Occurrence of invading bacteria in radicular dentin of periodontally diseased teeth: microbiological findings

An integrated preventive and therapeutic magnetic nanoparticle loaded with rhamnolipid and vancomycin for combating subgingival biofilms

OBJECTIVES

Mechanical debridement supplemented with antibacterial agents effectively eradicates subgingival biofilms formed in the periodontal pockets of severe periodontitis patients. However, the available antimicrobial agents have limited penetrating ability to kill the bacteria encased in the deep layers of biofilms. This study aimed to fabricate a novel magnetic nanoparticle (MNP) loaded with rhamnolipid (RL) and vancomycin (Vanc, Vanc/RL-Ag@Fe3O4) to combat subgingival biofilms.

METHODS

The multispecies subgingival biofilm was formed by periodontal pathogens, including Streptococcus oralis (S. oralis), Streptococcus sanguinis (S. sanguinis), Actinomyces naeslundii (A. naeslundii), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum). Scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the anti-biofilm efficacy of Vanc/RL-Ag@Fe3O4 with or without a magnetic field on multispecies subgingival biofilms.

RESULTS

The minimal inhibitory concentration (MIC) values of Vanc/RL-Ag@Fe3O4 on S. oralis, S. sanguinis, A. naeslundii, P. gingivalis, and F. nucleatum were 25, 50, 100, 50, and 25 μg/mL, respectively. Vanc/RL-Ag@Fe3O4 (200 μg/mL) reduced the 7-d biofilm thickness from 22 to 13 µm by degrading extracellular polymeric substance (EPS) and killing most bacteria except for tolerant F. nucleatum. A magnetic field enhanced the anti-biofilm effect of Vanc/RL-Ag@Fe3O4 by facilitating its penetration into the bottom layers of biofilms and killing tolerant F. nucleatum.

SIGNIFICANCE

Vanc/RL-Ag@Fe3O4 MNPs can release RL, Vanc, and Ag and eradicate subgingival biofilms by disrupting EPS and killing bacteria. Vanc/RL-Ag@Fe3O4 combined with a magnetic force is a promising approach for combating periodontal infection.

Clinical and microbiological efficacy of intra-pocket application of diode laser in grade C periodontitis: a randomized controlled clinical trial

BACKGROUND

Periodontitis is a microbially induced disease destroying structures anchoring teeth to jaw bones. Although metronidazole in combination with spiramycin is the effective conventional treatment of stage III grade C periodontitis, it has several systemic side effects. Laser therapy is widely used nowadays as an adjunct to scaling and root planing (SRP) to modulate inflammatory host response and eradicate microbes, due to bactericidal and detoxifying effects. Since microbiological analysis is one of the diagnostic methods identifying periodontal risk; our research aimed to investigate the efficacy of intra-pocket application of diode laser (980 nm) versus antibiotic therapy in enhancing clinical and microbiological parameters in stage III grade C periodontitis.

METHODS

A randomized controlled clinical trial was conducted on fifty patients with stage III grade C periodontitis, divided equally into two groups. We managed test group by SRP with intra-pocket application of diode laser (980 nm) and the control group by SRP with systemic antibiotic administration (spiramycin and metronidazole). Then, we measured periodontal pocket depth (PPD) and clinical attachment loss (CAL) for both groups, before treatment (baseline), four and twelve weeks after. Moreover, we collected gingival crevicular fluid from both groups at baseline, four and twelve weeks after treatment and analyzed by real-time polymerase chain reaction to detect the relative count of Aggregatibacter actinomycetemcomitans and Porhyromonas gingivalis.

RESULTS

Compared to baseline, all assessed clinical and microbiological parameters attested improvement at the end of the study period in each group individually with no significant difference between the two studied groups. Although, at twelve weeks, flare up of bacterial levels was detected with systemic antibiotic administration.

CONCLUSION

Laser therapy can be considered as an effective treatment modality in stage III grade C periodontitis, avoiding the systemic antibiotic side effects and solving the recurrence problems due to bacterial resistance by long term usage.

TRIAL REGISTRATION

NCT05222737 retrospectively on 03/02/2022, Clinicaltrial.gov.

Influence of intracanal medicaments on the periodontal and periapical healing in concurrent endodontic-periodontal lesions with/without communication: a systematic review and meta-analysis

OBJECTIVES

The purpose of this review is to determine the effectiveness of intracanal medicament (ICM) on periodontal and periapical healing (PH) of concurrent endodontic-periodontal lesions with/without communication in permanent teeth.

MATERIALS AND METHODS

The pre-defined protocol was registered in PROSPERO, and a literature search using keywords was conducted on PubMed, Scopus, Cochrane, Embase electronic databases, and Gray literature and was hand-searched until August 2023. Two reviewers independently screened the title and abstracts using the inclusion criteria. Randomized or non-randomized clinical trials, cohort studies, and case-control studies were included in the review. The same reviewers extracted the study-level data and assessed the risk of bias using the Cochrane Risk of Bias 2.0 and the Newcastle-Ottawa Scale (NOS) independently. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to assess the certainty of evidence. Random effects meta-analysis was performed on eligible studies using Revman software.

