Correlation of histometric, microbial, and clinical indicators of periodontal disease status before and after root planing

Periodontal granulation tissue - To remove or not to remove, that is the question

Formation of granulation tissue is a fundamental phase in periodontal wound healing with subsequent maturation leading to regeneration or repair. However, persistently inflamed granulation tissue presents in osseous defects as a result of periodontitis and is routinely disrupted and discarded with non-surgical and surgical therapy to facilitate wound healing or improve chances of regeneration. Histological assessment suggests that granulation tissue from periodontitis-affected sites is effectively a chronic inflammatory tissue resulting from impaired wound healing due to persistence of bacterial dysbiotic bioflim. Nevertheless, the immunomodulatory potential and stem cell characteristics in granulation tissue have also raised speculation about the tissue's regenerative potential. This has led to the conception and recent implementation of surgical techniques which preserve granulation tissue with the intention of enhancing innate regenerative potential and improve clinical outcomes. As knowledge of fundamental cellular and molecular functions regulating periodontitis-affected granulation tissue is still scarce, this review aimed to provide a summary of current understanding of granulation tissue in the context of periodontal wound healing. This may provide new insights into clinical practice related to the management of granulation tissue and stimulate further investigation.

The adjunctive effect of probiotics to nonsurgical treatment of chronic periodontitis: A randomized controlled clinical trial

Background:

Probiotics catch more attention as adjunctive periodontal therapy. This study was conducted to assess the benefit of locally delivered Lactobacillus reuteri (L. reuteri) probiotic as an adjunctive to scaling and root planing (SRP) in the treatment of chronic periodontitis clinically and microbiologically.

Materials and Methods:

Bacterial cultures and clinical evaluation were recorded in 20 sites of chronic periodontitis in 12 patients and followed up at 3 and 6 months from the start of intervention using clinical attachment level, probing pocket depth, plaque index (PI), bleeding on probing, and microbiologically for Porphyromonas gingivalis (P. gingivalis) load. Patients meeting the inclusion criteria were scheduled within 1 week for two sessions of SRP. After SRP, oral hygiene measures were reassured, and sites were divided randomly into two groups 10 sites each. Group I received SRP only, while Group II received SRP and subgingival delivery of 1 ml of probiotic L. reuteri suspension at baseline and 1, 2, and 4 weeks using a blunt syringe. A periodontal pack was applied after the placement of the drug.

Results:

We found noticeable variation between the two groups in all evaluation aspects at 3 and 6-month follow-up periods except PI at 6 months in which there was no significant difference between both groups.

Conclusions:

The results proved the antimicrobial benefit of L. reuteri probiotic as a promising adjunctive therapy in improving periodontal parameters. However, further long-term studies with large sample size are needed to evaluate the extent of the added value of L. reuteri suspension.

Antibacterial Activity of Boswellia sacra Flueck. Oleoresin Extract against Porphyromonas gingivalis Periodontal Pathogen

Boswellia sacra Flueck. oleoresin extract (frankincense) has traditionally been used in the treatment of different diseases, but there are no sufficient studies on its potential activity against periodontal pathogens. Therefore, antibacterial and antibiofilm activity of frankincense extract against Porphyromonas gingivalis clinical isolates were studied. The phytochemical composition of the volatile components of the extract was identified by GC-MS analysis revealing 49 compounds as trans-nerolidyl formate, cycloartenol acetate, ursenoic acid 3-oxomethyl ester, bisabolene epoxide, and kaur-16-ene. It decreased the growth and increased the leakage of nucleotides in 58.3% and 33.3% of isolates, respectively. Additionally, it reduced the extracellular polysaccharide production and the cell surface hydrophobicity in 41.67% and 50% of the isolates, respectively. Crystal violet assay revealed inhibition of biofilm formation by the tested isolates. Light microscope and scanning electron microscope were used to examine the biofilms and they confirmed the reduction of biofilm formation by frankincense extract. Downregulation of the genes linked to biofilm formation (fimA, hagA, and hagB) was observed using qRT-PCR after treatment with the frankincense extract. This study suggested that the frankincense extract could exhibit antibacterial and antibiofilm activity against P. gingivalis isolates. Thus, the frankincense extract could be used as a treatment approach for periodontitis.

The effect of drug dose and duration of adjuvant Amoxicillin-plus-Metronidazole to full-mouth scaling and root planing in periodontitis: a systematic review and meta-analysis

OBJECTIVES

The aim is to explore the optimal drug dose and duration of adjunctive Amoxicillin-plus-Metronidazole (AMX/MET) to full-mouth scaling and planing (FMSRP) in periodontitis.

METHODS

An electronic search in four databases and manual search in four journals were conducted for randomised clinical trials comparing AMX/MET adjunct to FMSRP with FMSRP alone for at least 3 months.

RESULTS

Eleven studies were eligible and included. The primary outcome was clinical attachment level (CAL) gain, the secondary outcomes were periodontal pocket depth (PPD) reduction and adverse events. Our results showed a beneficial effect of adjunctive AMX/MET with higher drug dose to FMSRP for CAL gain and PPD reduction at 3 months, and the benefit remained stable at 6 months. However, minimal difference among three-seven-and ten-day drug duration was observed. In addition, the risk difference of adverse events was minimal between two groups.

CONCLUSION

FMSRP adjunct to a high drug dose of 500/500 mg of AMX/MET showed a significant and stable improvement on 6-month follow-up period. No decision for drug duration could be made due to limited evidence.

CLINICAL RELEVANCE

On 6-month follow-up, higher dose of AMX/MET adjunct to FMSRP could provide a stable clinical effect. No recommendation for drug duration could be made.

The effects of intensive oral care before surgery for gastric cancer patients

OBJECTIVES

Oral function management has been recognized as important strategy for preventing postoperative complications. In this historical cohort study, we focused on the patients who planed gastrectomy, and investigated the appropriate duration and frequency of preoperative oral care to prevent complications after surgery.

METHODS

Patients who planed surgery for gastric cancer between 2012 and 2018 were enrolled. We defined intensive oral care (IOC) as initial intervention at least three weeks before surgery and follow-up intervention within a week before surgery. As the primary outcome, the incidence of postoperative infectious complications was compared between the IOC and non-intensive oral care groups.

