, if their destructive action goes along with a marked proportional increase of their numbers or if their first detection can be related to the clinical onset of the disease. Limitations in the reproducibility of repeated samples have to be taken into account, when changes of the microbial composition of subgingival environments are to be studied, and when local clinical changes are to be related to shifts in the composition of the pertaining microbiological compartment. To study reproducibility, a total of 109 sites was sampled repeatedly with sterile paperpoints at an interval of 7 to 10 days in 24 patients suffering from periodontal disease and 12 edentulous patients wearing successful and failing osseointegrated titanium implants. Using continuous anaerobic techniques, the samples were cultured on nonselective and selective media and were studied by darkfield microscopy. Both the intertest-agreements of frequencies of detection (kappa-statistics) as well as the discrepancies of proportions of bacterial groups and selected bacterial species were determined. The standard deviation of proportional differences between first and second samples ranged between 6.4% (fusiform organisms) and 17.2% (coccoid cells) for darkfield parameters, between 4.3% (B. melaninogenicus on ETSA/Kana.) and 14.0% (B. gingivalis on ETSA/Kana.) for selected bacterial species and between 6.9% (gram-negative anaerobic cocci) and 24.0% (gram-positive facultative cocci) for bacterial groups classified according to gram stain characteristics and atmospheric growth conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Gingival health and gingivitis development during puberty. A 4-year longitudinal study.

The purpose of this investigation was to follow the development of the gingival conditions during puberty and to correlate oral clinical parameters with chronological age as well as with parameters used for the determination of the pubertal development. In 22 boys and 20 girls pubertal and skeletal development, as well as plaque index (PlI) and gingival index (GI) were monitored at 1-year intervals between the ages of 11 and 15 years. During this time, the papillary bleeding index (PBI) was assessed 10 times in all interdental spaces of the dentition. The bleeding tendency, represented by whole mouth mean PBI values, as well as the % of bleeding interdental sites, was found to increase significantly with the start of the pubertal phase. It reached a peak value after 1-5 years in 35% of the children. A significant trend of decrease was noted after the age of 14 years in boys and girls. In boys, mean PBI and the % of interdental sites with bleeding were correlated with testes growth, in girls with the Tanner index for secondary sex characteristics (breast development). PlI and GI, which were only recorded annually, did not show a significant trend of increase or decrease.

Treatment of recurrent periodontal disease by root planing and Ornidazole (Tiberal). Clinical and microbiological findings.

The purpose of this study was to evaluate the use of Ornidazole as an adjunct to root planing in the therapy of patients suffering from recurrent periodontal disease. In 10 individuals who had previously been treated with scaling, root planing and periodontal surgery and who had followed a regular maintenance program including recall visits every 3-5 months for 1-7 years, 2 sites with recurrent periodontitis and 1 shallow site were selected. Reinfected sites had a record of losing clinical attachment of more than 3 mm since the completion of initial therapy, were bleeding upon probing and had a mean pocket probing depth of 7.85 +/- 1.31 mm. They had been reinstrumented several times by a registered dental hygienist, when clinical signs of recurrence of disease had appeared and the root surfaces were judged to be smooth and free of deposits. Clinical parameters were recorded and microbial samples were collected twice prior to retreatment. Then, 500 mg Ornidazole, to be taken twice a day for 10 days, was administered, and the whole dentition was thoroughly scaled and root planed. At day 10 as well as 2, 5, 8 and 11 months thereafter, samples were again obtained. At baseline, reinfected sites showed over 20% spirochetes, over 20% motile rods and over 9% fusiform organisms in darkfield preparations of subgingival plaque samples. Culturally, over 1/10 of organisms were identified as black pigmenting Bacteroides and in 18% of all baseline samples collected, B. gingivalis was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined antibiotic (metronidazole) and mechanical treatment effects on the subgingival bacterial flora of sites with recurrent periodontal disease.