RESULTS

A total of 598 records were identified from the database search; seven studies met the inclusion criteria and were included in the review. Four randomized clinical trials, two prospective cohorts, and one retrospective case-control study with 362 patients were included. Calcium hydroxide (CH) was the most commonly used ICM, followed by using chlorhexidine gel in four studies. Periodontal therapy was performed as initial scaling and root planning (SRP) in all studies, along with open flap debridement (OFD) in three randomized clinical trials. The time lapse between two treatment protocols was variable (ranging from 1 week to 3 months). All studies exhibited a decrease in probing depth (PD) and an increase in clinical attachment level (CAL) after the treatment. Meta-analysis showed insignificant differences between different ICM materials, and the certainty of evidence was low.

CONCLUSION

In patients with/without concurrent endodontic-periodontal lesions, intracanal medication improved clinical periodontal parameters following endodontic therapy. In terms of influence on periapical healing, the results were inconclusive.

CLINICAL RELEVANCE

Two-visit RCT may be considered since it allows for the placement of an ICM in endodontic-periodontal lesions with/without communication. Sufficient time should be allowed after endodontic therapy for any potential periodontal regeneration to occur.

Cemental tear: Literature review, proposed classification and recommendations for treatment

Cemental tears are an important condition of relevance to Endodontics but are often overlooked. A cemental tear is the partial or complete detachment of the cementum from the cemento-dentinal junction or along the incremental line within the body of cementum. The limited attention received is most likely due to the limited awareness amongst dental professionals and challenges in accurately diagnosing them, resulting in misdiagnosis and erroneous treatment. The aim of this review is to describe the: (i) epidemiology and predisposing factors; (ii) clinical, radiographic and histological features and (iii) the clinical management and treatment outcomes of cemental tear. The review included 37 articles published in English that comprised eight observational studies and 29 case reports. The prevalence of cemental tears was reported to be lower than 2%; whilst the incidence remains unknown. Internal factors due to the inherent structural weakness of cementum and its interface with the dentine, and external factors that are associated with stress have been proposed as the two mechanisms responsible for the development and propagation of cemental tears. Predisposing factors that have been implicated were tooth type, gender, age, previous root canal treatment, history of dental trauma, occlusal trauma and excessive occlusal force; however, evidence is limited. Common clinical and radiographic manifestations of cemental tears resemble the presentations of primary endodontic diseases, primary periodontal diseases and combined endodontic-periodontal lesions. Clinical management tended to focus on complete removal of the torn fragments and periodontal treatment, often combined with regenerative treatment. In this article, a new classification for cemental tears is developed that consists of classes 0 to 6 and stages A, B, C and D based on the: (i) location and accessibility of the torn cemental fragment; (ii) the pattern and extension of the associated bony defect in relation to the root length and (iii) the number of root surface/s affected by the cemental tear/s and the associated bony defect. Recommendations for treatment strategies are also provided and linked to the classification to aid in streamlining the process of treatment decision making.

A re-evaluation of scaling and root planing

BACKGROUND

Extensive reviews on the role of scaling and root planing (SRP) in the treatment of periodontitis have been previously published. This commentary will address the importance of subgingival calculus in the progression and treatment of periodontitis and addresses factors that make the execution of a "definitive" SRP a critical part of therapy.

METHODS

A search for articles, using keywords relevant to the subject , (e.g., periodontitis, dental scaling, root planing, dental calculus, biofilm, inflammation) was conducted using PubMed, Ovid Medline, Cochrane Reviews and the ADA Center for Evidence Based Dentistry data bases. Additionally, references cited in relevant articles were also considered.

RESULTS

Surfaces of subgingival calculus are covered with a biofilm of metabolically active bacteria. Periodontal inflammation is clearly related to the presence of calculus and biofilm. The primary goal of SRP is removal of subgingival calculus and biofilm deposits to create a biologically compatible root surface and reduce the inflammatory burden. Current evidence suggests that inflammation associated with periodontal infections affects both the immediate oral environment and the patient's systemic health.

CONCLUSION

SRP is still critical to the treatment of periodontitis. SRP involving deep probing depths (≥ 5 mm) and root surfaces with anatomical and surface irregularities, regardless of the type of instrumentation, requires time, exceptional skill and perseverance, and patient compliance with periodontal maintenance. Sites with persistent nonresponding probing depths and signs of inflammation following a definitive SRP, should be considered for surgical intervention.

Applying nano-HA in addition to scaling and root planing increases clinical attachment gain

Purpose

This study evaluated the efficacy of treating periodontitis using subgingival nano-hydroxyapatite powder with an air abrasion device (NHAPA) combined with scaling and root planing (SRP).

Methods

A total of 28 patients with stage III periodontitis (grade B) were included in this study, although 1 was lost during follow-up and 3 used antibiotics. The patients were divided into a test group and a control group. All patients first received whole-mouth SRP using hand instruments, and a split-mouth approach was used for the second treatment. In the test group, the teeth were treated with NHAPA for 15 seconds at 70% power per pocket. Subgingival plaque samples were obtained from the 2 deepest pockets at the test and control sites before treatment (baseline) and 3 months after treatment. The full-mouth plaque index (PI), gingival index (GI), papillary bleeding index (PBI), bleeding on probing (BOP), probing depth (PD) and clinical attachment level (CAL) were recorded at baseline and at 1- and 3-month post-treatment. Real-time polymerase chain reaction was used to determine the colonisation of Treponema denticola (Td), Porphyromonas gingivalis (Pg), and Aggregatibacter actinomycetemcomitans in the subgingival plaque.

