Effects of treatment on antibody titer to Porphyromonas gingivalis in gingival crevicular fluid of patients with rapidly progressive periodontitis

Variations in IgG antibody subclass responses to oral bacteria: Effects of periodontal disease and modifying factors

BACKGROUND AND OBJECTIVE

Local and systemic IgG antibodies or oral bacteria have been described with periodontitis. We extended these observations by assessing the impact of a range of intrinsic factors on serum IgG subclass antibodies to both commensal and pathogenic oral bacteria that would contribute to variations in immune protection or disease susceptibility in periodontitis have not been described.

METHODS

Subjects (n = 278) were classified as healthy, gingivitis, or periodontitis and categorized as mild, moderate, and severe periodontitis. Demographic stratification included sex, age, race/ethnicity, smoking, and obesity. Whole formalin-fixed bacteria were used as antigens to detect serum immunoglobulin (Ig)G subclass antibody levels using an ELISA.

RESULTS

The greatest differences in variations in IgG subclasses occurred in periodontitis versus health or gingivitis to bacteria considered oral pathogens (eg, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola) with IgG1, IgG2, and IgG4 increased by three- to sevenfold with Pg. Differences in subclass levels and distribution were also observed related to disease severity, particularly related to individual subclass responses to Pg. Examination of the overall population showed that females had elevated antibody, reflected by elevated IgG2 amounts/proportions. The older group of subjects demonstrated elevated antibody to multiple oral bacteria, lacking any particular subclass pattern. IgG2 antibody to Aa and Pg was increased in smokers. Multiple IgG subclass antibody levels to oral pathogens were significantly decreased in the obese subset within this population.

CONCLUSION

This investigation identified patterns of IgG subclass antibody responses to oral bacteria and demonstrated substantial effects of disease impacting the level and subclass distribution of antibody to an array of oral bacteria. Altered subclass antibody profiles most often in IgG2 levels and for antibody to P. gingivalis were found related to sex, age, disease severity, race/ethnicity, smoking, and obesity to both pathogens and commensal bacteria.

Heterogeneity of human serum antibody responses to P. gingivalis in periodontitis: Effects of age, race/ethnicity, and sex

Aging humans display an increased prevalence and severity of periodontitis, although the mechanisms underlying these findings remain poorly understood. This report examined antigenic diversity of P. gingivalis related to disease presence and patient demographics. Serum IgG antibody to P. gingivalis strains ATCC33277, FDC381, W50 (ATCC53978), W83, A7A1-28 (ATCC53977) and A7436 was measured in 426 participants [periodontally healthy (n = 61), gingivitis (N = 66) or various levels of periodontitis (N = 299)]. We hypothesized that antigenic diversity in P. gingivalis could contribute to a lack of "immunity" in the chronic infections of periodontal disease. Across the strains, the antibody levels in the oldest age group were lower than in the youngest groups, and severe periodontitis patients did not show higher antibody with aging. While 80 % of the periodontitis patients in any age group showed an elevated response to at least one of the P. gingivalis strains, the patterns of individual responses in the older group were also substantially different than the other age groups. Significantly greater numbers of older patients showed strain-specific antibody profiles to only 1 strain. The findings support that P. gingivalis may demonstrate antigenic diversity/drift within patients and could be one factor to help explain the inefficiency/ineffectiveness of the adaptive immune response in managing the infection.

PerioVax3, a key antigenic determinant with immunoprotective potential against periodontal pathogen