RESULTS

A total of 576 patients were enrolled, including 66 with IOC. The incidence of infectious complications was 2/66 (3.0%) in the IOC group and 64/510 (12.5%) in the non-intensive oral care group. After adjusting for confounding factors, patients with IOC exposure had a lower chance of developing postoperative infectious complications (odds ratio; 0.217, 0.051-0.927).

CONCLUSIONS

Intensive oral care can help prevent postoperative infectious complications after gastrectomy. These findings suggest that appropriate preoperative oral care includes at least two interventions: three weeks or more before and within one week before surgery.

Shifts of subgingival bacterial population after nonsurgical and pharmacological therapy of localized aggressive periodontitis, followed for 1 year by Ion Torrent PGM platform

The possibility of targeting the hypervariable region V3 of the 16S rRNA gene using Ion Torrent Personal Genome Machine (PGM) could provide a complete analysis of subgingival plaque samples, potentially able to identify microbiological species missed by culture-based methods. A 16-year-old female smoker patient, affected by localized aggressive periodontitis, underwent a full-mouth disinfection protocol and was inserted in a 3-month recall program. Microbiological samples were collected at baseline and at 30, 100, 365 days follow-up and analyzed by Ion Torrent PGM. Capnocytophaga, Fusobacterium, Prevotella, and Treponema were the most represented pathogens at baseline. Nonsurgical treatment and systemic antibiotics drastically lowered the anaerobic species, and their presence remained limited after 100 days, while a consistent recolonization by anaerobic bacteria was detected at 365 days. The patient showed a general improvement of periodontal conditions. Differently from polymerase chain reaction and other microarray techniques, Ion Torrent performs a quantitative analysis of the microbiota, irrespective of the searched species. An accurate definition of the shifts of the bacterial community might help periodontal researchers for a better understanding of the impact of different treatment approaches or in intercepting nonresponsive conditions.

Long-term clinical response to treatment and maintenance of localized aggressive periodontitis: a cohort study

AIM

To evaluate long-term clinical response to periodontal therapy and maintenance in localized aggressive periodontitis (LAP).

MATERIALS AND METHODS

One hundred forty-one African Americans diagnosed with LAP, aged 5-25 years, were enrolled. Patients underwent periodontal mechanical debridement plus 1 week of amoxicillin/metronidazole. Mechanical therapy was repeated as needed and clinical parameters were recorded at baseline, 3, 6, 12, 18 and 24 months, and two additional annual follow-up visits after treatment. Radiographs from primary dentition of patients with LAP in permanent dentition, and additional healthy siblings (HS) were analysed retrospectively.

RESULTS

Periodontal therapy significantly improved probing depth and clinical attachment level up to 4 years (mean reductions: 2.18 ± 1.03 and 2.80 ± 1.43 mm, respectively). Percentage of affected sites was reduced at all time points and maintained up to 4 years. Non-compliance with antibiotics/appointments negatively affected the treatment response. Ninety per cent of LAP patients in permanent dentition and 32% of HS presented radiographic bone loss in primary dentition.

CONCLUSIONS

Mechanical debridement with 1 week of systemic antibiotics along with proper periodontal maintenance was effective in the treatment and successful maintenance of LAP for up to 4 years. LAP in permanent dentition may be preceded in the primary dentition. Clinicaltrials.gov #NCT01330719.

Activation and resolution of periodontal inflammation and its systemic impact

Inflammation is a highly organized event impacting upon organs, tissues and biological systems. Periodontal diseases are characterized by dysregulation or dysfunction of resolution pathways of inflammation that results in failure to heal and in a dominant chronic, progressive, destructive and predominantly unresolved inflammation. The biological consequences of inflammatory processes may be independent of the etiological agents, such as trauma, microbial organisms and stress. The impact of the inflammatory pathological process depends upon the tissues or organ system affected. Whilst mediators are similar, there is tissue specificity for the inflammatory events. It is plausible that inflammatory processes in one organ could directly lead to pathologies in another organ or tissue. Communication between distant parts of the body and their inflammatory status is also mediated by common signaling mechanisms mediated via cells and soluble mediators. This review focuses on periodontal inflammation, its systemic associations and advances in therapeutic approaches based on mediators acting through orchestration of natural pathways to resolution of inflammation. We also discuss a new treatment concept in which natural pathways of resolution of periodontal inflammation can be used to limit systemic inflammation and promote healing and regeneration.

Clinical changes in periodontal subjects with the probiotic Lactobacillus reuteri Prodentis: a preliminary randomized clinical trial

OBJECTIVES

The aim of this study was to assess the clinical effect of the administration of Lactobacillus reuteri Prodentis as a probiotic agent in the treatment of initial to moderate chronic periodontitis. Secondary objectives were to evaluate the patient 'compliance' factor and to observe the potential side-effects of the probiotic agent.

MATERIALS AND METHODS

Twenty systemically healthy, non-smoking subjects with initial-to-moderate chronic periodontitis were enrolled in this 1-month double-blind, placebo-controlled, randomized clinical trial. Subjects were randomly assigned to receive tablets containing Lactobacillus reuteri Prodentis or placebo once a day for 30 days. Clinical parameters were collected at baseline and 30 days post-treatment.

RESULTS

Periodontal clinical parameters were improved in the test group after a 30-day intervention. The test group demonstrated a statistically significant reduction (p < 0.05) in all the periodontal parameters included in the study (plaque index, bleeding on probing and pocket probing depths), while the control group treated with placebo did not show any statistically significant change in periodontal parameters.

CONCLUSIONS

These data indicate that oral administration of Lactobacillus reuteri Prodentis improved the short-term clinical outcomes in non-smoking patients with initial-to-moderate chronic periodontitis.