Results

From baseline to the first month, the test group showed significantly larger changes in BOP and CAL (43.705%±27.495% and 1.160±0.747 mm, respectively) than the control group (36.311%±27.599% and 0.947±0.635 mm, respectively). Periodontal parameters had improved in both groups at 3 months. The reductions of PI, GI, BOP, PD, and CAL in the test group at 3 months were greater and statistically significant. The total bacterial count and Td and Pg species had decreased significantly by the third month in both groups (P<0.05).

Conclusions

Applying NHAPA in addition to SRP improves clinical periodontal parameters more than SRP alone. Subgingival NHAPA may encourage clot adhesion to tooth surfaces by increasing surface wettability.

Evaluation of efficacy of non-thermal atmospheric pressure plasma in treatment of periodontitis: a randomized controlled clinical trial

OBJECTIVES

In this clinical study, we aim to evaluate the effectiveness of non-thermal atmospheric pressure plasma (NAPP), which is a novel procedure used in periodontal pocket decontamination adjunctive to non-surgical periodontal treatment (NSPT).

METHODS

The study included 25 systemically healthy periodontitis patients. In the split-mouth design, NAPP application into the pockets, in addition to NSPT, was performed. Clinical periodontal data, gingival crevicular fluid, and subgingival plaque samples of patients were taken before and during the first and third months of treatment. Biochemical assays were conducted using enzyme-linked immunosorbent assay. Analysis of bacteria was performed with polymerase chain reaction method.

RESULTS

There was more clinical attachment level (CAL) gain in the 3rd month in the test group (deep pockets: 3.90 mm, pockets ≥ 5 mm: 2.72 mm) compared to the control group (deep pockets: 3.40 mm, pockets ≥ 5 mm: 2.58 mm) (p < 0.05), but no significant difference between groups in CAL. Clinical periodontal parameters improved in both study groups (p < 0.05). However, the gingival index (GI) and the bleeding on probing (BOP) rate decreased more in the test group (GI: 0.55, BOP: 9.48%, and GI: 0.38, BOP: 8.46% in the 1st and 3rd months, respectively) compared to the control group (GI: 0.68, BOP: 13.43%, and GI: 0.52, BOP: 14.58%) (p < 0.05). In addition, there was no significant difference in probing depth and biochemical markers between groups (p > 0.05). It was observed that NAPP reduced the number of bacteria more than the control group in the 1st and 3rd months.

CONCLUSIONS

It was seen that the single-time NAPP application concurrent with NSPT provided additional CAL gain, elimination of putative periodontopathogens and reduced their recolonization. Longitudinal studies with larger population and longer time are required.

CLINICAL RELEVANCE

NSPT is an effective method for the treatment of periodontitis but bacteria recolonization that causes recurrence of the periodontal disease occurs within a short period. NAPP can reduce the recurrence of periodontal disease by providing better bacterial elimination and should, therefore, be used in maintenance of periodontitis.

[Time lapse between endodontic and periodontal treatments of combined periodontal-endodontic lesion: a systematic review]

OBJECTIVE

This study aims to evaluate the time lapse between the endodontic and periodontal treatments of the combined periodontal-endodontic lesion to guide the clinical treatment.

METHODS

A systemic literature search was performed in articles published from 1980 to March 2017 using the electronic databases, including PubMed, EMbase, Cochrane, Web of Science, CNKI, CBM, and Wanfang Databases.

RESULTS

After screening, two randomized controlled trials, two prospective case series studies, and eight case reports were ultimately included. All clinical studies and case reports were treated with root canal therapy and periodontal nonsurgical or periodontal surgical treatment, with root canal therapy as the initial treatment step. Changes in the periodontal probing depth and attachment loss were reported in all clinical studies and case reports.

CONCLUSIONS

An observational period between the endodontic and periodontal nonsurgical treatments may not be required. However, given that the quality of several included studies was limited, and the number of randomized controlled trials was small, a large number of randomized controlled trials are needed to verify this result.

Septic arthritis of knee joint due to Parvimonas micra

Parvimonas species are anaerobic, Gram-positive cocci that are a constituent of normal oral and gastrointestinal flora. We present a case of right knee joint septic arthritis due to Parvimonas micra in an immunocompromised patient. A 61-year-old male renal and pancreatic transplant recipient on immunosuppressive therapy was admitted to our hospital due to intense pain, joint swelling and inability to move his right knee over the past 9 months. After synovial fluid was drawn, cultures were positive for P. micra, an anaerobic pathogen that is part of the flora of the oral cavity. We report a rare causative pathogen for septic arthritis in an immunocompromised patient.

Selective photoantisepsis

BACKGROUND AND OBJECTIVE

Selective killing of pathogens by laser is possible due to the difference in absorption of photon energy by pathogens and host tissues. The optical properties of pathogenic microorganisms are used along with the known optical properties of soft tissues in calculations of the laser-induced thermal response of pathogen colonies embedded in a tissue model. The objective is to define the laser parameters that optimize pathogen destruction and depth of the bactericidal effect.