Treponema (T.) denticola is one of the key etiological agents in the development of periodontitis. The major outer sheath protein (Msp) of T. denticola has been shown to mediate pathogenesis and to facilitate adhesion of T. denticola to mucosal surfaces. This study aimed to find short polypeptides in the amino acid sequence of Msp which may be immunogenic and might elicit protective antisera against T. denticola. The complete msp sequence was divided into six fragments and the corresponding genes were cloned and expressed. Antisera against the polypeptides were raised in rabbits and fragment 3 (F3), hereinafter called PerioVax3 was the most potent fragment of the Msp in terms of yielding high titer antiserum. An adhesion assay was done to examine the inhibitory effects of antisera on the attachment of T. denticola to human gingival fibroblasts (HGFs) and human fibronectin. Antiserum against PerioVax3 significantly inhibited attachment of T. denticola to the substratum. Also, antiserum against PerioVax3 inhibited detachment of HGFs upon T. denticola exposure. To begin examining the clinical relevance of this work, blood samples from 12 sever periodontitis patients were collected and the sera were used in western blotting against the recombinant polypeptides. Periodontitis patient antisera exclusively detected PerioVax3 in western blotting. The data suggest that PerioVax3 carries epitopes that may trigger humoral immunity against T. denticola, which may protect against its adhesion functions. The complexity of periodontitis suggests that PerioVax3 may be considered for testing as a component of an experimental multivalent periodontal vaccine in further preclinical and clinical studies.

Age and Periodontal Health - Immunological View

PURPOSE OF THE REVIEW

Aging clearly impacts a wide array of systems, in particular the breadth of the immune system leading to immunosenescence, altered immunoactivation, and coincident inflammaging processes. The net result of these changes leads to increased susceptibility to infections, increased neoplastic occurrences, and elevated frequency of autoimmune diseases with aging. However, as the bacteria in the oral microbiome that contribute to the chronic infection of periodontitis is acquired earlier in life, the characteristics of the innate and adaptive immune systems to regulate these members of the autochthonous microbiota across the lifespan remains ill defined.

RECENT FINDINGS

Clear data demonstrate that both cells and molecules of the innate and adaptive immune response are adversely impacted by aging, including in the oral cavity, yielding a reasonable tenet that the increased periodontitis noted in aging populations is reflective of the age-associated immune dysregulation. Additionally, this facet of host-microbe interactions and disease needs to accommodate the population variation in disease onset and progression, which may also reflect an accumulation of environmental stressors and/or decreased protective nutrients that could function at the gene level (ie. epigenetic) or translational level for production and secretion of immune system molecules.

SUMMARY

Finally, the majority of studies of aging and periodontitis have emphasized the increased prevalence/severity of disease with aging, all based upon chronological age. However, evolving areas of study focusing on "biological aging" to help account for population variation in disease expression, may suggest that chronic periodontitis represents a co-morbidity that contributes to "gerovulnerability" within the population.

The oral microbiome and the immunobiology of periodontal disease and caries

The composition of the oral microbiome differs from one intraoral site to another, reflecting in part the host response and immune capacity at each site. By focusing on two major oral infections, periodontal disease and caries, new principles of disease emerge. Periodontal disease affects the soft tissues and bone that support the teeth. Caries is a unique infection of the dental hard tissues. The initiation of both diseases is marked by an increase in the complexity of the microbiome. In periodontitis, pathobionts and keystone pathogens such as Porphyromonas gingivalis appear in greater proportion than in health. As a keystone pathogen, P. gingivalis impairs host immune responses and appears necessary but not sufficient to cause periodontitis. Historically, dental caries had been causally linked to Streptococcus mutans. Contemporary microbiome studies now indicate that singular pathogens are not obvious in either caries or periodontitis. Both diseases appear to result from a perturbation among relatively minor constituents in local microbial communities resulting in dysbiosis. Emergent consortia of the minor members of the respective microbiomes act synergistically to stress the ability of the host to respond and protect. In periodontal disease, host protection first occurs at the level of innate gingival epithelial immunity. Secretory IgA antibody and other salivary antimicrobial systems also act against periodontopathic and cariogenic consortia. When the gingival immune response is impaired, periodontal tissue pathology results when matrix metalloproteinases are released from neutrophils and T cells mediate alveolar bone loss. In caries, several species are acidogenic and aciduric and appear to work synergistically to promote demineralization of the enamel and dentin. Whereas technically possible, particularly for caries, vaccines are unlikely to be commercialized in the near future because of the low morbidity of caries and periodontitis.

