Transmission and colonization of Actinobacillus actinomycetemcomitans in localized juvenile periodontitis patients

Effectiveness of single use over multiple use toothbrushes on negative oral microflora of plaque

Context:

Role of toothbrush in decreasing oral microflora.

Aims:

To evaluate the effectiveness and compare the negative oral microbial flora of dental plaque after the use of a self-contaminated multiple use toothbrush and that of a single-use toothbrush.

Settings and Design:

Sixty healthy individuals without any systemic conditions.

Methods and Materials:

The study conducted with 60 participants who were free from any systemic or oral disease and without any adverse habits. In these participants, plaque samples were collected after 1 month use of a self-contaminated multiple use toothbrush. Each participant was given a set of 30 new toothbrushes and a toothpaste tube and instructed to use one toothbrush everyday and discard it after use. The plaque samples were collected on seven days interval and cultured on Mitis Salivarius agar. The colonies were identified and their count was recorded.

Statistical Analysis Used:

Student t test was applied.

Results:

Streptococcus mutans, S. sanguis, S. milleri, and Candida were identified from the samples. A highly marked decrease in their numbers was found after the use of a single-use toothbrush over multiple use toothbrushes.

Conclusions:

As a self-contaminated multiple use toothbrushes can aid microorganisms to grow rapidly into the oral cavity, it may be preferable to change the toothbrush as frequently as possible.

Periodontitis: a host-mediated disruption of microbial homeostasis. Unlearning learned concepts

New concepts evolve when existing ones fail to address known factors adequately or are invalidated by new evidence. For decades periodontitis has been considered to be caused by specific bacteria or groups of bacteria and, accordingly, treatment protocols have largely been based on anti-infective therapies. However, close inspection of current data leads one to question whether these bacteria are the cause or the result of periodontitis. Good evidence is emerging to suggest that it is indeed the host response to oral bacteria that leads to the tissue changes noted in gingivitis. These changes lead to an altered subgingival environment that favors the emergence of 'periodontal pathogens' and the subsequent development of periodontitis if the genetic and external environmental conditions are favorable for disease development. Thus, it seems that it is indeed the initial early host-inflammatory and immune responses occurring during the development of gingivitis, and not specific bacteria or their so-called virulence factors, which determine whether periodontitis develops and progresses. In this review we consider these concepts and their potential to change the way in which we view and manage the inflammatory periodontal diseases.

Persistence of extracrevicular bacterial reservoirs after treatment of aggressive periodontitis

BACKGROUND

The purpose of this study was to test the hypothesis that periodontal pathogens associated with aggressive periodontitis persist in extracrevicular locations following scaling and root planing, systemic antibiotics, and antimicrobial rinses.

METHODS

Eighteen patients with aggressive periodontitis received a clinical examination during which samples of subgingival plaque and buccal epithelial cells were obtained. Treatment consisted of full-mouth root planing, systemic antibiotics, and chlorhexidine rinses. Clinical measurements and sampling were repeated at 3 and 6 months. Quantitative polymerase chain reaction determined the number of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia (previously T. forsythensis), and Treponema denticola in the plaque. Fluorescence in situ hybridization and confocal microscopy determined the extent of intracellular invasion in epithelial cells.

RESULTS

Clinical measurements improved significantly following treatment. All bacterial species except P. gingivalis were significantly reduced in plaque between baseline and 3 months. However, all species showed a trend to repopulate between 3 and 6 months. This increase was statistically significant for log T. denticola counts. All species were detected intracellularly. The percentage of cells infected intracellularly was not affected by therapy.

CONCLUSIONS

The 6-month increasing trend in the levels of plaque bacteria suggests that subgingival recolonization was occurring. Because the presence of these species within epithelial cells was not altered after treatment, it is plausible that recolonization may occur from the oral mucosa. Systemic antibiotics and topical chlorhexidine did not reduce the percentage of invaded epithelial cells. These data support the hypothesis that extracrevicular reservoirs of bacteria exist, which might contribute to recurrent or refractory disease in some patients.

Influence of Sampling Strategy on Microbiologic Results Before and After Periodontal Treatment

BACKGROUND

The aim of this study was to test whether different sampling strategies would influence the microbiologic outcomes by assessing the bacterial load and composition of the subgingival microbiota by means of anaerobic culturing before and after periodontal treatment.

METHODS

The first study (1 versus 4 [1vs4]) included 33 patients with generalized chronic periodontitis. Two sampling strategies were compared, sampling one site from the deepest pocket in the mouth (M1) versus a pooled sample of four sites from the deepest pockets in each quadrant (M4). The second study (2 versus 4 [2vs4]) included 20 patients with generalized chronic periodontitis. The strategy M4 was compared to a pooled sample of two non-adjacent sites in the same quadrant (M2). All samples were processed identically by means of anaerobic culturing. In both studies, a pretreatment sampling was taken. However, in the second study (2vs4), subgingival samples were also taken at 1, 3, and 6 months after periodontal therapy. Quantitative data were compared between strategies by means of t test and signed-rank test; qualitative data were compared by means of 2 x 2 contingency tables.

RESULTS

Pretreatment samples showed that total anaerobic counts were significantly higher for M4 compared to M1 (P <0.001) and M2 (P = 0.025). However, there were no significant differences in regard to percentage of microbiota and counts for each pathogen. Most of the qualitative differences between strategies were caused by false negatives in M1 and M2. Post-treatment samples showed a reduction in total counts and a limited impact in the frequency of detection of periodontal pathogens. M2 detected a significant decrease in the frequency of detection of Porphyromonas gingivalis, which was not confirmed by the M4 strategy.

CONCLUSION

The criteria of selection and the number of sites selected when sampling the subgingival biofilm in patients with generalized chronic periodontitis may influence the detection and quantitation of periodontal pathogens when evaluated by culture especially after treatment.

Contamination of a toothbrush with antibacterial properties by oral microorganisms

OBJECTIVES

The aim of this study was to examine the contamination and the survival rate of periodontopathic and cariogenic species on new toothbrushes with antibacterial properties (coated bristles with triclosan), after a single use in periodontitis patients. The decontamination effect of the use of toothpaste was also evaluated.

METHODS

Ten patients, who consulted the Department of Periodontology, for treatment of chronic periodontitis, were selected. In each patient four different toothbrushes were used. Two quadrants, randomly selected, were each brushed using a different antibacterial toothbrush. In one of these two quadrants toothpaste was used. The same happened with the remaining quadrants, only with regular toothbrushes. After brushing, the toothbrushes were rinsed and stored in room temperature and a dry environment. After 0, 4 and 24h, four tufts, from each toothbrush, were cut and processed for selective and non-selective culturing techniques, followed by identification and quantification of all species found.

RESULTS

Immediately after brushing the toothbrushes harbored a significant number of microorganisms, with no statistically significant difference between the two types of brushes (regular and antibacterial). The reduction of microorganisms from 0 to 4h after brushing was statistically significant (p<0.05). The difference was less obvious from 4 to 24h. When toothpaste was used, brushes harbored significantly (p<0.05) lower numbers of colony-forming units (CFU) compared to those without the use of toothpaste.

CONCLUSIONS

The antibacterial toothbrush with triclosan coated tufts failed to limit the bacterial contamination. The toothpaste, on the other hand, significantly reduced the contamination of toothbrushes.