MATERIALS AND METHODS

The virtual periodontium is a computational model of the optical and time-dependent thermal properties of infected periodontal tissues. The model simulates the periodontal procedure: Laser Sulcular Debridement.¹ Virtual pathogen colonies are placed at different depths in the virtual periodontium to determine the depth for effective bactericidal effects given various laser parameters (wavelength, peak power, pulse duration, scan rate, fluence rate) and differences in pathogen sensitivities.

RESULTS

Accumulated background heat from multiple passes increases the depth of the bactericidal effect. In visible and near-IR wavelengths the large difference in absorption between normal soft tissue and Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) results in selective destruction. Diode laser (810 nm) efficacy and depth of the bactericidal effect are variable and dependent on hemin availability. Both pulsed-Nd:YAG and the 810 nm diode lasers achieve a 2-3 mm deep damage zone for pigmented Pg and Pi in soft tissue without surface damage (selective photoantisepsis). The model predicts no selectivity for the Er:YAG laser (2,940 nm). Depth of the bactericidal effect is highly dependent on pathogen absorption coefficient. Highly sensitive pathogens may be destroyed as deep as 5-6 mm in soft tissue. Short pulse durations enable confinement of the thermal event to the target. Temporal selectivity is achieved by adjusting pulse duration based on target size.

CONCLUSION

The scatter-limited phototherapy model of the infected periodontium is applied to develop a proper dosimetry for selective photoantisepsis. Dosimetry planning is essential to the development of a new treatment modality. Lasers Surg. Med. 48:763-773, 2016. © 2016 Wiley Periodicals, Inc.

An endodontic conundrum: the association between pulpal infection and periodontal disease

This paper reviews the classification of periodontal-endodontic lesions and considers the pathways through which inflammatory lesions or bacteria may communicate between the pulp and the periodontium. Such communications have previously underpinned the classification of periodontal-endodontic lesions but a more up-to-date approach is to focus specifically on those lesions that originate concurrently as pulpal infection (and necrosis) and periodontal disease on the affected teeth. In doing so, both conventional periodontal and endodontic treatments are indicated for the affected teeth, although more complex management strategies may occasionally be indicated.

Adjunctive Application of Antimicrobial Photodynamic Therapy in Nonsurgical Periodontal Treatment: A Review of Literature

Periodontal disease is caused by dental plaque biofilms, and the removal of these biofilms from the root surface of teeth plays a central part in its treatment. The conventional treatment for periodontal disease fails to remove periodontal infection in a subset of cases, such as those with complicated root morphology. Adjunctive antimicrobial photodynamic therapy (aPDT) has been proposed as an additional treatment for this infectious disease. Many periodontal pathogenic bacteria are susceptible to low-power lasers in the presence of dyes, such as methylene blue, toluidine blue O, malachite green, and indocyanine green. aPDT uses these light-activated photosensitizer that is incorporated selectively by bacteria and absorbs a low-power laser/light with an appropriate wavelength to induce singlet oxygen and free radicals, which are toxic to bacteria. While this technique has been evaluated by many clinical studies, some systematic reviews and meta-analyses have reported controversial results about the benefits of aPDT for periodontal treatment. In the light of these previous reports, the aim of this review is to provide comprehensive information about aPDT and help extend knowledge of advanced laser therapy.

Effect of Time Lapse between Endodontic and Periodontal Therapies on the Healing of Concurrent Endodontic-Periodontal Lesions without Communication: A Prospective Randomized Clinical Trial

INTRODUCTION

The aim of this prospective randomized clinical trial was to evaluate the effect of a time lapse between endodontic treatment and nonsurgical periodontal treatment on periodontal healing of concurrent endodontic-periodontal lesions without communication.

METHODS

Thirty-one patients were randomly divided into 2 groups: group 1: endodontic treatment and scaling and root planning (SRP) were performed simultaneously and group 2: SRP was performed 3 months after endodontic treatment. Both groups were followed for 3 and 6 months after SRP. Primary outcome variables were the probing depth, clinical attachment level, and periapical index score.

RESULTS

Both the groups showed a significant improvement in all the clinical parameters evaluated after the completion of endodontic and periodontal treatment (P < .05). No statistically significant difference in improvement was observed between the 2 groups at 3 and 6 months after SRP (P > .05). Periodontal healing responses were comparable in the 2 groups, with no apparent detriment resulting from simultaneous treatment. Improvements in periodontal parameters that were achieved in 6 months in group 2 were achieved only in 3 months in group 1 (P > .05).

CONCLUSIONS

Nonsurgical periodontal treatment may be performed simultaneously with endodontic treatment in the management of concurrent endodontic-periodontal lesions without communication, and an observation period after endodontic treatment may not be required.

Antimicrobial activity of platelet-rich plasma and other plasma preparations against periodontal pathogens

BACKGROUND

In addition to releasing a pool of growth factors during activation, platelets have many features that indicate their role in the anti-infective host defense. The antimicrobial activities of platelet-rich plasma (PRP) and related plasma preparations against periodontal disease-associated bacteria were evaluated.

METHODS

Four distinct plasma fractions were extracted in the formulation used commonly in dentistry and were tested for their antibacterial properties against three periodontal bacteria: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum. The minimum inhibitory concentration of each plasma preparation was determined, and in vitro time-kill assays were used to detect their abilities to inhibit bacterial growth. Bacterial adhesion interference and the susceptibility of bacterial adherence by these plasma preparations were also conducted.