Periodontal disease immunology: 'double indemnity' in protecting the host

During the last two to three decades our understanding of the immunobiology of periodontal disease has increased exponentially, both with respect to the microbial agents triggering the disease process and the molecular mechanisms of the host engagement maintaining homeostasis or leading to collateral tissue damage. These foundational scientific findings have laid the groundwork for translating cell phenotype, receptor engagement, intracellular signaling pathways and effector functions into a 'picture' of the periodontium as the host responds to the 'danger signals' of the microbial ecology to maintain homeostasis or succumb to a disease process. These findings implicate the chronicity of the local response in attempting to manage the microbial challenge, creating a 'Double Indemnity' in some patients that does not 'insure' health for the periodontium. As importantly, in reflecting the title of this volume of Periodontology 2000, this review attempts to inform the community of how the science of periodontal immunology gestated, how continual probing of the biology of the disease has led to an evolution in our knowledge base and how more recent studies in the postgenomic era are revolutionizing our understanding of disease initiation, progression and resolution. Thus, there has been substantial progress in our understanding of the molecular mechanisms of host-bacteria interactions that result in the clinical presentation and outcomes of destructive periodontitis. The science has embarked from observations of variations in responses related to disease expression with a focus for utilization of the responses in diagnosis and therapeutic outcomes, to current investigations using cutting-edge fundamental biological processes to attempt to model the initiation and progression of soft- and hard-tissue destruction of the periodontium. As importantly, the next era in the immunobiology of periodontal disease will need to engage more sophisticated experimental designs for clinical studies to enable robust translation of basic biologic processes that are in action early in the transition from health to disease, those which stimulate microenvironmental changes that select for a more pathogenic microbial ecology and those that represent a rebalancing of the complex host responses and a resolution of inflammatory tissue destruction.

On-line liquid chromatography neutral loss-triggered electron transfer dissociationmass spectrometry for the targeted analysis of citrullinated peptides

Citrullination is a post-translational modification of proteins which deiminates arginine, increasing the mass by 0.98 Da. Protein citrullination is a known biomarker for multiple sclerosis and a potential biomarker for rheumatoid arthritis. Collision-induced dissociation (CID) tandem mass spectrometry of citrullinated peptides produces a dominant neutral loss of isocyanic acid (HNCO, -43 Da) from the deiminated arginine amino acid side-chain. Here we show that the loss of isocyanic acid in CID can be used as a trigger for targeted analysis by supplemental activation electron transfer dissociation (saETD). Unlike CID, post-translational modifications (PTMs) are retained on peptide backbone fragments produced by saETD, improving the confidence in assignment of both peptide sequence and PTM site. The method is demonstrated for four synthetic peptides spiked into complex trypsin-digested saliva samples and a commercial six protein tryptic mixture. In contrast to CID alone, the neutral-loss triggered ETD approach results in high confidence identification of three of the four peptides, including an unexpected disulfide-bound dimer, and zero false positives.

Initial comparison of proteomic profiles of whole unstimulated saliva obtained from generalized aggressive periodontitis patients and healthy control subjects

BACKGROUND AND OBJECTIVE

Salivary proteomics technology can be used to evaluate the disease progression of periodontitis and the systemic screening of proteomes of saliva from subjects with aggressive periodontitis has not been available. The objective of this preliminary study was to compare the proteomic profile of whole unstimulated saliva of subjects with generalized aggressive periodontitis (GAgP) with that of healthy volunteers to identify proteins, the levels of which were significantly altered between the two groups.

MATERIAL AND METHODS

Whole unstimulated saliva was obtained from five subjects with GAgP and five healthy subjects, and proteins were separated using two-dimensional gel electrophoresis. Proteins, the levels of which were significantly different between the two groups, were identified by computer image analyses and subsequent electrospray ionization tandem mass spectrometry.

RESULTS

Eleven proteins that exhibited a different level in the GAgP group vs. the control group were identified. Compared with whole saliva of healthy control subjects, the levels of serum albumin, immunoglobulin (Ig) gamma2 chain C region, Ig alpha2 chain C region, vitamin D-binding protein, salivary alpha-amylase and zinc-alpha2 glycoprotein were increased in whole unstimulated saliva of GAgP subjects, while those of lactotransferrin, elongation factor 2, 14-3-3 sigma, short palate, lung and nasal epithelium carcinoma-associated protein 2 precursor and carbonic anhydrase 6 were decreased.