Dynamics of initial subgingival colonization of ‘pristine’ peri-implant pockets

BACKGROUND

Periodontitis and peri-implantitis are linked to the presence of several key pathogens. The treatment of these infectious processes therefore involves the reduction/eradication of bacteria associated with periodontitis.

METHODS

This prospective, split-mouth, single-blind study followed the colonization of 'pristine' sulci created in 42 partially edentulous patients during implant surgery (e.g. abutment connection). The hypothesis was that the composition of the maturing subgingival plaque in these 'fresh' peri-implant pockets would soon (within 2 weeks) be comparable to the subgingival microbiota of teeth with similar clinical parameters (reference sites), including the presence of bacteria associated with periodontitis. Per patient, four subgingival plaque samples were taken from shallow and medium pockets around implants (test sites), and teeth within the same quadrant (undisturbed microbiota as control sites), 1, 2, 4, 13, 26 and 78 weeks after abutment connection, respectively. The samples were analysed by either checkerboard DNA-DNA hybridization, or cultural techniques, or real-time polymerase chain reaction (PCR) for intra-subject comparisons (teeth vs. implant, for comparable probing depths).

RESULTS

Checkerboard DNA-DNA hybridization and real-time PCR revealed a complex microbiota (including several pathogenic species) in the peri-implant pockets within 2 weeks after abutment connection. After 7 days, the detection frequency for most species (including the bacteria associated with periodontitis) was already nearly identical in samples from the fresh peri-implant pockets (5% and 20% of the microbiota belonging to red and orange complex, respectively) when compared with samples from the reference teeth. Afterwards (e.g. between weeks 2 and 13), the number of bacteria in peri-implant pockets only slightly increased (+/-0.1 log value), with minor changes in the relative proportions of bacteria associated with periodontitis (8% and 33% of the microbiota belonging to red and orange complex, respectively). Although small differences were seen between teeth and implants at week 2 with cultural techniques, a striking similarity in subgingival microbiota was found with this technique from month 3 on, with nearly identical detection frequencies for bacteria associated with periodontitis for both abutment types.

CONCLUSIONS

This study indicates that the initial colonization of peri-implant pockets with bacteria associated with periodontitis occurs within 2 weeks.

Comparison of probes for microbial contamination following use in periodontal pockets of various depths

BACKGROUND

It has been speculated that periodontal probes can transmit periodontal pathogens from site to site. The purpose of this study was to evaluate the potential for bacterial transmission as a function of periodontal probe design.

METHODS

Four different periodontal probes were used to measure probing depths ranging from 0 to 3 mm and > or = 4 mm. Following measurement of each pocket, probes were transported to a laboratory and cultured on blood agar, and colony forming units (CFUs) were determined for total aerobic, anaerobic, and dark-pigmented colonies (DPCs). Eight randomly selected probe tips, representing each probe type and probing depth category, were selected for examination by scanning electron microscopy (SEM) to determine distribution and morphotypes of adhering microbes.

RESULTS

Results showed no statistically significant main effect for probes with respect to CFUs. However, there was a statistically significant increase in CFUs for deeper pockets when compared to pockets 0 to 3 mm. SEM observations were consistent among groups, regardless of probe design or probing depth. All probes exhibited a rough surface texture. Microbes were observed as single organisms or in aggregates and were adherent along the entire length of the probe up to the maximum probing depth.

CONCLUSIONS

There was no difference in CFUs obtained as a function of periodontal probes. The rough surfaces of the probes used in this study likely promoted bacterial adherence through two different mechanisms: through scraping of the pocket walls by the roughened surfaces of the probe and by the high surface-free energy of the metal probes, facilitating bacterial adherence.

Can toothpaste or a toothbrush with antibacterial tufts prevent toothbrush contamination?

BACKGROUND

Periopathogens and cariogenic species survive more than 48 hours on toothbrushes even under dry storage. This study examined a decontamination of toothbrushes by means of the bactericidal effect of different toothpastes or a special coating of the tufts.

METHODS

Eight untreated periodontitis patients were professionally brushed, using a new toothbrush per quadrant and 3 different toothpastes containing either amine/stannous fluoride (AmF/SnF2), amine fluoride (AmF), or a mild surfactant as major antibacterial component (excipient), or no paste (C). The brushes were rinsed and stored dry at room temperature. At different time intervals, 4 tufts per toothbrush were processed for selective and non-selective culturing procedures. The protocol was repeated comparing AmF/SnF2 and C with 2 toothbrushes with coated tufts (coat1 and coat2).

RESULTS

At baseline, C brushes (n = 16) harbored 10(7), 10(8), and 10(6) colony forming units (CFU) of aerobic, anaerobic, and black pigmented species, respectively. After 24 hours 10(6) CFU of aerobic and anaerobic species could still be cultured from 14 of the 16 brushes. Black-pigmented species remained detectable up to 4 hours; detection frequencies for Fusobacterium nucleatum and Streptococcus mutans at 24 hours were 5/16. With AmF/SnF2 and AmF toothpaste the number of adhering bacteria was already 2 log lower at baseline (P<0.05), but not for the excipient (0.5 log, P = 0.7). With AmF/SnF2 no vital species could be detected after 8 hours. AmF reduced the bacterial survival rate significantly more than the excipient, but less than AmF/SnF2 (P<0.05). The bactericidal effect of coat1 and coat2 was negligible when compared to C (P>0.20), and clearly inferior to the AmF/SnF2 paste (P<0.0001). After 24 hours these brushes still harbored >10(5) CFU.

CONCLUSIONS

Toothpastes can significantly reduce contamination of toothbrushes, but their bactericidal activity is dependent on their composition. Coated tufts failed to limit the bacterial contamination.

Guided tissue regeneration using a polylactic acid barrier. Part I: Environmental effects on bacterial colonization

OBJECTIVES

The purpose of this study was to assess the dynamics of bacterial colonization in intra-osseous defects following guided tissue regeneration (GTR) therapy using a resorbable barrier.

PATIENTS AND METHODS

In each of 30 patients, one intra-osseous defect was treated with GTR using a polylactic acid membrane (Guidor). Plaque samples were taken from the defect site, other teeth and mucous membranes following initial therapy (baseline), and at 3, 6 and 12 months after periodontal surgery. Additionally, samples were taken from the defect sites at 1, 2 and 4 weeks. Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), and Bacteroides forsythus (B.f.) were detected by polymerase chain reaction (PCR). Supportive periodontal therapy was performed at 3-month intervals.

RESULTS

In the 29 patients completing the study, the assessed microflora was detected in 3 (A.a.), 13 (P.g.) and 14 (B.f.) defect sites at baseline, in 2 (A.a.), 2 (P.g.) and 2 (B.f.) following surgical debridement, and in 6 (A.a.), 10 (P.g.) and 22 (B.f.) at 12 months. Defect site colonization following GTR therapy was significantly correlated with presurgical colonization at other assessed teeth (A.a. and P.g.: tau = 0.45 and 0.66, respectively; P < 0.001), or on mucous membranes (B.f.: tau = 0.44, P < 0.001).

CONCLUSION

The colonization of periodontal pathogens at sites treated by GTR may correlate with the intra-oral presence of these pathogens before surgery. If colonization of GTR sites by periodontal pathogens is to be prevented, intra-oral suppression/eradication of these pathogens may be required before surgery.