RESULTS

All plasma preparations can inhibit bacterial growth, with PRP showing the superior activity. Bacterial growth inhibition by PRP occurred in the first 24 hours after application in the time-kill assay. PRP interfered with P. gingivalis and A. actinomycetemcomitans attachment and enhanced exfoliation of attached P. gingivalis but had no influences on F. nucleatum bacterial adherence.

CONCLUSIONS

PRP expressed antibacterial properties, which may be attributed to platelets possessing additional antimicrobial molecules. The application of PRP on periodontal surgical sites is advisable because of its regenerative potential and its antibacterial effects.

Evaluation of efficacy of chlorhexidine intracanal medicament on the periodontal healing of concomitant endodontic-periodontal lesions without communication: an interventional study

BACKGROUND

Treatment of concomitant endodontic-periodontal lesions remains a challenge in clinical practice and requires effective endodontic and regenerative periodontal therapy. Among other factors, cross seeding and recolonization of flora may affect the outcome of periodontal therapy. Intracanal medicaments have been shown to exert antimicrobial activity on the external root surface, and local delivery of antimicrobials has been suggested to be a complementary approach in the management of periodontitis. Therefore, the objective of this study is to determine the influence of chlorhexidine (CHX) intracanal medicament on the clinical outcomes of therapy.

METHODS

Thirty-one patients were divided into two treatment groups: 1) open flap debridement (OFD) in endodontically treated teeth (control); and 2) OFD in endodontically treated teeth with CHX placed in the coronal space (test). The clinical variables evaluated were probing depth (PD), clinical attachment level (CAL), and percentage of sites with PD ≥5 mm. Reevaluation was performed at 3 and 6 months post-surgery.

RESULTS

Both treatments resulted in improvement in all the clinical variables evaluated. Postoperative measurements from test and control groups showed reductions in mean PD of 2.22 ± 1.27 and 0.91 ± 0.81 mm, mean CAL gains of 2.16 ± 1.12 and 0.60 ± 0.93 mm, and 43.33% ± 31.37% and 17.71% ± 14.23% reduction in sites with PD ≥5 mm. Significantly more PD reduction, CAL gain, and percentage reduction in sites with PD ≥5 mm were observed in the test group at 6 months (P <0.05).

CONCLUSION

CHX may be used as an effective intracanal medicament for promoting periodontal healing in concomitant endodontic-periodontal lesions.

Influence of endodontic treatment on systemic oxidative stress

INTRODUCTION

An increased production of oxidizing species related to reactive oral diseases, such as chronic apical periodontitis, could have systemic implications such as an increase in cardiovascular morbidity. Based on this consideration, we conducted a prospective study to assess whether subjects affected by chronic periodontitis presented with higher values of oxidative stress than reference values before endodontic treatment, and whether endodontic treatment can reduce the oxidative imbalance and bring it back to normal in these subjects.

MATERIALS AND METHODS

The authors recruited 2 groups of patients from private studies and dental clinics: these patients were recruited randomly. The oxidative balance in both patients with chronic apical periodontitis (CAP) and healthy control patients was determined by measuring the oxidant status, using an identification of the reactive oxygen metabolites (d-ROMs) test, while the antioxidant status in these patients was determined using a biological antioxidant potential (BAP) test. Both these tests were carried on plasma samples taken from enrolled patients. Values were measured both before the endodontic treatment of the patients with chronic apical periodontitis, and 30 and 90 days after treatment, and compared to those obtained from healthy control patients.

RESULTS

It was found that, on recruitment, the patients with chronic apical periodontitis exhibited significantly higher levels of oxidative stress than control patients, as determined by the d-ROMs and BAP tests. Furthermore, the d-ROMs test values were shown to decrease and the BAP test values to increase over time in patients with chronic apical periodontitis following endodontic therapy. As the levels of oxidative stress in these patients tended to reduce and return to normal by 90 days following treatment.

CONCLUSIONS

This study has demonstrated a positive association between chronic apical periodontitis and oxidative stress. Subjects affected by chronic apical periodontitis are exposed to a condition of oxidative stress, which is extremely dangerous to general health. Moreover, one can infer from these findings that through proper endodontic therapy, a good oxidative balance can be restored, thereby avoiding the risk of contracting the abovementioned diseases.

Histopathological features of dental pulp in teeth with different levels of chronic periodontitis severity

Purpose. To evaluate the histopathological condition of the pulp in teeth with different levels of chronic periodontitis in humans. Methods. Twenty-five single-root nondecayed teeth were divided into three groups as follows: group 1, clinical attachment level (CAL) 3 to 4 mm and alveolar bone loss (BL) from 4 to 6 mm without reaching the tooth apex; group 2, CAL ≥ 5 mm and BL > 6 mm without reaching the tooth apex; group 3, CAL ≥ 5 mm and BL > 6 mm up to the tooth apex. Histological analyses were accomplished after laboratorial processing. Results. The mean of CAL was 3.2 ± 0.7 mm in group 1, 7.6 ± 2.0 mm in group 2, and 12.1 ± 2.8 mm in group 3, while for BL it was 4.8 ± 0.9 mm, 7.6 ± 2.2 mm, and 11.9 ± 2.1 mm, respectively. Histopathological data in the pulpal chambers were similar among the three groups showing normal aspects, and, the radicular pulps showed variable levels of reactive dentin, fibrosis, dystrophic mineralizations, atrophy, and mononuclear inflammatory infiltrate. Conclusions. Gradual progression of the chronic periodontitis led to changes in the histopathological aspects of the radicular pulp with progressive involvement.