Treatment modalities and evaluation models for periodontitis

Periodontitis is the most common localized dental inflammatory disease related with several pathological conditions like inflammation of gums (gingivitis), degeneration of periodontal ligament, dental cementum and alveolar bone loss. In this perspective, the various preventive and treatment modalities, including oral hygiene, gingival irrigations, mechanical instrumentation, full mouth disinfection, host modulation and antimicrobial therapy, which are used either as adjunctive treatments or as stand-alone therapies in the non-surgical management of periodontal infections, have been discussed. Intra-pocket, sustained release systems have emerged as a novel paradigm for the future research. In this article, special consideration is given to different locally delivered anti-microbial and anti inflammatory medications which are either commercially available or are currently under consideration for Food and Drug Administration (FDA) approval. The various in vitro dissolution models and microbiological strain investigated to impersonate the infected and inflamed periodontal cavity and to predict the in vivo performance of treatment modalities have also been thrashed out. Animal models that have been employed to explore the pathology at the different stages of periodontitis and to evaluate its treatment modalities are enlightened in this proposed review.

Assessments of salivary antioxidant activity using electron spin resonance spectroscopy

OBJECTIVE

In recent years, the function of saliva has been focused on evaluation of general status. The relationship between salivary antioxidant activity and periodontal disease progression is unclear. The aim of this study is to assess the relationship between periodontal disease and salivary antioxidant activity towards various reactive oxygen species (ROS) using electron spin resonance (ESR) technique.

METHODS

We demonstrated that whole saliva derived rats or human subjects scavenged ROS such as superoxide (O(2)(·-)) and hydroxyl radical (HO(·)) using ESR spectroscopy with spin trapping agent. In addition, we assessed the relationship between antioxidants activity towards ROS and periodontal index with superoxide dismutase (SOD) activity in human subject saliva.

RESULTS

Antioxidant activity towards O(2)(·-) was increased by Porphyromonas gingivalis (P. gingivalis) infection in rat, although antioxidant activity towards HO(·) was not changed. In human, a strong correlation (r = 0.88, p < 0.01) recognized between salivary antioxidant activity towards O(2)(·-) and probing pocket depth (PPD). In addition, the intensity of salivary antioxidant activity depended on SOD activity level. SOD activity was also correlated with PPD.

CONCLUSIONS

Rat salivary antioxidant activity towards O(2)(·-) was up-regulated by the inflammatory response caused by P. gingivalis infection. Similar response was recognized in human saliva with periodontal index. Additionally, a linear correlation between antioxidant activity towards O(2)(·-) and SOD activity was verified by ESR technique. Therefore, evaluation of the salivary antioxidant activity towards O(2)(·-) might be an effective parameter for the objective assessment of periodontal disease progression.

Paradigm shift in the pharmacological management of periodontal diseases

It is becoming clear that variations in inflammatory response are a major determinant in susceptibility to periodontitis. However, our understanding of the relationship of the causal agents in periodontitis to the pathogenesis is not as clear as we once thought, and thus therapies based on etiopathogenesis are similarly in question. We are entering a new era of therapeutic discovery that may have a major impact on our management of the periodontal diseases. Fundamentally, periodontitis is an irreversible condition and once both soft and hard tissues are lost, the healthy periodontal architecture cannot be completely or predictably rebuilt. The discovery of new families of lipid mediators of resolution of inflammation (the lipoxins) and eicosapentaenoic-acid- and docosahexaenoic-acid-derived chemical mediators (the resolvins and protectins) opens new avenues to designing resolution-targeted therapies to control the unwanted side effects of excessive inflammation. The novel protective and therapeutic actions of pro-resolution lipid mediators following microbial challenge are mediated by regulation of the local and systemic inflammatory response that has a direct impact on the organization of the biofilm (plaque) and suggests a new paradigm in clinical periodontal therapeutics.

Do probiotics offer opportunities to manipulate the periodontal oral microbiota?

BACKGROUND

As in other fields of healthcare, probiotics have been introduced for prevention and treatment of periodontal diseases.

OBJECTIVE

This review was initiated to explore whether the use of probiotics can influence the periodontal microbiota and periodontal health.

MATERIALS AND METHODS

Literature on the mode of action of oral probiotics was reviewed and a systematic review was performed on the microbiological and clinical effects of oral probiotics on periodontal health.

RESULTS

Three animal and 11 in vivo human studies were retrieved. Six studies reported on microbiological effects whereas eight studies report on clinical effects. Seven studies were performed on healthy or gingivitis patients and four studies on periodontitis patients. Many of the retrieved studies are pilot in nature and with low quality. The high degree of heterogeneity between studies hampered analysis.

CONCLUSION

Taking into consideration all limitations, the currently available data indicate an effect of probiotics on the oral microbiota and a more limited effect on clinical periodontal outcome measures. However, there is an urgent need for properly conducted clinical trials where probiotics are used as adjuncts to standard periodontal care, similar to antibiotics, using probiotic strains with, at least at an in vitro level, proven periodontal probiotic effects.

Transcriptomes in healthy and diseased gingival tissues

BACKGROUND

Clinical and radiographic measures are gold standards for diagnosing periodontitis but offer little information regarding the pathogenesis of the disease. We hypothesized that a comparison of gene expression signatures between healthy and diseased gingival tissues would provide novel insights in the pathobiology of periodontitis and would inform the design of future studies.

METHODS

Ninety systemically healthy non-smokers with moderate to advanced periodontitis (63 with chronic periodontitis and 27 with aggressive periodontitis) each contributed at least two diseased interproximal papillae (with bleeding on probing [BOP], probing depth [PD] > or =4 mm, and attachment loss [AL] > or =3 mm) and a healthy papilla, if available (no BOP, PD < or =4 mm, and AL < or =2 mm). RNA was extracted, amplified, reverse-transcribed, labeled, and hybridized with whole genome microarrays. Differential expression was assayed in 247 individual tissue samples (183 from diseased sites and 64 from healthy sites) using a standard mixed-effects linear model approach, with patient effects considered random with a normal distribution and gingival tissue status considered a two-level fixed effect. Gene ontology analysis classified the expression patterns into biologically relevant categories.

RESULTS

Transcriptome analysis revealed that 12,744 probe sets were differentially expressed after adjusting for multiple comparisons (P <9.15 x 10(7)). Of those, 5,295 were upregulated and 7,449 were downregulated in disease compared to health. Gene ontology analysis identified 61 differentially expressed groups (adjusted P <0.05), including apoptosis, antimicrobial humoral response, antigen presentation, regulation of metabolic processes, signal transduction, and angiogenesis.