Full-mouth therapy versus individual quadrant root planning: a critical commentary

BACKGROUND

This commentary compares the abilities of full-mouth disinfection (FDIS), full-mouth root planing (FRP), and partial-mouth disinfection (PDIS) to improve periodontal health. FDIS consists of 4 quadrants of root planing completed within 24 hours with adjunctive chlorhexidine therapies (e.g., rinsing, subgingival irrigation, tongue brushing). FRP denotes 4 quadrants of root planing performed within 24 hours, and PDIS refers to root planing individual quadrants of the dentition, spaced 2 weeks apart. A basic premise of administering full-mouth therapy (FDIS or FRP) is to eliminate or reduce bacterial reservoirs within the oral cavity that could inhibit optimal healing of treated sites or cause periodontal disease initiation or progression.

METHODS

Controlled clinical trials that compared the abilities of PDIS and full-mouth root planing with and without adjunctive chlorhexidine chemotherapy to alter periodontal status were reviewed.

RESULTS

Several studies conducted at one treatment center indicated that FDIS and FRP attained greater therapeutic improvements than PDIS with respect to decreasing probing depths (PD), gaining clinical attachment (CAL), diminishing bleeding upon probing, and reducing the subgingival microflora. However, the magnitude of PD reductions and gains of clinical attachment must be carefully interpreted, because initial PD measurements were usually determined after scaling and root planing, which may have caused the results to be overstated. Furthermore, in studies that addressed the utility of FDIS, it was not possible to determine if benefits induced beyond PDIS were due to FRP or administration of multifaceted intraoral chlorhexidine treatments ora combination of both therapies. One investigation that had protocol limitations indicated that similar results were attained by FRP with and without adjunctive chemotherapy. In contrast, recent studies from 2 other treatment centers indicated that there were no significant differences when the efficacy of quadrant-by-quadrant root planing was compared to FRP or FDIS with regard to PD reduction, gains of clinical attachment, and impact on the magnitude and quality of the immune response. POSSIBLE CLINICAL IMPLICATIONS: Conceptually, full-mouth therapy (FRP or FDIS) could reduce the number of patient visits and facilitate more efficient use of treatment time. In addition, there appears to be no major adverse reactions to full-mouth root planing with or without adjunctive chemotherapy. However, small study populations and non-corroborating data from different treatment centers indicate that additional randomized clinical trials are needed to determine if full-mouth therapy provides clinically relevant improvements beyond PDIS.

Probing around implants and teeth with healthy or inflamed peri-implant mucosa/gingiva. A histologic comparison in cynomolgus monkeys (Macaca fascicularis)

The purpose of this study was to obtain a better understanding of probing measurements around osseointegrated oral implants. A comparison was made of probe tip position around Astra Tech implants and teeth of eight cynomolgus monkeys (Macaca fascicularis) in conditions of i) healthy peri-implant mucosa/gingiva, ii) mild mucositis/gingivitis, iii) severe mucositis/gingivitis or iv) peri-implantitis/periodontitis. Histological sections of 128 probes that were attached to implants or teeth with surrounding tissues were prepared by the cutting-grinding technique. No systematic differences were identified in the clinical and histological estimates of the distance between the mucosal/gingival margin and the probe tip. The differences were mainly smaller than 0.5 mm, and in no case were they larger than 0.7 mm. For implants and teeth with healthy peri-implant mucosa/gingiva, the distance between the probe tip and the alveolar bone was similar and ranged from 0.5 to 1.5 mm (P = 0.97). However, the probe tip was closer to bone around implants than around teeth in conditions of mild mucositis/gingivitis (P = 0.034), severe mucositis/gingivitis (P < or = 0.0001) and peri-implantitis/periodontitis (P < or = 0.0001). Around implants with severe mucositis and peri-implantitis, the distance was generally smaller than 0.5 mm, whereas teeth with severe gingivitis and periodontitis showed distances that mainly ranged from 0.5 to 1.5 mm. In conclusion, the probing measurements around osseointegrated oral implants and teeth were different. Even mild marginal inflammation was associated with deeper probe penetration around implants in comparison to teeth.

The intra-oral translocation of periodontopathogens jeopardises the outcome of periodontal therapy

BACKGROUND

Although periodontitis has a multi-factorial aetiology, the success of its therapy mainly focuses on the eradication/reduction of the exogenous/endogenous periodontopathogens. Most of the species colonise several niches within the oral cavity (e.g. the mucosae, the tongue, the saliva, the periodontal pockets and all intra-oral hard surfaces) and even in the oro-pharyngeal area (e.g., the sinus and the tonsils).

METHODS

This review article discusses the intra-oral transmission of periodontopathogens between these niches and analyses clinical studies that support the idea and importance of such an intra-oral translocation.

RESULTS AND CONCLUSIONS

Based on the literature, the oro-pharyngeal area should indeed be considered as a microbiological entity. Because untreated pockets jeopardise the healing of recently instrumented sites, the treatment of periodontitis should involve "a one stage approach" of all pathologic pockets (1-stage full-mouth disinfection) or should at least consider the use of antiseptics during the intervals between consecutive instrumentations, in order to prevent a microbial translocation of periodontopathogens during the healing period. For the same reason, regeneration procedures or the local application of antibiotics should be postponed until a maximal improvement has been obtained in the remaining dentition. This more global approach offers significant additional clinical and microbiological benefits.

Bacterial survival rate on tooth- and interdental brushes in relation to the use of toothpaste

BACKGROUND, AIMS

Previous studies indicated that oral hygiene aids can play a rôle in the intra-oral translocation of pathogens. The survival rate of cariogenic and periodontopathogenic species on toothbrushes, with and without toothpaste, and interdental brushes was presently investigated.

MATERIAL AND METHODS

12 periodontitis patients had their interdental spaces professionally cleaned with interdental brushes and their teeth with new toothbrushes with or without different dentifrices. Each time brushes were rinsed with tap water and stored dry at room temperature. At different time intervals an interdental brush or 4 tufts from a toothbrush were processed for vitality staining and selective and non-selective culturing procedures.

RESULTS

Immediately after rinsing, a toothbrush without toothpaste harboured 10(7), 10(8) and 10(7) colony forming units (CFU) of respectively aerobic, anaerobic and black pigmented species. An insignificant decrease occurred the first 24 hours and after 48 hours still 10(4) CFU of aerobic and anaerobic species could be cultured. No periodontopathogen remained detectable at 8 hours, except for Fusobacterium nucleatum. The proportion of vital bacteria decreased in 48 hours from 50% to 30%. Comparable results were obtained for interdental brushes. The bacterial survival rate on toothbrushes was significantly reduced by the use of a detergent containing toothpaste by 2 log at baseline, another 2 log at 4 hours and an extra log more at 8 hours for aerobic and anaerobic species. A toothpaste without detergent only had an insignificant bactericidal effect.

CONCLUSION

Toothpaste detergents decrease the survival rate of pathogenic species on a toothbrush and can thus limit the risk for bacterial translocation.

The effects of toothpastes on the residual microbial contamination of toothbrushes

BACKGROUND

Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes.

METHODS

Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa.

RESULTS

The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P < .001). The authors compared the isolation frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis.

CONCLUSIONS

Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated.

CLINICAL IMPLICATIONS

Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.