In vitro adhesion of Streptococcus sanguinis to dentine root surface after treatment with Er:YAG laser, ultrasonic system, or manual curette

OBJECTIVE

The purpose of this in vitro study was to evaluate the dentine root surface roughness and the adherence of Streptococcus sanguinis (ATCC 10556) after treatment with an ultrasonic system, Er:YAG laser, or manual curette.

BACKGROUND DATA

Bacterial adhesion and formation of dental biofilm after scaling and root planing may be a challenge to the long-term stability of periodontal therapy.

MATERIALS AND METHODS

Forty flattened bovine roots were randomly assigned to one of the following groups: ultrasonic system (n = 10); Er:YAG laser (n = 10); manual curette (n = 10); or control untreated roots (n = 10). The mean surface roughness (Ra, microm) of the specimens before and after exposure to each treatment was determined using a surface profilometer. In addition, S. sanguinis was grown on the treated and untreated specimens and the amounts of retained bacteria on the surfaces were measured by culture method.

RESULTS

All treatments increased the Ra; however, the roughest surface was produced by the curettes. In addition, the specimens treated with curettes showed the highest S. sanguinis adhesion. There was a significant positive correlation between roughness values and bacterial cells counts.

CONCLUSION

S. sanguinis adhesion was the highest on the curette-treated dentine root surfaces, which also presented the greatest surface roughness.

Presence of bacteria in dentinal tubules

This study demonstrated that a significant number of bacteria is present in the radicular dentinal tubules of periodontally diseased human teeth. Ten periodontally diseased teeth were prepared and stained by Brown and Brenn technique for histological examination. Bacteria were detected in all teeth. It is suggested that bacteria may invade dentinal tubules exposed to periodontal pocket and are very hard to be eliminated by conventional mechanical and chemical periodontal therapy. Contaminated dentinal tubules of periodontally diseased teeth can thus act as active bacterial reservoirs to promote recolonization of mechanically treated root surfaces, which could interfere with the periodontal healing and progression of the disease.

Risk ofPorphyromonas gingivalisRecolonization During the Early Period of Periodontal Maintenance in Initially Severe Periodontitis Sites

BACKGROUND

Porphyromonas gingivalis is considered a critical pathogen of periodontal diseases including recurrent periodontitis. The profound effects of active periodontal treatment (APT) on P. gingivalis elimination were previously demonstrated and revealed that the subsequent P. gingivalis-free or -suppressed status seems to be maintained during early periodontal maintenance (PMT). The aim of the present study was to show the occurrence of microbial recolonization during this early PMT period.

METHODS

In total, 128 sites from 11 generalized chronic periodontitis patients and one generalized aggressive periodontitis patient underwent clinical and microbiologic examination at baseline (Exam-I), after APT (Exam-II), and in PMT (Exam-III). Exam-III was carried out an average of 4.5 +/- 3.5 months after Exam-II. Detection and quantification of putative pathogens were performed using a polymerase chain reaction-based method.

RESULTS

The PMT used was effective in maintaining the clinical conditions improved by APT. However, in microbiological examinations, Exam-III showed higher detection frequency and levels of P. gingivalis than Exam-II. This suggests that a P. gingivalis recolonization started in the early PMT period. P. gingivalis-increased sites then showed significantly more severe signs of periodontitis in Exam-I than P. gingivalis-stable sites (bleeding on probing frequency: 76.7% versus 56.5%; suppuration frequency: 41.9% versus 12.9%). On the other hand, in Exam-II, no significant differences of clinical parameters were noted between P. gingivalis-increased and -stable sites.

CONCLUSION

Severe periodontitis sites before APT seemed to place them at risk of P. gingivalis recolonization in the early PMT period, and this microbial restoration could be a cause of recurrent periodontitis.

Longitudinal Clinical Evaluation of Adjunct Minocycline in the Treatment of Chronic Periodontitis

BACKGROUND

The clinical benefits of minocycline in combination with thorough scaling and root planing (SRP) have been examined in multicenter studies. The aim of this longitudinal investigation was to evaluate the clinical response to scaling and root planing combined with the use of locally delivered minocycline microspheres for 720 days in individuals with advanced chronic periodontitis.

METHODS

A total of 26 individuals aged 26 to 69 years (mean: 46.8+/-12.1 years) were included in this double-blind randomized clinical trial. After randomization, 13 individuals were selected for the test group (TG) and treated with SRP plus subgingival minocycline at baseline and 90, 180, and 270 days, and 13 individuals were selected for the control group (CG) and received SRP plus vehicle at the same timepoints. Two homologous sites with probing depth (PD)>or=6 mm were chosen in each subject. To evaluate the clinical response after treatment, PD, plaque index (PI), and gingival index (GI) were assessed at baseline and 90, 180, 270, 360, and 720 days.