CONCLUSION

Gingival tissue transcriptomes provide a valuable scientific tool for further hypothesis-driven studies of the pathobiology of periodontitis.

Guiding periodontal pocket recolonization: a proof of concept

The complexity of the periodontal microbiota resembles that of the gastro-intestinal tract, where infectious diseases are treatable via probiotics. In the oropharyngeal region, probiotic or replacement therapies have shown some benefit in the prevention of dental caries, otitis media, and pharyngitis, but their effectiveness in the treatment of periodontitis is unknown. Therefore, this study addressed the hypothesis that the application of selected beneficial bacteria, as an adjunct to scaling and root planing, would inhibit the periodontopathogen recolonization of periodontal pockets. Analysis of the data showed, in a beagle dog model, that when beneficial bacteria were applied in periodontal pockets adjunctively after root planing, subgingival recolonization of periodontopathogens was delayed and reduced, as was the degree of inflammation, at a clinically significant level. The study confirmed the hypothesis and provides a proof of concept for a guided pocket recolonization (GPR) approach in the treatment of periodontitis.

Microbiological findings after periodontal therapy using curettes, Er:YAG laser, sonic, and ultrasonic scalers

AIM

To evaluate and compare the microbiological effects of hand instruments, Er:YAG-laser, sonic, and ultrasonic scalers in patients with chronic periodontitis. Patient perception of each treatment was documented.

MATERIAL AND METHODS

From 72 patients, bacterial samples were collected from the deepest pocket in each quadrant (total: 288 sites). A polymerase chain reaction kit estimated the amount of Aggregatibacter (Actinobacillus) actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), and Treponema denticola (Td) at baseline as well as 3 and 6 months after therapy. One quadrant in each patient was randomly assigned to curettes (H-group), Er:YAG laser (L-group), sonic device (S-group), or ultrasonic device (U-group).

RESULTS

Three months post-operatively, the amounts of Pg, Pi, Tf, and Td were significantly reduced in all groups. Laser and sonic instrumentation failed to reduce Aa. Six months after therapy, significant differences were still detected for Pg (L- and U-group), for Pi and Tf (S-group), and for Td (L-, S- and U-group). Patients rated ultrasonic treatment as more preferable than hand and laser instrumentation.

CONCLUSION

The various treatment methods resulted in a comparable reduction of the evaluated periodontal pathogens, and bacterial increase was only partially different 6 months post-operatively. Ultrasonic instrumentation caused less discomfort.

Benefit of “one-stage full-mouth disinfection” is explained by disinfection and root planing within 24 hours: a randomized controlled trial

OBJECTIVES

The beneficial effects of the one-stage, full-mouth disinfection remain controversial in the scientific literature. This might be due to the fact that an entire mouth disinfection with the use of antiseptics has been confused with a full-mouth scaling and root planing. This parallel, single blind RCT study aimed to compare several full-mouth treatment strategies with each other.

MATERIAL AND METHODS

Seventy-one patients with moderate periodontitis were randomly allocated to one of the following treatment strategies: scaling and root planing, quadrant by quadrant, at two-week intervals (negative control, NC), full-mouth scaling and root planing within 2 consecutive days (FRP), or three one-stage, full-mouth disinfection (FM) protocols within 2 consecutive days applying antiseptics to all intra-oral niches for periopathogens using as antiseptics: chlorhexidine (FMCHX) for 2 months, amine fluoride/stannous fluoride for 2 months (FMF), or chlorhexidine for 2 months followed by amine fluoride/stannous fluoride for another 6 months (FMCHX+F). At baseline and after 2, 4, and 8 a series of periodontal parameters were recorded.

RESULTS

All treatment strategies resulted in significant (p<0.05) improvements of all clinical parameters over the entire duration of the study. Inter-treatment differences were often encountered. The NC group nearly always showed significant smaller improvements than the two CHX groups. The differences between the FRP or FM groups, and the two CHX groups only sporadically reached a statistical significance.

CONCLUSION

These observations indicate that the benefits of the "OSFMD" protocol are partially due to the use of the antiseptics and partially to the completion of the therapy in a short time.

Effect of mechanical and antiseptic therapy on peri-implant mucositis: an experimental study in monkeys

OBJECTIVES

This experiment was performed to evaluate clinically and histologically the effect of mechanical therapy with or without antiseptic therapy on peri-implant mucositis lesions in nine cynomolgus monkeys.

MATERIAL AND METHODS

Two ITI titanium implants were inserted into each side of the mandibles. After 90 days of plaque control and soft tissue healing, a baseline clinical examination was completed. Peri-implant lesions were induced by placing silk ligatures and allowing plaque to accumulate for 6 weeks. The clinical examination was then repeated, and the monkeys were randomly assigned to three treatment groups: group A, mechanical cleansing only; group B, mechanical cleansing and local irrigation with 0.12% chlorhexidine (CHX) and application of 0.2% CHX gel; and group C, control, no treatment. The implants in treatment groups A and B were treated and maintained according to the assigned treatment for two additional months. At the end of the maintenance period, a final clinical examination was performed and the animals were sacrificed for biopsies.

RESULTS

The mean probing depths (PD) values at mucositis were: 3.5, 3.7, and 3.4 mm, and clinical attachment level (CAL) = 3.8, 4.1, and 3.9 mm for treatment groups A, B and C, respectively. The corresponding values after treatment were: PD = 1.7, 2.1, and 2.5 mm, and CAL=2.6, 2.6, and 3.1 mm. ANOVA of mean changes (Delta) in PD and CAL after treatment showed no statistical difference between the treatment groups. Comparison of the mean changes in PD and CAL after treatment yielded statistical differences between the control and treatment groups P < 0.01. According to the t-test, no statistical difference was found between treatment groups A and B for the PD reduction but there was a significant difference for the CAL change, P < 0.03. Group A had significantly more recession and less CAL gain than group B. Non-parametric tests yielded no significant differences in modified plaque index (mPlI) and gingival index (GI) after treatment between both treatment groups. Frequencies and percent distributions of the mPlI and GI scores changed considerably for both treatment groups when compared with the changes in the control group after treatment. With regard to the histological evaluation, no statistical differences existed between the treatments for any linear measurement. The proportion of inflammation found in the mucosal tissues of the control implants was greater than the one found for both treatment groups, P < 0.01. More importantly, both treatment groups showed a similar low proportion of inflammation after 2 months of treatment.