CONCLUSION

Comparison of the proteomic profile of whole unstimulated saliva of GAgP subjects with that of healthy control subjects revealed at least 11 differential proteins. The approach applied herein might be helpful to aid understanding of the etiology of GAgP.

Antibody response after single-visit full-mouth ultrasonic debridementversusquadrant-wise therapy

INTRODUCTION

The aim of this study was to compare serum antibody responses to periodontal pathogens after single-visit full-mouth ultrasonic debridement and quadrant-wise therapy.

MATERIAL AND METHODS

Thirty-six subjects with chronic periodontitis were randomized into three groups: quadrant-wise debridement in four visits, one-visit full-mouth debridement with water and with povidone iodine. Blood samples were collected before and immediately after treatment and 1, 3 and 6 months post-therapy. Serum antibody titres and avidity to Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Treponema denticola were determined by enzyme-linked immunosorbent assay (ELISA) and thiocyanate ELISA, respectively.

RESULTS

IgG titres to P. gingivalis significantly decreased at 1, 3 and 6 months in full-mouth debridement with water group, while significant reductions were seen only at 3 and 6 months after quadrant-wise debridement. Both full-mouth groups showed significant reduction in IgG titres to A. actinomycetemcomitans at 3 and 6 months. Significant increases in antibody avidity to P. gingivalis and A. actinomycetemcomitans were noted 3 months following full-mouth debridement with povidone.

CONCLUSION

Both full-mouth and quadrant treatments generally resulted in a decrease in antibody titres and increase in antibody avidity. Full-mouth debridement induced an earlier reduction of IgG titre to P. gingivalis and A. actinomycetemcomitans, than quadrant-wise therapy.

Immune responses and vaccination against periodontal infections

BACKGROUND

The infectious aetiology of periodontitis is complex and no curative treatment modality exists. Palliative therapy is available.

AIMS

To review the evidence that active or passive immunization against periodontitis provides immune protection.

MATERIAL AND METHODS

PubMed (Medline), the National Institutes of Health, the Food and Drug Administration, and the Center for Disease Control electronic databases were searched to extrapolate information on immune responses to immunization against periodontitis.

RESULTS

Studies in non-human primate models using ligature-induced experimental periodontitis suggest that antibody responses by active immunization against Porphyromonas gingivalis can safely be induced, enhanced, and obtained over time. Immune responses to whole bacterial cell and purified protein preparations considered as vaccine candidates have been evaluated in different animal models demonstrating that there are several valid vaccine candidates. Data suggest that immunization reduces the rate and severity of bone loss. It is also, temporarily, possible to alter the composition of the subgingival microflora. Natural active immunization by therapeutic interventions results in antibody titre enhancement and potentially improves treatment outcomes. Passive immunization of humans using P. gingivalis monoclonal antibodies temporarily prevents colonization of P. gingivalis. Probiotic therapy may be an alternative approach. Regulatory and safety issues for human periodontal vaccine trials must be considered. Shared infectious aetiology between periodontitis and systemic diseases may enhance vaccine effort developments.

CONCLUSIONS

Proof of principle that active and passive immunization can induce protective antibody responses is given. The impact of natural immunization and passive immunization in humans should be explored and may, presently, be more feasible than active immunization studies.

Longitudinal stability of serum immunoglobulin G responses to periodontal bacteria

BACKGROUND

The value of seroepidemiology in the study of periodontal infections has not been adequately explored. This study examined serum immunoglobulin (IgG) responses to periodontal bacteria in patients with periodontitis and periodontitis-free individuals over a 30-month period.

METHODS

Eighty-nine patients with chronic periodontitis and 42 control subjects with no deep periodontal pockets and no or minimal attachment loss (30-72 years old, 43% men) were included. Patients were examined at baseline, after completed periodontal therapy 4 months post-baseline, and at 30 months, and controls, at baseline and 30 months. IgG antibodies to 19 periodontal species were determined by checkerboard immunoblotting.