One-stage full-mouth disinfection. Long-term microbiological results analyzed by checkerboard DNA-DNA hybridization

BACKGROUND

Recent studies reported significant, additional clinical and microbiological improvements when severe adult periodontitis was treated via the one-stage full-mouth (OSFM) disinfection approach, instead of a standard treatment scheme with staged instrumentation per quadrant. The OSFM disinfection involves dealing with the remaining oropharyngeal niches such as tonsils, saliva, tongue, and mucosa. The OSFM disinfection procedure involves scaling and root planing of all pockets within 24 hours in combination with chlorhexidine application to all oropharyngeal niches (chairside and at home for 2 months). This study aimed to compare the microbiological shifts with the OSFM approach versus standard therapy.

METHODS

Nineteen patients with advanced chronic periodontitis (AP) and 12 patients with early-onset periodontitis (EOP) were randomly assigned to the test and control groups. The control group (9 AP patients, 6 EOP patients) was scaled and root planed, per quadrant, with 2-week intervals. The test group (10 AP patients and 6 EOP patients) underwent OSFM disinfection treatment. At baseline and after 2, 4, and 8 months, pooled subgingival plaque samples were taken from single- and multi-rooted teeth. The presence and levels of 30 subgingival taxa were determined using whole genomic DNA probes and checkerboard DNA-DNA hybridization.

RESULTS

Both treatments resulted in important reductions of the pathogenic species up to 8 months after therapy, both for their detection level and frequency. The OSFM disinfection resulted in an additional improvement, especially in the AP group. P. gingivalis and B. forsythus were reduced below detection level. The number of beneficial species remained nearly unchanged.

CONCLUSIONS

The OSFM disinfection results in supplementary reductions of periodontal pathogens even after 8 months in the treatment of patients with advanced or early-onset periodontitis.

Clonal infection with Actinobacillus actinomycetemcomitans following periodontal therapy

Mechanical debridement results in a shift of the bacterial composition in the periodontal pocket on the species level. It is unknown, however, whether a clonal change within a species could lead to the emergence of strains with different levels of virulence. Therefore, in the present study, the genetic variability of Actinobacillus actinomycetemcomitans was assessed and strains identified which were associated with periodontal disease progression following periodontal therapy, i.e., refractory periodontitis. Twenty adult patients with untreated periodontitis and subgingival colonization of A. actinomycetemcomitans were randomly assigned to receive full-mouth scaling alone or scaling with an adjunctive antimicrobial therapy. Both groups received supportive periodontal therapy at 3, 6, 9, 12, 18, and 24 months. Subgingival plaque samples were taken at every visit; venous blood was obtained at 24 months only. A. actinomycetemcomitans isolates were typed by the RAPD method, and antibody reactivity against outer membrane proteins was assessed by immunoblot analysis. Eleven distinct RAPD patterns were found in 18 patients completing the study. All patients harbored only one A. actinomycetemcomitans genotype, and within each patient this genotype persisted throughout the 24-month observation period. No differences in the expression of antibody reactivity against outer membrane proteins were found between strains isolated at baseline and at 24 months. Three genotypes were associated with reduced survival rates of teeth without probing attachment loss of 2 mm or more. The results indicated that (i) most patients harbored only one A. actinomycetemcomitans genotype; (ii) the genotype persisted following therapy; and (iii) only some genotypes were associated with refractory periodontitis.

One stage full- versus partial-mouth disinfection in the treatment of chronic adult or generalized early-onset periodontitis. I. Long-term clinical observations

BACKGROUND

A standard treatment strategy for periodontal infections often consists of 4 consecutive sessions of scaling and root planing (per quadrant, at 1- to 2-week intervals), without proper disinfection of the remaining intra-oral niches for periodontopathogens. This could theoretically lead to a reinfection of previously disinfected pockets by bacteria from an untreated region/niche. This study aimed to investigate, over an 8-month period, the clinical benefits of a one stage full-mouth disinfection in the control of severe periodontitis.

METHODS

Sixteen patients with early-onset periodontitis and 24 patients with severe adult periodontitis were randomly assigned to test and control groups. The control group was scaled and root planed, per quadrant, at 2-week intervals and given standard oral hygiene instructions. A one stage full-mouth disinfection (test group) was sought by scaling and root planing the 4 quadrants within 24 hours in combination with the application of chlorhexidine to all intra-oral niches for periodontopathogens. Besides oral hygiene, the test group also rinsed twice daily with a 0.2% chlorhexidine solution and sprayed the tonsils with a 0.2% chlorhexidine spray, for 2 months. The plaque index, gingival index, probing depth, bleeding on probing, gingival recession, and clinical attachment level were recorded at baseline and at 1, 2, 4, and 8 months afterwards.

RESULTS

The one stage full-mouth disinfection resulted, in comparison to the standard therapy, in a significant (P <0.001) additional probing depth reduction and gain in attachment up to 8 months. For initial pockets > or =7 mm, the "additional" probing depth reduction at the 8 month follow-up was 1.2 mm for single-rooted and 0.9 mm for multi-rooted teeth, with corresponding additional gains in attachment of 1.0 mm and 0.8 mm, respectively. The additional improvements were observed for all subgroups (adult periodontitis, generalized early-onset cases, smokers), with the largest differences in the non-smoking adult periodontitis patients.

CONCLUSIONS

These findings suggest that a one stage full-mouth disinfection results in an improved clinical outcome for the treatment of chronic adult or early-onset periodontitis as compared to scaling and root planing per quadrant at 2-week intervals.

Bacteriostatic and bactericidal in vitro activities of clarithromycin and erythromycin against periodontopathic Actinobacillus actinomycetemcomitans

The susceptibilities of 87 periodontitis-associated strains of Actinobacillus actinomycetemcomitans to clarithromycin and erythromycin were determined by standard methodology recommended for Haemophilus influenzae. For clarithromycin the MIC at which 90% of the isolates were inhibited was </=2.0 microg/ml and the minimal bactericidal concentration at which 90% of the strains were killed was </=4.0 microg/ml, suggesting that it would be a candidate for therapeutic trials in patients with periodontitis.

The description of a unique population with a very high prevalence of localized juvenile periodontitis

The reported prevalence of localized juvenile periodontitis (LJP) amongst teenagers and young adults varies greatly. The etiology of LJP has been related to Actinobacillus actinomycetemcomitans (Aa), and it has also been suggested that there may be a transmission of Aa within families resulting in the familial distribution of the disease. This study describes the high prevalence of LJP in adolescents, 12-20 years of age, from a group of nuclear families living and functioning in a closed, closely knit community. The survey was carried out on a population of teenagers that had attended the same school and their siblings. All students attending that school and their siblings were examined. They were given a periodontal examination and a questionnaire relating to their demographic details and their personal oral hygiene habits. The periodontal examination was limited to the incisors and first molar teeth. Plaque index (PlI), gingival index (GI), the presence or absence of bleeding on probing (BOP), probing pocket depth (PPD) and recession were measured. All patients having at least two of the examined sites with probing pocket depth > or =5 mm or one site > or =6 mm were considered as possible sufferers from LJP and had a full mouth periapical radiographic survey carried out using a paralleling technique to confirm the diagnosis. At the sites with probing pocket depth > or =5 mm, a Shei ruler was used to measure the % of the root coronal to the alveolar bone. A cut off point of > or =20% was used as a measure of true bone loss confirming the clinical diagnosis of LJP. 86 individuals from 30 families comprised the population of interest. There were 44 males and 42 females with a mean age of 14.7+/-2.3. Of the 86 individuals examined, 33 individuals from 15 families were diagnosed as having LJP (38.4%). None of the individuals examined showed any evidence of the generalized form of juvenile periodontitis. The mean age of the LJP patients was 15+/-2.3 yrs. with a 1:1.75 male to female ratio. Except for 2 pairs of families with genetic ties, no familial connections could be traced between the different nuclear families affected by LJP despite repeated and intensive questioning. There were no significant differences in the PlI and the GI between the groups while the LJP group had significantly higher BOP, PPD and PAL than the non-LJP group. These finding strongly suggest an environmental influence in the etiology of the disease.