CONCLUSIONS

Within the limitations of this experiment, and considering the supportive plaque control rendered, it can be concluded that for pockets of 3-4 mm: (1) mechanical therapy alone or combined with CHX results in the clinical resolution of peri-implant mucositis lesions, (2) histologically, both treatments result in minimal inflammation compatible with health, and (3) the mechanical effect alone is sufficient to achieve clinical and histologic resolution of mucositis lesions.

Initial subgingival colonization of 'pristine' pockets

The treatment of periodontitis/peri-implantitis involves the reduction/eradication of periopathogens. After therapy, beneficial and pathogenic species recolonize the subgingival area. The dynamics of recolonization and especially the role of the supragingival environment in this process are still not well-understood. This prospective, split-mouth study followed the early colonization of 'pristine' pockets created during implant surgery (16 partially edentulous patients), to record the time needed before a complex subgingival flora could be established with the supragingival area as the single source. Four subgingival plaque samples were taken from shallow and medium pockets around implants (test), and neighboring teeth (undisturbed microbiota as reference) 1, 2, and 4 wks after abutment connection. Checkerboard DNA-DNA hybridization and culture data revealed a complex microbiota (including several pathogenic species) in the pristine pockets within a wk, with a minimal increase in counts up to 4 wks. Analysis of these data demonstrated that, even with the supragingival environment as the single source for colonizing bacteria, a complex subgingival microbiota can develop within 1 wk.

Effects of Non-Surgical Mechanical Therapy on the Subgingival Microbiota of Brazilians With Untreated Chronic Periodontitis: 9-Month Results

BACKGROUND

Mechanical periodontal therapy is the most common treatment of periodontal infections. It is directed primarily towards removing biofilm and calculus from the root surfaces, leading to ecological changes in the subgingival environment. Thus, the purpose of this study was to evaluate the effects of scaling and root planing (SRP) on the subgingival microbiota of Brazilian subjects with untreated chronic periodontitis over a 9-month period.

METHODS

Twenty-five untreated chronic periodontitis patients (mean age 43 +/- 5 years; 20% smokers; 45% males) were selected from a Brazilian population. At baseline, probing depth (PD), clinical attachment level (CAL), visible supragingival biofilm (SB), bleeding on probing (BOP), and suppuration (SUP) were measured at six sites/tooth. Subgingival plaque samples were obtained from 10 sites with the deepest PD (> or =5 mm) of each subject and tested for the presence of 25 oral species by DNA probes and the checkerboard technique. Patients received full mouth SRP and oral hygiene instructions. Clinical and microbiological assessments were repeated at 3, 6, and 9 months after therapy. During this period, all patients received maintenance therapy, including supragingival prophylaxis and reinforcement in home care procedures. The clinical and microbiological parameters examined were computed for each subject and at each visit. Differences over time were sought using the Friedman test.

RESULTS

Significant reductions in mean CAL and PD (P <0.01), percent of sites with SB (P <0.01), BOP and SUP (P <0.05) were observed during the course of the study. In general, microbial changes were more pronounced for the mean counts than for the frequency of the microorganisms, particularly at 3 months post-therapy. Significant reductions in prevalence and levels were observed for certain periodontal pathogens including P. gingivalis (P <0.05; P <0.01), T. forsythensis (P <0.01), C. rectus (P <0.01), and A. actinomycetemcomitans (P <0.01; P <0.05). Nevertheless, the frequency of A. actinomycetemcomitans increased to baseline values at 9 months after therapy. Treponema ssp. and Prevotella spp. showed a modest decrease in prevalence, whereas marked reductions in their levels were observed. In contrast, the frequency and counts of the suspected pathogens P. micros and F. nucleatum increased after treatment. Species considered beneficial including Actinomyces spp., some oral streptococci, and V. parvula increased in prevalence, although these two last species tended to return to baseline levels at 9 months.

CONCLUSION

In Brazilians with untreated chronic periodontitis, SRP led to clinical improvement associated with a decrease of certain periodontal pathogens, and an increase of beneficial species for up to 9 months after therapy.

Microbial shifts after subgingival debridement and formation of bacterial resistance when combined with local or systemic antimicrobials

Antibiotics have played a major role in the improvement of life expectancy in the last 50 years and have led many to believe that bacterial infections were about to vanish as a disease entity of any importance. Emerging problems resulting from a widespread use of antibiotics have modified the general perception of the capabilities of antimicrobial agents. Over the years, bacteria have become increasingly resistant to formerly potent antimicrobial agents, including some antiseptics. The use of antimicrobials may also disturb the delicate ecological equilibrium of the body, allowing the proliferation of resistant bacteria or non-bacterial micro-organisms. This shift may initiate new infections that are worse than the ones originally treated. No antimicrobial drug is absolutely non-toxic and the use of an agent carries accompanying risks. This paper discusses the development and occurrence of antimicrobial resistance in the subgingival flora towards antiseptics and local or systemic antibiotics and is focussed on the question: how can the outcome of periodontal therapy with/without antimicrobials be improved?

Clinical versus statistical significance as they relate to the efficacy of periodontal therapy

BACKGROUND

The author discusses the shortcomings of using statistical significance testing as a method to infer that results of periodontal clinical trials are clinically meaningful. To compensate for these deficiencies, he also identifies criteria and periodontal parameters that can be used to reflect clinically significant outcomes.

TYPES OF STUDIES REVIEWED

The author searched the medical and dental literature to identify commentaries that addressed the problems associated with interpreting statistical significance testing, or hypothesis testing, and defining clinical significance.

RESULTS

The limitations of statistical significance testing related to identifying clinically significant changes include failure to indicate if the detected differences between variables in test and control groups are large or important. After reviewing various definitions of the term "clinical significance," the author reviews and proposes a comprehensive working definition of it. Regarding the efficacy of periodontal therapy, he delineates the advantages and limitations of specific criteria (such as absolute values, cut points) that can be used to define clinical significance.