5 patients in maintenance, 1-3 years after periodontal therapy who showed sites with reinfected pockets and bleeding despite regular recall visits were selected. Darkfield microscopy from 3 sites in each patient showed an average of 41% spirochetes and 21% motile rods. Probing depths ranged from 7 to 9 mm and loss of clinical attachment from 6 to 13 mm in these sites. The patients were given 3 times 250 mg/day of metronidazole (Flagyl) for 10 days. Darkfield microscopy and microbiological cultures of the subgingival plaque were performed twice prior to the study, at the end of the medication and after 3 weeks, 3 and 6 months. The plaque and gingival indices, probing depth and loss of clinical attachment were recorded. During the medication and at 3 and 6 months, the teeth were scaled and root planed. The samples were obtained with 3 paper points and cultured anaerobically in the glove box on non-selective and selective media and representative bacterial colonies identified by aerobic growth, gram stain and rapid biochemical tests. Presumptive pathogenic micro-organisms including Bacteroides were identified. The % of spirochetes, motile rods and non-motile bacteria were enumerated by darkfield microscopy. The clinical results show that administration of metronidazole and repeated root planing significantly decreased gingival inflammation, probing depth and loss of clinical attachment in reinfected sites. After treatment, these sites harbored significantly less spirochetes and more non-motile bacteria, while motile rods tended to return to baseline levels with time. The combined antibiotic and mechanical therapy resulted in a statistically significant decrease of gram-negative rods, Fusobacteria and Bacteroides gingivalis over 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiological and clinical effects of chlorhexidine digluconate and hydrogen peroxide mouthrinses on developing plaque and gingivitis.

While the ability of chlorhexidine (CHX) to prevent plaque formation and inhibit the development of gingivitis has been well documented in the literature, the therapeutic value of hydrogen peroxide (H2O2) in preventing gingivitis is in dispute. The purpose of this study was to compare the clinical and microbiological effects of an established therapeutic agent, such as chlorhexidine with that of H2O2 in the experimental gingivitis model. Following a period of stringent oral hygiene, 32 subjects were allocated to 1 of 3 treatment groups which were balanced on the basis of their pre-experimental gingivitis scores. The subjects then refrained from any oral hygiene for 21 days. During this period, they rinsed twice a day with either a placebo, 0.12% CHX, or a 1% H2O2 mouthrinse. After 21 days, supragingival and marginal plaque was collected from each subject and assayed for total cultivable microbiota, total facultative anaerobes, facultative Streptococci, Actinomyces, Fusobacterium, Veillonella and Capnocytophaga. At the end of the experimental period, the group rinsing with 0.12% CHX showed 95% reduction in gingivitis incidence, 100% reduction in bleeding sites, and 80% reduction in plaque scores compared to the group rinsing with placebo. Conversely, the group using 1% H2O2 showed a marginal reduction in gingivitis incidence of 15% and a 28% reduction in bleeding sites compared to the placebo group, but no significant reduction in plaque scores. The microbiological results showed that 0.12% CHX was an excellent broad-spectrum antimicrobial agent which significantly reduced the number of both facultative and obligate anaerobes in plaque.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and microbiological effects of fixed orthodontic appliances.

The purpose of this clinical and microbiological study was to evaluate longitudinally the changes occurring in the subgingival microbiota in children following the placement of orthodontic bands in the absence of a prophylactic oral hygiene program. A total of 12 children in the age between 10 and 15 years were selected for the study. The experimental group (E) consisted of 6 subjects scheduled for orthodontic treatment including the placement of fixed appliances. They were seen 1 week before and just prior to the placement of orthodontic bands. The control group (C) involved 6 children in the maintenance phase of orthodontic therapy in which removable retainers were used. All subjects were examined at 3-5 week intervals for a period of 4 months. At each examination, microbiological subgingival plaque samples were collected by means of sterile paper points. Plaque and gingival index scores as well as pocket probing depth at the site of sampling were determined. The microbiological samples were processed using continuous anaerobic culturing techniques and were plated on non-selective and selective media. Differential counts and biochemical characterization of isolates were performed according to the methods described by Kornman and Loesche. Following tooth-banding, an increase in pocket probing depth was observed, while the P1I and GI scores remained unaffected. A statistically significant increase from baseline values (p less than 0.05) was found for the %s of black-pigmented bacteroides, the B. intermedius and A. odontolyticus species, concomitantly with a decrease of the anaerobe/facultative bacteria ratio in the experimental, but not the control sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Bleeding on probing. A predictor for the progression of periodontal disease?