RESULTS

No statistical differences were found between test and control groups in relation to PD at the different timepoints. The mean values of PD demonstrated a higher reduction in the test group at 270 and 360 days. No statistical differences were observed at 90, 180, and 720 days between TG and CG (P<0.05; Wilcoxon test). There were no statistically significant differences between TG and CG concerning PI and GI (P<0.05; analysis of variance and t test) at all evaluated timepoints.

CONCLUSION

Our findings demonstrated that both therapies reduced mean PD from 90 to 360 days; however, SRP combined with the use of subgingival minocycline showed a higher reduction at 270 and 360 days following therapy.

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.

Clinical and microbial evaluation of dental scaling associated with subgingival minocycline in chronic periodontitis subjects

The aims of this double-blind randomized clinical trial were to evaluate the presence of periodontal pathogens and the clinical response of periodontal pockets treatment to scaling and root planing (SRP) associated with subgingival minocycline (SM). A total of 36 subjects, 26 to 60 years old (40.7 ± 9.1), who had been previously diagnosed with chronic periodontitis, were included in the present study. Eighteen subjects were selected for the test group (TG), who were treated with SRP plus SM (new treatment), and 18 subjects for the control group (CG) who received SRP plus vehicle (current treatment). Two homologous sites in each subject with a probing depth (PD) > 6 mm were chosen. To evaluate the clinical response after treatment, PD was measured at baseline and at 90 days. Microbiological evaluation was performed to detect 7 periodontal pathogens using polymerase chain reaction at baseline, 30, and 120 days. A mean reduction in PD of 2.8 and 2.1 mm was observed in the TG and CG, respectively. At baseline, P. gingivalis was the most prevalent organism in both test (65.8%) and control (48.6%) groups. After 120 days it fell to 30.8% in TG and to 23.1% in CG. There were no statistically significant differences between the test and control groups concerning PD (p > 0.05 by Wilcoxon test) or presence of periodontal pathogens (p > 0.05 by Wilcoxon and chi-square; p > 0.01 by Signal test). The results observed showed that the new treatment was as effective as the current treatment in reducing periodontal pathogens and PD among chronic periodontitis subjects.

Invasion of dentinal tubules by oral bacteria

Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.

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.

Nonsurgical periodontal therapy

Regular home care by the patient in addition to professional removal of subgingival plaque is generally very effective in controlling most inflammatory periodontal diseases. When disease does recur, despite frequent recall, it can usually be attributed to lack of sufficient supragingival and subgingival plaque control or to other risk factors that influence host response, such as diabetes or smoking. Causative factors contributing to recurrent disease include deep inaccessible pockets, overhangs, poor crown margins and plaque-retentive calculus. In most cases, simply performing a thorough periodontal debridement under local anesthesia will stop disease progression and result in improvement in the clinical signs and symptoms of active disease. If however, clinical signs of disease activity persist following thorough mechanical therapy, such as increased pocket depths, loss of attachment and bleeding on probing, other pharmacotherapeutic therapies should be considered. Augmenting scaling and root planing or maintenance visits with adjunctive chemotherapeutic agents for controlling plaque and gingivitis could be as simple as placing the patient on an antimicrobial mouthrinse and/or toothpaste with agents such as fluorides, chlorhexidine or triclosan, to name a few. Since supragingival plaque reappears within hours or days after its removal, it is important that patients have access to effective alternative chemotherapeutic products that could help them achieve adequate supragingival plaque control. Recent studies, for example, have documented the positive effect of triclosan toothpaste on the long-term maintenance of both gingivitis and periodontitis patients. Daily irrigation with a powered irrigation device, with or without an antimicrobial agent, is also useful for decreasing the inflammation associated with gingivitis and periodontitis. Clinically significant changes in probing depths and attachment levels are not usually expected with irrigation alone. Recent reports, however, would indicate that, when daily irrigation with water was added to a regular oral hygiene home regimen, a significant reduction in probing depth, bleeding on probing and Gingival Index was observed. A significant reduction in cytokine levels (interleukin-1beta and prostaglandin E2, which are associated with destructive changes in inflamed tissues and bone resorption also occurs. If patient-applied antimicrobial therapy is insufficient in preventing, arresting, or reversing the disease progression, then professionally applied antimicrobial agents should be considered including sustained local drug delivery products. Other, more broadly based pharmacotherapeutic agents may be indicated for multiple failing sites. Such agents would include systemic antibiotics or host modulating drugs used in conjunction with periodontal debridement. More aggressive types of juvenile periodontitis or severe rapidly advancing adult periodontitis usually require a combination of surgical intervention in conjunction with systemic antibiotics and generally are not controlled with nonsurgical anti-infective therapy alone. It should be noted, however, that, to date, no home care products or devices currently available can completely control or eliminate the pathogenic plaques associated with periodontal diseases for extended periods of time. Daily home care and frequent recall are still paramount for long-term success. Nonsurgical therapy remains the cornerstone of periodontal treatment. Attention to detail, patient compliance and proper selection of adjunctive antimicrobial agents for sustained plaque control are important elements in achieving successful long-term results. Frequent re-evaluation and careful monitoring allows the practitioner the opportunity to intervene early in the disease state, to reverse or arrest the progression of periodontal disease with meticulous nonsurgical anti-infective therapy.