CLINICAL IMPLICATIONS

The author suggests that clinically significant results should be defined before initiating a study and statistical significance testing should be used to validate that findings did not occur by chance. This would help place the importance of clinical data into perspective, and it would enhance clinicians' ability to select the most appropriate therapies for particular sites in periodontal patients.

Clinical significance of non-surgical periodontal therapy: an evidence-based perspective of scaling and root planing

Analysis of Egyptian hieroglyphics and medical papyri indicate that non-surgical periodontal treatment was common 3000-4000 years ago. Even today, scaling and root planing (SRP) remains an essential part of successful periodontal therapy. The collective evidence from numerous clinical trials reveals a consistency of clinical response in the treatment of chronic periodontitis by SRP using manual, sonic, or ultrasonic instrumentation. Thus, SRP remains the 'gold standard' to which more recently developed therapeutic modalities must be compared. Inherent to the clinical evaluation of SRP are such concerns as manual versus sonic and ultrasonic instrumentation, control of sub-gingival bacterial populations, removal of calculus, root smoothness and changes in various clinical parameters, e.g. probing depth, attachment levels, bleeding on probing and gingival inflammation. Lastly, an abbreviated discussion is presented on a relatively new paradigm of complete mouth 'disinfection' in a compressed time-frame that includes SRP as a significant component of the treatment regimen.

Antimicrobial effects of mechanical debridement

Self-performed plaque removal using manual or powered toothbrushes and interdental cleaning devices is improved in subjects that have received oral hygiene instructions. Personal oral hygiene coupled with regular professional supragingival debridement may further improve the level of plaque control but still fails to achieve a completely plaque-free dentition. Both patient-performed and professional supragingival plaque removal has an effect on subgingival microbiota that is limited to the marginal 3 mm of the periodontal pocket. At sites with 4 mm or more of probing depth, only subgingival scaling leads to a significant reduction of the bacterial load. The subgingival microflora can be further reduced by pocket elimination surgery. Due to the sequence of bacterial recolonization that occurs following mechanical debridement, the level of periodontal pathogens such as B. forsythus, P. gingivalis and T. denticola may be reduced for several months. Mechanical debridement also influences the patient's immune system response, resulting in antibody titers and avidity against periodontal pathogens. As a basis for the restoration and maintenance of periodontal health, repeated subgingival debridement, as performed in supportive periodontal therapy, can reduce the number and proportions of periodontopathogenic bacteria in subgingival plaque. However, intensive subgingival scaling and root planing should be avoided in sites that probe less than 3 mm, as this is likely to traumatize the periodontium and cause attachment loss.

The significance of prior mechanical therapy for changes of periodontal status achieved by local delivery of a doxycyclinehyclate containing gel

AIM

The purpose of this retrospective analysis was to examine what effect, if any, the time elapsed between an individual's last episode of scaling and root planing and subsequent treatment with a sustained-release doxycycline hyclate gel (DH) alone or scaling and root planing alone (SRP) would have upon adult periodontitis.

METHODS

A total of 207 subjects were included in the DH group and 210 patients in the SRP group. Periodontitis was defined as those sites which presented with pocket depths > or =5 mm and exhibited bleeding upon probing. In both DH and SRP groups, 3 sub-groups of subjects were identified according to their last episode of scaling and root planing prior to the study baseline: within 2 to 6 months, >6 but < or =12 months, and one or more times in their life but not within the last 12 months. Each study site was treated twice over a 9-month study period, once at baseline and again at 4 months. Data from the study sites at 4, 6, and 9 months were then evaluated for changes in probing depth, clinical attachment level, and bleeding upon probing.

RESULTS

At the 9-month evaluation, all sub-groups in the DH and SRP treatment arms presented with improvement in the measured clinical parameters, as compared to baseline. No significant differences were observed in the measured periodontal indices among the study sites between the three sub-groups for either treatment.

CONCLUSIONS

It is concluded that the time interval since the last episode of scaling and root planing had no observable effect on the results achieved when treating periodontitis sites with locally delivered doxycycline hyclate alone or scaling and root planing alone. The treatment of periodontitis sites with locally delivered doxycycline hyclate resulted in clinical improvement comparable to scaling and root planing irrespective of the patient's prophylaxis frequency.

Contemporary interpretation of probing depth assessments: diagnostic and therapeutic implications. A literature review

This paper addresses the diagnostic and therapeutic implications of increased probing depths. In general, in untreated and treated patients, when deep and shallow probing depths are compared, the data indicate that deep sites are associated with increased bleeding upon probing, elevated subgingival temperatures, higher levels of pathogens, more probing errors, a greater amount of infiltrated connective tissue, reduced ability to remove subgingival deposits with root planing, and diminished effectiveness of oral hygiene to alter the subgingival microbiota. Clinical trials demonstrate that probing depth is not a good predictor of future disease progression. However, deep sites are at greater risk of disease progression than shallow sites in untreated and treated patients. Furthermore, the deeper the probing depth, the greater the risk of future disease progression. Overall, the preponderance of evidence indicates that it is advantageous, but not always necessary, for patients to have shallow probing depths. With regards to surgical reduction of probing depths beyond that attained with non-surgical therapy, clinicians need to consider the advantages (e.g., ease of maintenance, reduced risk of disease progression) and disadvantages (e.g., root sensitivity, cosmetic defects) of treatment procedures. Since numerous variables require consideration (e.g., response to root planing, goals of therapy, acceptable level of risk for future disease progression), treatment decisions will vary depending on the patient and the desired clinical outcome at specific sites.