The distribution and transmission of Actinobacillus actinomycetemcomitans in families with localized juvenile periodontitis

The prevalence and distribution of A. actinomycetemcomitans in families where at least one family member (proband) suffered from localized juvenile periodontitis was investigated. 25 probands with localized juvenile periodontitis (LJP) and their 78 close family members were screened for the presence of A. actinomycetemcomitans. Among these 25 families, 10 contained at least one additional family member colonized with oral A. actinomycetemcomitans. Genomic DNA from subgingival A. actinomycetemcomitans strains from each of the probands and their family members were amplified and characterized by the polymerase chain reaction (PCR) using a single primer known to distinguish A. actinomycetemcomitans strains. The PCR products from each strain were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV light transillumination. The studies showed that 41.2% of the parents and 58% of the siblings in this LJP-based population harbored the bacterium. Comparison of the PCR generated amplitypes showed that there was a wide distribution of amplitypes among the probands and immediate relatives. No clear transmission paths were observed in this specific population.

The effect of a one-stage full-mouth disinfection on different intra-oral niches. Clinical and microbiological observations

A treatment for periodontal infections often consists of consecutive rootplanings (per quadrant, at a 1- to 2-week interval), without a proper disinfection of the remaining intra-oral niches (untreated pockets, tongue, saliva, mucosa and tonsils). Such an approach, could theoretically lead to a reinfection of previously-treated pockets. The present study aims to examine the effect of a full-mouth disinfection on the microbiota in the above-mentioned niches. Moreover, the clinical benefit of such an approach was investigated. 16 patients with severe periodontitis were randomly allocated to a test and a control group. The patients from the control group were scaled and rootplaned, per quadrant, at 2-week intervals and obtained oral hygiene instructions. The patients from the test group received a full-mouth disinfection consisting of: scaling and rootplaning of all pockets in 2 visits within 24 h, in combination with tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with a 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. Besides oral hygiene, the test group rinsed 2x daily with 0.2% chlorhexidine and sprayed the tonsils with a 0.2% chlorhexidine for 2 months. Plaque samples (pockets, tongue, mucosa and saliva) were taken at baseline and after 2 and 4 months, and changes in probing depth, attachment level and bleeding on probing were reported. The full-mouth disinfection resulted in a statistically significant additional reduction/elimination of periodontopathogens, especially in the subgingival pockets, but also in the other niches. These microbiological improvements were reflected in a statistically-significant higher probing depth reduction and attachment gain in the test patients. These findings suggest that a disinfection of all intra-oral niches within a short time span leads to significant clinical and microbiological improvements for up to 4 months.

In vitro antimicrobial susceptibility of periodontopathic Actinobacillus actinomycetemcomitans to roxithromycin and erythromycin

The in vitro minimal inhibitory concentrations (MIC) and minimal bactericidal concentration (MBC) of roxithromycin and erythromycin against Actinobacillus actinomycetemcomitans were evaluated. Sixty-seven different A. actinomycetemcomitans isolated from periodontal pockets of 101 subjects with different forms of early-onset and adult periodontitis and three reference strains of A. actinomycetemcomitans (ATCC 29522, ATCC 29523, and NCTC 9710) were included in this study. Erythromycin showed poor in vitro activity against A. actinomycetemcomitans; roxithromycin, on the contrary, exhibited good in vitro activity. Moreover, roxithromycin showed the best in vitro antimicrobial activity against 17 serotype a and 12 serotype c subpopulations of A. actinomycetemcomitans; against 38 serotype b subpopulation of A. actinomycetemcomitans, roxithromycin was consistently active. Roxithromycin exhibited MBC values usually equal to, or one-fold higher than MIC values. All the MBC values of erythromycin were three- to four-fold higher than the respective MIC result. Since roxithromycin is characterized by high concentrations in serum and good penetration and diffusion into gingival tissue, it could be expected to pass into the gingival crevicular fluid at levels sufficiently high to inhibit A. actinomycetemcomitans in vivo. These data indicate that roxithromycin might be a potential candidate for therapeutic trials in patients with A. actinomycetemcomitans-associated periodontitis.

Experimental gingivitis in periodontitis-susceptible subjects

The purpose of this study was to evaluate clinical, microbiological, and gingival crevicular fluid (GCF) profiles in periodontitis-resistant and periodontitis-susceptible subjects during 4 weeks of experimental gingivitis. Experimental groups of similar ages were defined as gingivitis controls (GC; n = 10) and history of rapidly progressive periodontitis (RPP; n = 10), respectively. Prior to baseline, all subjects achieved good plaque control (plaque index (P1I) approximately 0) and gingival health (gingival index (GI) = 0), and had probing depths < or = 4 mm on experimental teeth. For 4 weeks after baseline, oral hygiene around maxillary 2nd premolar and 1st molar teeth was inhibited by a plaque guard. The plaque guard was removed weekly for GCF sampling to determine interleukin (IL)-1 beta and prostaglandin (PG)E2 amounts by ELISAs. In addition, P1I, GI, probing depth, and gingival recession measurements were made. Subgingival plaque darkfield microscopy and DNA probe analysis also were performed. Results indicated that clinical signs of inflammation, microbiological patterns and GCF profiles progressed similarly in both groups. However, plaque accumulated more rapidly in the susceptible subjects. P1I in RPP at 4 weeks was 2.1 +/- 0.1 compared to 1.5 +/- 0.2 in GC, with an incidence of P1I > of 100% versus 50%, respectively (logistic regression; p < 0.0001). Hence, the clinical, microbiological and host factors selected for this study were unrelated to previous susceptibility to periodontitis when evaluated in the experimental gingivitis model. However, the increased rate of plaque accumulation, following thorough plaque removal, in RPP patients suggests a potential factor in disease recurrence in these susceptible subjects.

Bacterial transmission in periodontal diseases: a critical review

This review paper addresses intra- and extra-familial transfer of bacteria associated with periodontal diseases. Recent advances in molecular biology provide sensitive methods to differentiate organisms within the same species, thereby facilitating tracking routes of their transmission. Evidence for the passing of microorganisms between parents and children is particularly strong. In this regard, molecular genetic techniques have demonstrated that if a child is colonized by a potentially pathogenic species, then one of the parents will usually harbor genotypically identical bacteria. The data also indicate that transfer of bacteria between spouses occur, but it appears to happen infrequently. Saliva appears to be a major vector for bacterial transmission. However, the transfer of organisms does not necessarily result in colonization or infection of the host. Furthermore, individuals who harbor putative pathogens frequently do not manifest any signs of periodontal disease. This is attributed to host defenses, bacterial antagonism, and possibly lack of pathogenicity of infecting organisms. It is concluded, based upon current evidence, that periodontal pathogens are communicable; however, they are not readily transmissible.