Bacterial adhesins--their role in tubule invasion and endodontic disease

Bacterial invasion of dentinal tubules is critical to the progression of dental caries and the development of pulp and periapical disease, and may also influence the progression of periodontal disease. However, little is known about the host or bacterial mechanisms involved in tubule invasion. Recent work has demonstrated that bacterial interactions with dentine, and salivary and tissue molecules influence invasion. Salivary molecules such as mucin and immunoglobulin G (IgG) co-aggregate with bacterial cells, which inhibits dentine invasion, while deposition of dentinal tubule fluid molecules e.g. albumin, IgG, or fibrinogen within dentinal tubules also inhibits invasion. Dentine invasion by streptococci has been shown to be associated with a bacterial growth response and adhesion to unmineralized collagen, which are mediated by streptococcal cell-surface antigen I/II polypeptides. These adhesins possess diverse binding properties including binding to salivary glycoprotein, other bacteria, and to collagen. Additionally, some antigen I/II polypeptides facilitate species-specific co-invasion between streptococci and obligate anaerobes that lack the ability to invade by themselves. An understanding of the mechanisms involved in bacterial invasion of dentine should allow development of new control strategies.

Study of dentinal tubule architecture of permanent upper premolars: evaluation by SEM

Dentinal tubules are the means by which the pulp and mineralised tissues surrounding the dentine (enamel and cementum) communicate. Through these tubules external agents can damage the pulp and subsequently the periodontal ligament. Given the importance of dentinal tubules, the authors evaluated the numerical density, shape, and individual surface area of tubule openings and the percentage of dentine occupied by these. Eight permanent upper premolars were studied using scanning electron microscopy (SEM). In the crown, the external surface of the dentine was evaluated at the dentino-enamel junction and the internal surface at the pulp chamber wall. At the cervical, middle and apical thirds of the root, the external surface was evaluated at the cemento-dentinal junction and the internal surface at the root canal wall. The results showed that numerical density of tubule openings is significantly greater (p < 0.05) at the cervical third of the dentine, at its junction with the cementum and at the pulpal chamber wall, with respect to other areas evaluated. The individual surface area of each opening varied from 5.72 microns 2 in the dentine of the pulpal chamber wall to 0.97 micron 2 in the dentine of the apical third of the root canal wall. The percentage of area occupied by the dentinal tubules per mm2 of dentine was significantly higher (p < 0.01) at the internal dentinal surface as compared to the external. The shape of the tubule openings was found to be circular in the crown and became more irregular as the apical third of the root was approached.

Viable bacteria in root dentinal tubules of teeth with apical periodontitis

Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight teeth was examined histologically. Using the culturing technique bacteria were found in 77% of the dentin samples from set 1 (Amsterdam) and in 87.5% of the dentin samples from set 2 (Glasgow). At greater distance, in layer C, from the pulp bacteria were found in 62% (13 of 21) of the dentin samples. Twenty-three percent (3 of 13) of set 1 and 25% (2 of 8) of set 2 contained >50,000 colony-forming units/mg of dentin in layer C. In layers closer to the pulp higher numbers of anaerobic bacteria and gram-positive rods were found, as well as a larger number of bacterial species. Histological sections showed bacterial penetration in dentinal tubules in 5 of 8 teeth. In the other three teeth where the colony-forming units/mg recovered was <10,000, no histological signs of tubule penetration was seen. It seems clear that, in more than half of the infected roots, bacteria are present in the deep dentin close to the cementum and that anaerobic culturing of dentin is more sensitive than histology to detect these bacteria.

Interactions between periodontal bacteria and human oral epithelial cells: Fusobacterium nucleatum adheres to and invades epithelial cells

Bacteria are causative agents of periodontal diseases. Interactions between oral bacteria and gingival epithelial cells are essential aspects of periodontal infections. Using an in vitro tissue culture model, a selected group of gram-negative anaerobic bacteria frequently associated with periodontal diseases, including Bacteroides forsythus, Campylobacter curvus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia, were examined for their ability to adhere to and invade primary cultures of human gingival epithelial cells (HGEC). The effects of these bacteria on the production of interleukin-8 (IL-8), a proinflammatory chemokine, were also measured. These studies provided an initial demonstration that F. nucleatum adhered to and invaded HGEC and that this was accompanied by high levels of IL-8 secretion from the epithelial cells. The attachment and invasion characteristics of F. nucleatum were also tested using KB cells, an oral epithelial cell line. The invasion was verified by transmission electron microscopy and with metabolic inhibitors. Invasion appeared to occur via a "zipping" mechanism and required the involvement of actins, microtubules, signal transduction, protein synthesis, and energy metabolism of the epithelial cell, as well as protein synthesis by F. nucleatum. A spontaneous mutant, lam, of F. nucleatum, isolated as defective in autoagglutination, was unable to attach to or invade HGEC or KB cells, further indicating the requirement of bacterial components in these processes. Sugar inhibition assays indicated that lectin-like interactions were involved in the attachment of F. nucleatum to KB cells. Investigation of these new virulence phenotypes should improve our understanding of the role of F. nucleatum in periodontal infections.

Destructive knee joint infection caused by Peptostreptococcus micros: importance of early microbiological diagnosis

Peptostreptococcus micros is a commensal of the oral cavity and the genitourinary tract that rarely causes serious infections. A case of a destructive knee joint infection with rapid progress caused by P. micros is presented. The significance of the microbiological findings was initially not acknowledged, which contributed to a nonsuccessful clinical outcome.