RESULTS

On average, patients displayed at baseline up to 800-fold higher titers than controls to all but three species. Over the 30-month period, titers remained stable at low levels in controls. In patients, periodontal conditions improved from a baseline mean probing depth of 3.6 mm, bleeding on probing of 62% and an average of 21.5 pockets of=6 mm/person, to 2.5 mm mean pocket depth, 30% bleeding on probing, and 1.2 deep pockets, at 30 months. Over time, antibody titers showed a modest decline in patients, but remained significantly elevated at 30 months in comparison with controls. Antibody-level changes over time were not significantly different between subjects that did and did not receive adjunctive systemic antibiotics.

CONCLUSIONS

Conspicuous differences in IgG titers to periodontal bacteria exist between periodontitis patients and periodontally healthy controls. Despite successful periodontal therapy, titers remained elevated over a 30-month period, suggesting that serology may mark the history of past periodontal infection.

Granulocyte elastase activity in static and flow gingival crevicular fluid

OBJECTIVES

This study aimed to evaluate the volume of gingival crevicular fluid (GCF) and granulocyte elastase activity in static GCF (sGCF) and flow GCF (fGCF) from subjects with various periodontal conditions.

METHODS

Eleven periodontally healthy, 10 gingivitis and 12 periodontitis subjects were recruited and the sites investigated consisted of healthy sites from healthy subjects (HH); healthy (HG) and gingivitis sites (GG) from gingivitis subjects; and healthy (HP), gingivitis (GP) and periodontitis sites (PP) from periodontitis subjects. fGCF samples were collected either 1 min or 5 min following sGCF collection by paper strip technique. GCF volume was determined by Periotron 6000 and granulocyte elastase activity was assayed with a specific substrate [l-pyroglutamyl-l-prolyl-l-valine-p-nitroanilide(pGluProVal-pNA)].

RESULTS

At baseline, no significant differences existed in clinical and GCF parameters between the two matched sites for subsequent collection of fGCF samples either 1 min or 5 min after sGCF sampling in all subjects. The flow exudate in HG and HP sites quickly replenished to sGCF levels, while a delayed replenishment was found in HH sites, despite the similar sGCF volumes of these sites. The GCF volume and elastase levels in the fGCF at 1 min were higher in GP sites than in GG sites (P < 0.05). Overall, depletion of elastase levels in the fGCF at 1 min was observed in all subjects, whereas elastase levels in the fGCF at 5 min had replenished to sGCF levels in HP, GP, PP sites and GG sites, but had remained at a lower level in HH and HG sites. An overall positive correlation was found between sGCF and fGCF for GCF volume and elastase activity (P < 0.001); however, this correlation varied with GCF parameters and with site conditions of the subjects concerned.

CONCLUSIONS

This study shows that patterns of dynamic changes in GCF flow and elastase activity varied under different periodontal conditions. Assessment of both sGCF and fGCF may allow better insight into the dynamic change of the target components in GCF.

Estimation of serum antibody to subgingival species using checkerboard immunoblotting

Measurement of serum antibody to subgingival bacterial species has been useful in discriminating possible periodontal pathogens and in assessing the host's immune response to subgingival species. An immunoassay system was developed to measure the level of serum antibody to multiple subgingival species in multiple serum samples on a single nitrocellulose membrane. The principle steps of the assay are the following: 1) binding of antigens from bacterial preparations and protein A in parallel lanes on nitrocellulose membranes; 2) incubation of known concentrations of human immunoglobulin as well as various dilutions of serum from patients in lanes perpendicular to the antigen lanes; 3) incubation of the membrane with a peroxidase-conjugated second antibody; 4) detection of positive reactions by enhanced chemiluminescence. Emitted light was captured on a photographic film in which the positive reactions appeared as squares at the intersections of antigens with appropriate antibody. Antibody was quantified using a laser densitometer to compare the signal intensity of unknown samples with the ones generated by known amounts of human immunoglobulin captured on the same membrane. The assay permitted simultaneous screening and/or quantification of antibody in as many as 45 serum samples against up to 45 bacterial species. The mean and standard error of the coefficients of variation for replicates within an assay averaged 7.3 +/- 2.3%. Coefficients of variation of the assay run on different days for serum antibody to a range of subgingival species averaged 10.1 +/- 2.1%. Checkerboard immunoblotting is a simple and rapid immunoassay to permit quantification and/or screening of antibody to multiple subgingival species or antigens in multiple serum samples.