One-stage Full-mouth Disinfection to Overcome Intra-oral Transmission of Periodontopathogens

The oral cavity offers a range of different niches where periodontopathogens can adhere and survive (e.g. the mucosa, the tongue, the tonsils, the saliva and all intra-oral hard surfaces such as teeth, dentures, oral implants). Transmission of bacteria from one niche to another is likely to occur. Recent studies, for example, illustrated that initially sterile abutments of oral implants were rapidly colonized by bacteria from the subgingival environment around teeth. This transmission of bacteria can occur spontaneously via the saliva, or by means of oral hygiene aids and/or dental instruments. Such an intra-oral transmission, if it occurs at a high speed, could jeopardize the outcome of periodontal therapy. To overcome a bacterial transmission, a 'one-stage full-mouth disinfection' was recently introduced for the treatment of periodontal infections. This new treatment strategy resulted in significant clinical and microbiological improvements when compared with the standard sequential treatment.

Full- versus partial-mouth disinfection in the treatment of periodontal infections. Long-term clinical observations of a pilot study

A classical treatment for chronic adult periodontitis consists of four to six consecutive sessions of scaling and root planing at a 1- to 2-week interval. Such a so-called "quadrant or sextant therapy" might result in a reinfection of a previously disinfected area by bacteria from an untreated region. The purpose of this study was to investigate, over an 8-month period, the clinical benefits of full-mouth disinfection within a 24-hour period in the control of chronic periodontitis. Ten adult patients with advanced chronic periodontitis were randomly assigned to a test and a control group. The control group received the standard scheme of initial periodontal therapy, consisting of scaling and root planing of the four quadrants was performed within 24 hours and immediately followed by a thorough supra- and subgingival chlorhexidine application to limit any transfer of bacteria. The latter involved tongue brushing with a 1% chlorhexidine gel for 60 seconds, mouthrinsing with a 0.2% chlorhexidine solution twice for 60 seconds, repeated subgingival irrigation of all pockets with a 1% chlorhexidine gel (3 times within 10 minutes), and mouthrinsing twice daily with a 0.2% chlorhexidine solution during 2 weeks. In addition, both groups received thorough oral hygiene instructions. The plaque index, gingival index, probing depth, gingival recession, and bleeding on probing were recorded prior to professional cleaning and at 1, 2, 4, and 8 months afterwards. Although the test group scored higher plaque indices than the control group, especially at months 2 and 4, the gingival index and bleeding tendency showed similar improvements with time. However, when the gingival/plaque ratio was considered, the latter was lower in the test group at all follow-up visits. For pockets > or = 7 mm, full-mouth disinfection showed a significantly (P = 0.01) higher reduction in probing depth at each follow-up visit with, at month 8, a reduction of 4 mm (from 8 mm to 4 mm), in comparison to 3 mm (from 8 mm to 5 mm) for the classical therapy. The increase in gingival recession in the full-mouth disinfection group remained below 0.7 mm, while in the control group it reached 1.9 mm after 8 months. This resulted in a gain of clinical attachment level of 3.7 mm for the test group versus 1.9 mm for the control group. A radiographical examination also indicated a superior improvement for the test group when compared to the control group. This pilot study suggests that a full-mouth disinfection in one day results in an improved clinical outcome in chronic periodontitis as compared to scalings per quadrant at 2-week intervals over several weeks.

The adherence of periodontopathogens to periodontal probes. A possible factor in intra-oral transmission?

Periodontal probes have previously been shown to harbor several bacterial types or species after probing periodontally diseased pockets. This study aims to identify and quantify periodontopathogens that may adhere to a periodontal probe by culturing techniques. It also examines the probe's roughness on its capability to collect bacteria, comparing Merrit-B probes (with deep indentations) with TPS probes (with smooth surfaces). From the differential phase contrast microscopy findings it was seen that, while paper-points harbored nearly 50% motile rods or spirochetes, the periodontal probes were just at, or below, the 20% threshold level for pathogenicity (23.6% for the Merrit-B probe and 11.3% for the TPS probe). The cultural data showed that paper-points had significantly higher (P < 0.05) numbers of anaerobic bacteria than the 2 probe types, which still harbored up to 10(7) CFU. No significant differences could be detected between the probes. When specific periodontopathic species were considered, it was seen that for all species, even for Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis, the detection frequency was comparable for the 3 sampling devices. However, the levels of Prevotella intermedia and Campylobacter rectus was significantly higher in samples from paper-points (P < 0.05), but still their numbers reached even 10(5) on the probes. Differences among the 2 probe types were again negligible. Periodontal probes harbor relatively high numbers of bacteria found in periodontal pockets and may be able to carry them over to other sites. Further studies are needed to determine if, and to what extent, transmission occurs during periodontal probing.

Intraoral transmission and the colonization of oral hard surfaces

The sterile abutments of 2-stage implants offer a unique model to study intraoral transmission and bacterial colonization patterns in the oral cavity. This study aimed to examine, by means of differential phase contrast microscopy, parameters that influence the intra-oral colonization of these abutments. In part one, 159 partially edentulous patients were examined to determine the influence on the microbial composition around implants of the following parameters: 1) the relative location of the teeth in relation to the implants; 2) the microbial composition of the subgingival plaque around these teeth; and 3) the frequency of deep pockets around the natural dentition. The results indicate that the subgingival flora around the implants harbored more spirochetes and motile rods when teeth were present in the same jaw (P < 0.05) and/or when the pockets around them harbored a pathogenic flora (P < 0.05). In part two, the impact of periodontitis around the remaining teeth and of probing depth around the implants on the composition of the peri-implant subgingival flora was investigated. Thirty-one partially edentulous implant patients were classified according to their periodontal condition into 3 groups: healthy (n = 17), chronic periodontitis (n = 11), and refractory periodontitis (n = 3). The samples from deep pockets (> or = 4 mm) around implants showed significant increases in the total proportion of spirochetes and motile organisms when compared to samples from healthy subjects (1.2%) or in chronic periodontitis patients (21.0%), or to patients suffering from refractory periodontitis (31.5%). For shallow pockets (< 4 mm) significant differences were only detected between subjects with a healthy periodontium (1.0%) or chronic periodontitis (2.4%), and refractory periodontitis cases (19.7%). The present findings confirm the transmission of microorganisms from teeth to implants, and thereby highlight the importance of periodontal health around the natural dentition before as well as after implant installation.