Short-term effects of triclosan on healing following subgingival scaling

The present clinical trial was performed to evaluate short-term effects of a triclosan-containing dentifrice/gel combination on soft tissue healing, when applied supra-/sub-gingivally at periodontal sites treated with scaling and root planing. 16 subjects with moderate periodontitis participated in a 2x 2-week, split-mouth designed clinical trial. 2 combinations of gel/dentifrice (the test combination containing triclosan) were used. 2 pairs of contralateral sites with probing pocket depth (PPD) > or 5 mm, and which bled on probing (BoP +) were selected in each patient as experimental units. A baseline examination included assessments of PPD, BoP, gingival index scores, plaque index scores, and the composition of the subgingival microbiota (dark-field microscopy). The assigned quadrant was anaesthetized and the teeth exposed to meticulous scaling and root planing. Immediately after the completion of mechanical therapy, either the test or control gel was applied subgingivally at the experimental sites. The volunteer was instructed to brush his/her teeth with an assigned dentifrice and to apply the gel (via a custom-made stent) supra-gingivally 2x daily for the following 2 weeks. He/she was recalled on day 7 for a second professional subgingival gel application. Re-examinations were carried out on days 2, 7 and 14 after treatment. 1-week wash-out periods separated the 2 experimental periods. The mean PPD reductions (between days 0 and 14) were 1.8 mm and 1.9 mm for the test and control gel/dentifrice sites. The reduction in BoP and gingival index scores was significantly greater during the test than during the control regimen. No significant differences were observed between the 2 regimens regarding plaque scores and composition of the subgingival microbiota. The findings from the present investigation demonstrated that triclosan, applied both sub- and supra-gingivally reduced soft tissue inflammation following scaling and root planing.

Microbiological response to mechanical treatment in combination with adjunctive therapy. A review of the literature

The recognition of the microbial origin and the specificity of periodontal infections has resulted in the development of several adjunctive therapies (antibiotics and/or antiseptics) to scaling and root planing in the treatment of chronic adult periodontitis. This article aims to review the "additional" effect of a subgingival irrigation with chlorhexidine, or a local or systemic application of tetracycline or metronidazole, performed in combination with a single course of scaling and root planing in patients with chronic adult periodontitis. All treatment modalities are compared with scaling and root planing, based on their impact on: the probing depth (PD); total number of colony forming units per ml (CFU/ml); the proportions and/or the detection-frequency of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia; and/or on the percentages of cocci, spirochetes, motile, and other micro-organisms on dark field microscopy examination. All treatment modalities, including scaling and root planing without additional chemical therapy, resulted in significant reductions in the probing depth and the proportions of periodontopathogens, at least during the first 8 weeks post-therapy. However in comparison to a single course of scaling and root planing, the supplementary effect of adjunctive therapies seems to be limited. In general, only the irrigation with chlorhexidine 2%, the local application of minocycline, and the systemic use of metronidazole (in case of large proportions of spirochetes) or doxycycline (in case of large proportions of A. actinomycetemcomitans) seem to result in a prolonged supplementary effect when compared to scaling and root planing. Therefore, the use of antibiotics on a routine basis, especially in a systemic way, in the treatment of chronic adult periodontitis, can no longer be advocated, considering the increasing danger for the development of microbial resistance.

Treatment of periodontal disease based on microbiological diagnosis. Relation between microbiological and clinical parameters during 5 years

The purpose of this study was to assess the clinical effect of treatment aimed to suppress Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis below detection level and Prevotella intermedia below 5% of the cultivable periodontal pocket flora. Sixteen patients and a total of 111 periodontal pockets with probing depth > or = 6 mm were included in the study. Twelve patients and a total of 77 sites completed the 5-year study. The results demonstrated clinical improvement of probing depth and gain of clinical attachment level of 3.4 mm and 1.2 mm, respectively. Treatment to eliminate indicator bacteria continued for 3 years before the aim was fulfilled. In order to eliminate A. actinomycetemcomitans from a majority of the sites, a combination of surgery and generalized tetracycline treatment was performed. A recolonization or regrowth of the indicator bacteria exceeding detection levels took place in several sites. The presence of A. actinomycetemcomitans. P. gingivalis, and P. intermedia, alone or in combination, correlated with attachment level change on the individual level. No such correlation was obtained by using presence of plaque, bleeding on probing, or three other bacteria (Campylobacter rectus, Eikenella corrodens, and Fusobacterium nucleatum) not used as treatment goal markers.

Repopulation of periodontal pockets by microbial pathogens in the absence of supportive therapy

This clinical study evaluated the reinfection incidence by Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Prevotella intermedia (Pi) in periodontal pockets following scaling and root planing (SRP) and intra-pocket irrigation with antimicrobial agents in a patient population who did not receive supportive maintenance therapy. The number of target organisms was determined utilizing DNA probes. Forty-one (41) inflamed pockets > or = 5 mm with attachment loss and containing at least one target species were selected in 6 adult patients. Following a baseline clinical and bacterial examination, all patients received thorough SRP. In addition, 1 to 2 teeth in each patient were randomly assigned to each of the following 4 treatment modalities: 1) control group, no irrigation; 2) saline group, irrigation with 2 cc of 0.85% saline; 3) tetracycline group, irrigation with 2 cc of aqueous tetracycline HCl, 50 mg/ml (5%); and 4) chlorhexidine group, irrigation with 2 cc, respectively. All selected sites were non-adjacent. No additional therapy was rendered during the entire 1-year observation period. Clinical parameters and microbial analyses were recorded again at 1 week, and 1, 3, 6, 9, and 12 months post-treatment. The effect of antimicrobial irrigation on the reinfection rate of sites by Aa, Pg, and Pi was compared with that of the control groups (1 and 2) by ANOVA. No statistically significant differences were observed among the irrigation treatment groups with regard to any of the clinical or bacterial parameters studied. Therefore, the 4 treatment groups were combined into a single group whereby the rate of bacterial repopulation following extensive scaling and root planing could be ascertained. The infection incidence of sites at baseline (of total sites), 1 week and 12 months (of sites originally infected at baseline) was 14/41, 3/14, and 7/14 for Aa; 33/41, 6/33, and 12/33 for Pg; and 37/41, 3/37, and 12/37 for Pi, respectively. Thus, half or fewer of the originally infected sites became reinfected at 12 months despite lack of maintenance therapy. The results suggest that 1) a single episode of pocket irrigation with antimicrobial agents following thorough scaling and root planing did not affect the rate of repopulation of periodontal pockets by the tested pathogens; 2) thorough scaling and root planing has a lasting suppressive effect on selected periodontal pathogens for the majority of sites in patients with adult periodontitis; 3) pre-operative probing depth, the amount of gingival fluid flow and the composition of the subgingival microflora may serve as predictors for reinfection in the absence of maintenance care; and 4) reinfection of the treated sites by Aa, Pg, and/or Pi may constitute a risk factor that diminishes the effect of therapy in the absence of supportive maintenance care.