Active and alpha-1 proteinase inhibitor complexed leukocyte elastase levels in crevicular fluid from patients with periodontal diseases

Human leukocyte elastase is present in large amounts in the crevicular fluid of patients with periodontal disease and was considered as a putative biological marker of the evolution of such diseases. The aim of this work was to measure spectrophotometrically amounts of active elastase (AE) and elastase complexed to alpha 1 proteinase inhibitor (E-alpha 1-PI) in gingival crevicular fluid obtained, from patients suffering from rapidly progressive periodontitis (RPP group) or adult periodontitis (AP group) with different probing depths (3 to 5 mm and > 6 mm). AE and E-alpha 1-PI concentrations were negligible in healthy individuals. AE, but not E-alpha 1-PI, concentration appears to vary significantly with the probing depth in patients suffering either from rapidly progressive or adult periodontitis. No correlations were found between levels of AE and E-alpha 1-PI in the different groups of patients. AE concentration seems to be a marker of periodontal diseases in relation with probing depth.

Characterization of an adherence and antigenic determinant of the ArgI protease of Porphyromonas gingivalis which is present on multiple gene products

This study was performed to characterize the antigen(s) recognized by a panel of monoclonal antibodies (MAbs) produced to be specific for Porphyromonas gingivalis whole cells which we had previously shown to bind to epitopes recognized by sera from periodontitis patients. Preliminary data had suggested that the arginine-specific proteases of P. gingivalis (ArgI, ArgIA, and ArgIB) contained the antigenic determinants of four of these antibodies (MAbs 1A1, 2B/H9, 7D5, and 3B1). The location of the binding sites was examined with purified P. gingivalis enzymes and recombinant regions of the ArgI polyprotein expressed by subclones of the prpR1 gene in Escherichia coli XL-1 Blue cells. All four antibodies were reactive with protein determinants within the beta subunit, a hemagglutinin and/or adhesin component, of the ArgI dimer. MAb 1A1 strongly inhibited the agglutination of human erythrocytes by P. gingivalis W50 culture supernatant, suggesting that the binding site for this antibody contains residues which are critical for the interaction with the erythrocyte surface. The determinant for MAb 1A1 was examined further by construction of a set of truncated forms of the beta component expressed as fusion proteins with glutathione S-transferase at the N terminus. Analysis of these constructs mapped the binding site for MAb 1A1 to PrpRI residues G-907 to T-931, GVSPKVCKDV TVEGSNEFAP VQNLT. Western blot (immunoblot) analysis of P. gingivalis whole-cell proteins demonstrated that MAb 1A1 reacts with several proteins in the Mr range of 20,000 to 120,000. Furthermore, an oligonucleotide probe corresponding to the coding sequence for the region of the ArgI beta component containing the MAb 1A1 binding site hybridized to multiple bands on genomic digests of P. gingivalis DNA. These data indicate that the MAb 1A1 epitope may be a component of a binding domain common to multiple gene products of this organism and may thus represent a functionally important target of the host's specific immune response to P. gingivalis in periodontal disease.

The effects of a pulsed Nd:YAG laser on subgingival bacterial flora and on cementum: an in vivo study

The purpose of this study was to compare the effects of scaling and Nd:YAG laser treatments with that of scaling alone on cementum and levels of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola. Study samples consisted of 14 patients, age 30 to 75 years, 8 females and 6 males, with a total of 150 periodontally involved sites with probing depth > or = 5 mm. Group A consisted of 100 pockets that were subdivided into 4 equal groups that were treated with conventional scaling and pulsed Nd:YAG laser using an optic fiber of 300 microns and 4 different power levels as follows: Group 1: P = 0.8 W, f = 10 Hz, E = 100 mJ/pulse; Group 2: P = 1.0 W, f = 1.0 Hz, E = 100 mJ/pulse; Group 3: P = 1.2 W, f = 12 Hz, E = 100 mJ/purse; and Group 4: P = 1.5 W, f = 15 Hz, E = 100 mJ/pulse. The time of each treatment was 60 sec per pocket in all 4 groups. Group B consisted of 50 pockets that were treated by conventional scaling alone and served as a control group. Microbiological samples from group A were collected before scaling; after scaling = before laser, just after laser, 2 weeks later, 6 weeks later, and 10 weeks later. Microbiological samples from group B were collected before scaling, after scaling, 6 weeks later, and 10 weeks later. Microbiological analysis of all samples was done by the Institute Für Angewandte Immunologie (IAI) method. The effects of laser on root surfaces were assessed by SEM examination and the sample consisted of 13 teeth from 5 different patients. Four sets of 3 teeth each were treated with Nd:YAG laser using 0.8, 1.0, 1.2, and 1.5 W, respectively. One tooth was just scaled and not treated with laser to serve as a control. Microbiological analysis of Group A samples indicated posttreatment reduction in levels of all 4 bacterial types tested compared to pretreatment levels and Group B controls. SEM examination of the specimens treated with Nd:YAG laser at different levels exhibited different features of root surface alterations.