Full- versus partial-mouth disinfection in the treatment of periodontal infections. A pilot study: long-term microbiological observations

A standard periodontal treatment consists of 4 to 6 scalings and rootplanings at a 1- to 2-week interval, which allows reinfection of a previously disinfected area before completion of the treatment. The present pilot study aims to examine the microbiological long-term effects of a full-mouth disinfection. 10 patients with advanced chronic periodontitis were randomly allocated to a test and control group. The patients from the control group received scaling and rootplaning and oral hygiene instructions at a 2-week interval. The full-mouth disinfection (test group) consisted of a full-mouth scaling and rootplaning in 2 visits within 24 h in combination with: tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. The patients of the test group were instructed to rinse 2x daily with 0.2% chlorhexidine. Plaque samples were taken at baseline and after 1, 2, 4 and 8 months. Differential phase-contrast microscopy showed a significantly larger reduction of spirochetes and motile organisms in the test group up to month 2 for the single-rooted and up to month 8 for the multi-rooted teeth. Furthermore, the culture data supported the effectiveness of the new treatment strategy. In both groups, the number of anaerobic CFU decreased 1 log around single- and 0.5 log around multi-rooted teeth. The number of anaerobic CFU remained low in the test group, in contrast to the control group. At 1 month, the test group harboured a significantly (p<0.01) lower proportion of pathogenic organisms, but this difference disappeared with time. Moreover, the test sites showed a significantly higher (p<0.02) increase in the proportion of beneficial micro-organisms up to 4 months. These findings suggest that a full-mouth disinfection leads to a significant microbiological improvement up to 2 months, which could be consolidated, although not significant, for the next 6 months.

Source of suspected periodontal pathogens re-emerging after periodontal treatment

To clarify the source of re-emerging periodontal pathogens after treatment, we compared the ribotypes of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens group and Campylobacter rectus before and after treatment in 7 periodontitis patients and in 6 of the spouses. The patients harbored A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group or C. rectus in their subgingival or salivary samples before treatment. The respective bacterial species were not detected 1 month after treatment, but reappeared by 6 months later. When available, 4 random colonies of each of the 4 species were isolated from both subgingival and salivary samples at each sampling occasion, the isolates were subcultured, identified and typed applying pheno- and genotypic intraspecies characterization methods. Altogether 90 strains of A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group and C. rectus were available from 2, 3, 2 and 4 patients, respectively. The pre- and post-treatment ribotypes of A. actinomycetemcomitans-, P. gingivalis- and P. intermedia/P. nigrescens group-isolates were identical in all respective patients. The pre- and post-treatment ribotypes of C. rectus were identical in 1 of 4 patients, whereas 2 patients harbored a previously not detected post-treatment ribotype and 1 patient harbored the initial and a previously not detected post-treatment ribotype. To study the possibility that periodontitis patients may acquire strains from the spouse after treatment, isolates of A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group and C. rectus (n = 95) from the patients' spouses were ribotyped and compared with those of the patients. The patient exhibited his own post-treatment ribotypes, different from those of the spouse, of A. actinomycetemcomitans and P. gingivalis in 1 couple and of P. intermedia/P. nigrescens group and C. rectus in 1 couple. In the 2 patients who harbored a previously not detected post-treatment ribotype of C. rectus, one patient shared the new ribotype with the spouse, whereas the other one did not. Although an exogenous source cannot be fully ruled out, the patient's own oral flora seems to be the main source of re-emerging periodontal pathogens after treatment.

Personal risk factors for generalized periodontitis

Periodontitis is generally considered to be a consequence of an unfavourable host-parasite interaction in which bacteria are the determinants of disease. An intense search continues for the bacteria, specific or non-specific, that are responsible for periodontitis and various forms of the periodontal diseases have been associated with, and are widely believed to be caused by, specific bacterial groups. However, the distribution of periodontopathic bacteria is far wider than the distribution of periodontitis, indicating that the association between bacteria and periodontitis is weak. This paper proposes a paradigm for the etiology of generalized periodontitis in which 'host' factors are not only those triggered by bacteria (the agent) but are also those personal factors that influence the outcome of the host/parasite relationship. The personal factors that diminish the efficiency of host defense may include psycho-social stress from the social environment, factors from the lifestyle such as diet, smoking and alcoholism and systemic factors such as intercurrent disease or deficiencies within the immune/inflammatory system. A model is described in which the interaction of personal factors with the social environment provides the potential for the initiation of periodontitis. Biological variation is significant and the combination of factors that cause generalized periodontitis or any other chronic disease in one individual may not result in dental or any other chronic disease in another.

Evaluation of antimicrobial mouthrinses and their bactericidal effectiveness

The mechanisms of action of antimicrobials have been based in the past on in vitro data obtained from laboratory experiments performed on pure cultures of bacteria. A more complete understanding of oral antimicrobials and their mechanisms of action will results from testing of agents in systems that more closely resemble environmental areas existing in the oral cavity. It is proposed that mechanisms of drug action be studied with a drug held at suboptimal (sublethal) concentrations for short periods and in a dynamic environment that resembles the mouth. Adequate guidelines provided by the American Dental Association Council on Dental Therapeutics are available and have helped to determine the efficacy of these agents over long periods in appropriate populations.

The distribution and transmission of Actinobacillus actinomycetemcomitans in families with established adult periodontitis

The prevalence and genotype distribution of Actinobacillus actinomycetemcomitans strains in families where at least one adult family member (proband) suffered from periodontal disease was investigated to better understand how this periodontal organism is acquired or transmitted. Fifteen probands with severe (established) periodontal disease (EPD) and their 46 immediate family members were sampled for A. actinomycetemcomitans. Among the 15 families, 10 contained at least one additional family member colonized with oral A. actinomycetemcomitans. Genomic DNA from 3 subgingival A. actinomycetemcomitans strains from each of the 10 probands and their 17 family members were amplified and characterized by the polymerase chain reaction (PCR) using a single arbitrary primer known to distinguish A. actinomycetemcomitans strains. The PCR products from each strain were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV light transillumination. The amplification products migrated to form readily distinguishable bands and, since the banding patterns were characteristic of strains of A. actinomycetemcomitans, these patterns were called "amplitypes." The culture studies showed that 51% of all patients suffering from EPD carried oral A. actinomycetemcomitans. Moreover, 50% of their spouses and 30% of their children harbored the bacterium. Comparison of the PCR-generated amplitypes showed that 26 out of 27 individuals had strains exhibiting a single amplitype of A. actinomycetemcomitans, the 27th being colonized by 2 different amplitypes. They also showed that in 6 out of 7 families, the husband and wife did not harbor the same A. actinomycetemcomitans amplitype. Furthermore, most often children carried an an amplitype identical to one of the parents.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulpal disease and bursts of periodontal attachment loss

Progression of periodontitis is currently thought to occur during bursts of activity, followed by periods of remission, when healing may occur. This concept contrasts with the older hypothesis that periodontitis was continuously, but slowly, progressive throughout life. At present, there is no proof of the conventional (microbiological) hypothesis which gives a major role to site-specific bacteria in the initiation of bursts of attachment loss. An alternative hypothesis is presented in this paper which accounts for periodontal attachment loss by pathways that are independent of plaque. Severe lesions of the periodontium caused by pulpal pathoses (apical and retrograde periodontitis) are known to form at any level of the periodontium, not only at the root apex. When these lesions cause destruction of the periodontal tissues at the alveolar crest, and when plaque, calculus and gingivitis are also present, an endodontic origin is rarely suspected. Three pathways are proposed to account for the development of localized periodontal attachment loss consequent to pulpal disease. This hypothesis accounts for the sudden deterioration of periodontal sites under regular review, the strict localization of alveolar defects with normal alveolar bone immediately adjacent, the presence of site-specific bacteria (secondary colonizers of deep pockets) which cannot cause disease when transferred to healthy sites, and the antibody responses directed against them.