Bleeding on probing (BOP) is a widely used criterion to diagnose gingival inflammation. The purpose of the present retrospective study was to evaluate its prognostic value in identifying sites at risk for periodontal breakdown during the maintenance phase of periodontal therapy. 55 patients who had been treated for advanced periodontitis participated in a recall system for at least 4 years, at regular intervals of 3-5 months. At the start of every appointment, BOP to the bottom of the pocket was registered at 4 sites of every tooth. A random selection of 1054 pockets was made and subdivided into 5 categories according to the incidence of BOP during the last 4 recall appointments. All pockets with a BOP incidence of 4/4 and 3/4 were selected, while only interproximal sites with a BOP incidence of 2/4, 1/4 and 0/4 were chosen. Subsequently, these categories were grouped according to whether or not the attachment level had been maintained from the time prior to the last 4 recall visits. Greater than or equal to 2 mm was defined as loss of clinical attachment. The results indicated that pockets with a probing depth of greater than or equal to 5 mm had a significantly higher incidence of BOP. Patients with 16% or more BOP sites had a higher chance of loosing attachment. Pockets with an incidence of BOP of 4/4 had a 30% chance of loosing attachment. This chance decreased to 14% with BOP of 3/4, 6% with BOP of 2/4, 3% with BOP of 1/4 and 1.5% with BOP of 0/4.(ABSTRACT TRUNCATED AT 250 WORDS)

Cultivable microflora of plaque from full denture bases and adjacent palatal mucosa.

Anaerobic cultural techniques and rapid biochemical identification tests normally employed for periodontal plaque were utilized for the analysis of plaque samples taken from denture bases and corresponding adjacent mucosa. Results were compared with those or more comprehensive microbiological investigations. Forty four samples were obtained from the denture bases and adjacent palatal mucosa of 12 patients wearing full upper dentures. The specimens were then collected in Reduced Transport Fluid and processed in the anaerobic glove box. Samples were plated on Enriched Trypticase Soy Agar (ETSA) and cultured under both aerobic and anaerobic conditions. In addition plaque samples were plated on Sabouraud medium. Facultative bacteria predominated in both denture and palatal plaques. Significantly greater numbers of cocci were recovered in the samples from palatal mucosa. More rods were found in denture plaque. Anaerobes were present in both instances. Among the anaerobes, saccharolytic Bacteroides were identified with the highest frequency, while Veillonella species were present in the greatest quantity. Recovery of yeasts was similar for both ETSA and Sabouraud media incubated aerobically. As has been found in other microbiological studies Candida albicans represented only a minor part of the total cultivable flora.

Periodontal conditions in adolescents with cleft lip, alveolus and palate following treatment in a co-ordinated team approach.

The aim of the present investigation was to evaluate the oral hygiene habits and the periodontal conditions of a group of cleft lip, alveolus and palate patients at the end of a longitudinal multidisciplinary treatment. From a total of 120 patients who had been supervised at the University of Berne, Clinic for Pediatric Surgery for at least 18 years in a co-ordinated team approach, 80 were selected on the basis of availability. Plaque control record (PCR), calculus index (CI), gingival bleeding index (GBI), pocket probing depth (PD), loss of attachment (LA) and furcation involvement were recorded. Using the technique and the ruler described by Schei et al., the radiographic height of the alveolar crest from the cemento-enamel junction was determined. Between the different groups of deformities, no statistically significant differences were found for all the clinical parameters with the exception of the mean PD orally and the mean PD bucally which were shallower in the isolated cleft lip group. These differences were attributed to the long-term orthodontic therapy with fixed appliances. When the PD and the LA at the sites adjacent to the cleft region were compared to two "unaffected" control sites, no statistically significant differences were found, whereas the comparison with the radiographic bone loss showed a statistically significant lower bone height. These results may indicate the presence of a long connective tissue attachment without bony support in the cleft region. As a result of inadequate oral hygiene, the patients with cleft lip, alveolus and palate showed beginning periodontitis with loss of attachment and beginning furcation involvement in most of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)