Effect of periodontal treatments on serum IgG antibody titers against periodontopathic bacteria

Serum IgG antibody titers to 7 periodontopathic bacteria in periodontitis patients were measured at the 1st visit and after various periodontal treatments with clinically successful improvement, in order to evaluate what kind of factors are associated with changes of serum antibody titers. 20 patients (10 male and 10 female from 23 to 61 years old) with adult, rapidly progressive periodontitis were enrolled in this study. All patients received initial preparation and most of them also underwent surgical procedure. After the treatments, the mean probing pocket depths decreased from 3.72 mm to 1.56 mm. Serum samples were collected from patients at the initial and final examinations. Serum IgG antibody titers against sonicated antigens of Porphyromonas gingivalis FDC 381, Prevotella intermedia ATCC 25611, Prevotella loescheii ATCC 15930, Fusobacterium nucleatum subspecies nucleatum ATCC 25586, Actinobacillus actinomycetemcomitans FDC Y4, Eikenella corrodens FDC 1073 and Capnocytophaga ochracea # M 12 were determined by enzyme-linked immunosorbent assay. The mean antibody titers to P. gingivalis and P. intermedia decreased significantly after the treatment as compared to their pretreatment levels. The antibody titer to P. gingivalis, especially, decreased in all of the patients examined. A significant relationship was found between the decreased antibody titer to P. gingivalis and the number of teeth which received periodontal surgery, as well as treatment length, and the relationship between the decreased antibody titer to P. intermedia and the number of extracted teeth was also significant. These results suggest that the changes of serum IgG titers against P. gingivalis and P. intermedia are related to the suppression of such pathogens in subgingival plague.

Treatment of subjects with refractory periodontal disease

The aim of the present study was to evaluate the effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects diagnosed with refractory periodontal disease. 21 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. When disease activity was detected, a bacterial sample was taken and a whole plaque susceptibility test was performed. Before the outcome of the susceptibility test the subjects were assigned to either antibiotic or placebo therapy. All subjects received scaling and rootplaning prior to antibiotic or placebo therapy. Based on the susceptibility test, subjects in the antibiotic group were treated either with Augmentin or clindamycin. The results demonstrated that in subjects with refractory periodontal disease there was no significant difference (N.S.) in the proportion of sites losing attachment before and after treatment (11.3% and 12.4%, respectively) over a 2-year post therapy observation period. However, the proportion of sites showing gain of attachment increased from 0.9% before therapy to 5.1% (p = 0.029) following selective antibiotic therapy when combined with scaling and rootplaning. The remainder of sites showed no change between pre- and post-therapy monitoring periods. The progression of attachment loss in the active sites could not be completely stopped over the entire 2-year period. After 12-15 months following therapy, there was a tendency towards new loss of attachment and an increase of pocket depth. However, all 4 subjects treated with placebo drug demonstrated continuous deterioration and had to be retreated. Although the proportion of sites losing attachment decreased from 5.1% to 2.3% (N.S.), the proportion of sites gaining attachment also decreased from 2.0% to 1.0% (N.S.). The results suggest that scaling and rootplaning together with selected antibiotic therapy repeated every 12-15 months may be beneficial for these subjects although it may not completely stop progressive attachment loss.