Microbiota of rapidly progressive periodontitis lesions in association with clinical parameters

The microbial population in 73 rapidly progressive periodontitis (RPP) lesions in 10 young adults aged 25 to 35 years (5 males, 5 females) was studied in relation to the clinical parameters probing depth, bleeding on probing, and suppuration, which were recorded at the sampled sites. Porphyromonas gingivalis was found to predominate (26.7%) in 73 periodontal lesions with clinical probing depth > 6 mm, followed by Bacteroides forsythus (23.6%), and Prevotella intermedia (15.7%). The prevalence of P. gingivalis was 91.7%, Fusobacterium nucleatum, 90.4%; Streptococcus intermedius, 87.7%; and B. forsythus, 53.4%. Significant differences between bleeding index 0, 1, and 2 (P < 0.05) in frequency of detection were found for P. intermedia, Campylobacter concisus, Selenomonas sputigena, and Peptostreptococcus micros at bleeding sites and for Streptococcus sanguis, Actinobacillus actinomycetemcomitans, and B. forsythus (P < 0.001) at non-bleeding sites. Between suppurating and non-suppurating sites, significant differences (P < 0.05) in frequency of isolation were found for P. intermedia, Capnocytophaga ochracea, and A. actinomycetemcomitans at suppurating sites and for F. nucleatum at non-suppurating sites.

DNA probe analyses of the survival of selected periodontal pathogens following scaling, root planing, and intra-pocket irrigation

This clinical study evaluated the survival rates of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in periodontal pockets following scaling and root planing and intra-pocket irrigation with antimicrobial agents in patients with moderate and severe periodontitis. The number of target organisms was determined utilizing DNA probes. Adult periodontitis patients were selected on the basis that the subgingival flora contained at least one of the target organisms. Forty-eight (48) inflamed pockets > or = 5 mm in depth with probing attachment loss and containing at least one of the target species were then selected in 7 adult patients who harbored these bacteria. Following baseline clinical and bacterial examination, all patients received thorough scaling and root planing. In addition, 1 or 2 teeth in each patient which harbored the target flora at baseline were randomly assigned to each of the following 4 treatment modalities: 1) control group, no irrigation; 2) saline group, irrigation with 2 cc of physiologic saline; 3) tetracycline group, irrigation with 2 cc of aqueous tetracycline hydrochloride, 50 mg/ml (5%); and 4) chlorhexidine group, irrigation with 2 cc 0.12% chlorhexidine. All selected sites (5 to 8 per patient) were nonadjacent teeth. Clinical parameters and microbial analysis were recorded again at one week, and one month post-irrigation. The survival rate of the target microorganisms was determined and the effect of irrigation with antimicrobial agents on this microflora was compared with the control groups (1 and 2).(ABSTRACT TRUNCATED AT 250 WORDS)

The periodontally-involved root surface

Recent years have seen much research on the periodontally-involved root surface. Many of these studies have produced results which suggest that plaque contaminants of the root surface are only superficially placed, and capable of being removed by gentle means. Further research has attested to the difficulties in rendering periodontally-involved root surfaces free of calculus deposits by instrumentation, yet clinical studies show that periodontal disease can be managed by root planing. It is concluded that root surface debridement is best assessed on the basis of the healing response and that it should aim to disrupt plaque on and remove plaque from the periodontally-involved root surface rather than to remove part of the root surface itself.

Transamidase and collagenase activity in healthy and diseased human gingival tissues

Transamidases are a class of calcium-dependent mammalian enzymes which cross-link proteins by catalyzing the formation of (gamma-glutamyl)-epsilon-lysine bonds. It is possible that these enzymes play an important anabolic role in tissue healing. This study was to quantitate transamidase activity in human gingival tissue and examine the relation between transmidase activity and degree of inflammation. Forty-four out of a total 120 collected human gingival specimens from healthy and diseased patients were selected based on histometric and microbiologic criteria. Specimens were minced and homogenized in 10 mM CaCl2 and then extracted for 30 min, in 50 mM tris-HCl buffer (pH 7.5) containing 100 mM CaCl2. Following low speed centrifugation at 4 degrees C, the supernatant solution was assayed for both transamidase and collagenase activities by radioactive amine incorporation, and digestion of tritiated collagen, respectively. Appreciable levels of transamidase and collagenase activities in healthy gingivae were found. These enzyme activities were significantly elevated in the diseased and healing tissues. Unlike other transamidases, calcium was required in the enzyme extraction process.

Issues in the evaluation of clinical trials of periodontitis: a clinical perspective

The goals of clinical trials designed to establish claims for equivalency or superiority of treatment for periodontitis must be clearly stated and defined in terms of measurable and meaningful response variables. It is suggested that these clinical trials use designs that compare new treatment methods to basic periodontal therapy which consists of thorough scaling and root planing, oral hygiene instruction, and regular maintenance care. The primary response variable should be clinical attachment level. It is important to document changes in probing depth since this is a meaningful measure to many clinicians. Gingival inflammation and bleeding should be used as secondary response variables because these are not necessarily indicative of progressive periodontal destruction. Radiographic measures of disease may be useful as primary response variables if safe, reproducible and valid methods of measuring change are utilized. Microbiological monitoring should be a secondary response variable because of numerous questions concerning sampling methodology, quantitative expression of data, and meaningful interpretation in terms of relevance to disease activity. The length of periodontitis trials should be set at a minimum of 9 months if claims of superiority or equivalency are made compared to basic periodontal therapy. Calibration trials should be included and measurement error should be expressed in terms that are meaningful to the clinician while retaining statistical validity. Statistical methods for determining change should take into account site and subject heterogeneity, bursts of change and gradual change over time. It is important that statistical techniques be used that detect change as early as possible and that appropriate consideration be given to the clinical implications of the type, magnitude and duration of change in outcome variables.