Suppression of subgingival Actinobacillus actinomycetemcomitans in localized juvenile periodontitis by systemic tetracycline

The current study assessed the clinical and microbiological effects of systemic antimicrobial therapy alone in Actinobacillus actinomycetemcomitans-infected adolescents with periodontal disease. The study involved 6 localized juvenile periodontitis patients 13-18 years of age, who harbored high numbers of A. actinomycetemcomitans in subgingival plaque samples. The periodontal lesions were microbiologically monitored by selective culture, and clinically assessed for probing pocket depth and periodontal attachment level 3 months prior to baseline, and at 3, 6, 12, and 24 months posttreatment. Tetracycline-HCl (250 mg/QID) was prescribed until 1 week after subgingival A. actinomycetemcomitans was no longer detectable or for a maximum of 8 weeks. During 3 months prior to treatment, pocket depth was unchanged, and was then significantly reduced from an average of 7.1 mm to 5.1 mm 12 months after treatment (p = 0.02). The mean change in clinical attachment level was a gain of 1.4 mm between baseline and 12 months (p = 0.02). 3 of the 6 patients were still infected with A. actinomycetemcomitans after 8 weeks of antibiotic therapy and 4 subjects were infected at 12 months. Numbers of A. actinomycetemcomitans were still suppressed in most lesions. There was a strong association between mean numbers of A. actinomycetemcomitans in periodontal pockets and mean change in probing attachment level at any given time point. For 22 available comparisons, derived from all time points, there was a strong association (r = 0.68) between subgingival A. actinomycetemcomitans and change in probing attachment level.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of transmission of resistant bacteria between periodontal sites during subgingival application of antibiotics

This study was designed to investigate whether antibiotic resistant micro-organisms are able to contaminate and survive on syringe tips used for subgingival deposition of antibiotics, and to test simple and effective means of disinfecting the syringe tip between applications. In the first part of the study, syringe tips used for application of Minocycline subgingival formula in 20 adult periodontitis patients were cultured for bacteria resistant to this drug before and after disinfecting them with ethanol. The results showed that 80% of the unwashed syringes were culture positive for minocycline resistant bacteria, whereas only 1 ethanol washed syringe tip was contaminated. In part II of the study, after dispensing minocycline periodontal formula in 20 patients, 10 of the syringe tips were washed with ethanol while 10 were left untreated. All syringes were stored in a refrigerator for 8 days, whereafter the tips were sampled for resistant bacteria. 20% of the unwashed tips were contaminated after 8 days incubation at 4 degrees C. None of the ethanol washed syringe tips were culture positive. We conclude that syringe tips may be contaminated with antibiotic resistant bacteria after dispensing the antibiotic in periodontal pockets. The transmission of these bacteria to other periodontal sites may be avoided by disinfecting the syringe tip with ethanol between applications. We have also shown that antibiotic resistant bacteria may survive on the syringe tip following 8 days storage in a refrigerator, suggesting that syringes used for subgingival deposition of an antibiotic should not be stored for reuse.

Topical application of tetracycline-HCl in human periodontitis

Previous in vitro studies have suggested that tetracycline-HCl (TTC-HCl) is adsorbed and actively released from root dentin. The aim of the current study was to evaluate the binding to and release of TTC-HCl from human root dentin surfaces in vivo, and to evaluate the clinical utility of TTC-HCl irrigation as an adjunct to scaling and root planing. Experiment I utilized two contralateral mandibular single-rooted teeth which were examined in four adults with severe generalized periodontitis. One tooth in each patient was carefully scaled and root planed, under local anesthesia, and the other used as an unscaled control. Each subgingival root surface was irrigated for 5 min with an aqueous TTC-HCl solution at a concentration of 100 mg/ml. Gingival crevicular fluid samples were collected on paper strips for the next three weeks. The TTC-HCl concentrations in each sample were determined by the inhibition zone of B. cereus cultured on agar plates. The TTC-HCl concentrations in gingival crevicular fluid collected 15 min after irrigation were 3100 +/- 670 micrograms/ml from the scaled lesions and 4700 +/- 1300 micrograms/ml from the unscaled root surfaces. The antibiotic concentrations decreased logarithmically over the next 7 days; 1500 +/- 270 micrograms/ml and 1100 +/- 330 micrograms/ml at 2 h, 880 +/- 350 micrograms/ml and 1300 +/- 360 micrograms/ml at 6 h and 19 +/- 5 micrograms/ml and 31 +/- 26 micrograms/ml at 1 week for scaled and unscaled root surfaces, respectively. Results for week two and three indicated an average of over 8 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Early onset periodontitis in the United States of America

A National Survey of the Oral Health of U.S. children aged 5 to 17 was conducted by the National Institute of Dental Research during the 1986-87 school year. Eleven thousand and seven adolescents aged 14 to 17 years received a periodontal assessment. Their patterns of loss of periodontal attachment as assessed by probing at mesial sites were used to classify adolescents as cases of early onset periodontitis. Approximately 0.53% of adolescents nation-wide were estimated to have localized juvenile periodontitis (LJP), 0.13% to have generalized juvenile periodontitis (GJP), and 1.61% to have incidental loss of attachment (LA) (greater than or equal to 3 mm on 1 or more teeth). The total number of adolescents affected were not trivial. Close to 70,000 adolescents in the U.S. were estimated to have LJP in 1986-87. More destructive GJP affected an estimated 17,000 adolescents. Another 212,000 adolescents were estimated to have incidental LA. Blacks were at much greater risk for all forms of early onset periodontitis than whites. Males were clearly more likely (4.3 to 1) to have GJP than females when other variables were statistically controlled. Gender associations were more complicated for LJP because gender interacted with race. Black males were 2.9 times as likely to have LJP as black females. In contrast, white females were more likely than white males to have the disease by about the same odds. When interactions among demographic variables exist, caution must be taken in comparing results from different studies.

Dental bacterial plaques. Nature and role in periodontal disease

Antony van Leeuwenhoek first described oral bacteria. However, not until almost 200 years later was the famous Koch postulate introduced. Since then, research has extensively been performed regarding the development and microbiology of dental plaques. In spite of the complexity of the developing flora of supragingival plaque, culture studies have shown a remarkably orderly succession of organisms. Lately, the concept of microbial specificity in the etiology of periodontal diseases has been widely suggested, i.e., that different forms of periodontal disease are associated with qualitatively distinct dental plaques. Cross-sectional and longitudinal studies of the predominant cultivable microflora reveal that only a small number of the over 300 species found in human subgingival plaques are associated with periodontal disease. Among the commonly mentioned are: Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, Bacteroides intermedius, Capnocytophaga sp., Eikenella corrodens, Fusobacterium nucleatum, and Wolinella recta, as well as certain gram-positive bacteria such as Eubacterium species. Anti-infective therapy for many systemic infections equals the use of antimicrobial drugs. However, for localized infections like periodontal diseases, treatment may consist of a combination of mechanical wound debridement and the application of an antimicrobial agent. The general effectiveness of mechanical anti-infective therapy and successful oral hygiene in the management of periodontal disease is well established in the literature and has met the test of success in clinical practice for most cases of periodontitis in adults. The definition of periodontal pathogens as either opportunistic pathogens, or as exogenous pathogens carries with it significant implications.(ABSTRACT TRUNCATED AT 250 WORDS)