Efficacy of subgingivally applied minocycline in the treatment of chronic periodontitis

Near-infrared light-boosted antimicrobial activity of minocycline/hyaluronan/carbon nanohorn composite toward peri-implantitis treatments

Dental implant therapy is a reliable treatment for replacing missing teeth. However, as dental implants become more widely used, peri-implantitis increasingly has become a severe complication, making successful treatment more difficult. As a result, the development of effective drug delivery systems (DDSs) and treatments for peri-implantitis are urgently needed. Carbon nanohorns (CNHs) are carbon nanomaterials that have shown promise for use in DDSs and have photothermal effects. The present study exploited the unique properties of CNHs to develop a phototherapy employing a near-infrared (NIR) photoresponsive composite of minocycline, hyaluronan, and CNH (MC/HA/CNH) for peri-implantitis treatments. MC/HA/CNH demonstrated antibacterial effects that were potentiated by NIR-light irradiation, a property that was mediated by photothermal-mediated drug release from HA/CNH. These antibacterial effects persisted even following 48 h of dialysis, a promising indication for the clinical use of this material. We propose that the treatment of peri-implantitis using NIR and MC/HA/CNH, in combination with surgical procedures, might be employed to target relatively deep affected areas in a timely and efficacious manner. We envision that this innovative approach will pave the way for future developments in implant therapy.

Effect of Locally Delivered Minocycline on the Profile of Subgingival Bacterial Genera in Patients with Periodontitis: A Prospective Pilot Study

This prospective pilot study aimed to evaluate the effect of minocycline-HCl ointment (MO), locally delivered as an adjunct to scaling and root planing (SRP), on subgingival microflora. A total of 59 periodontitis patients received SRP as an initial periodontal therapy. In the selected periodontal pockets with probing depths (PD) of 6−9 mm, the sites that exhibited a positive reaction following a bacterial test using an immunochromatographic device were subsequently treated with MO (SRP + MO group, n = 25). No additional treatment was performed at sites showing a negative reaction (SRP group, n = 34). In addition to subgingival plaque sampling, measurement of clinical parameters including PD, clinical attachment level (CAL), bleeding on probing (BOP), plaque index and gingival index (GI) were performed at baseline and 4 weeks after the initial periodontal therapy. The subgingival microflora were assessed by terminal restriction fragment-length polymorphism analysis. Relative to baseline values, the mean scores for PD-, CAL-, BOP-, and GI-sampled sites were significantly decreased post treatment in both groups (p < 0.01). The intra-comparisons showed a significant decrease in the counts of the genera Eubacterium, Parvimonas, Filifactor, Veillonella, Fusobacterium, Porphyromonas, Prevotella, and unknown species in the SRP + MO group (p < 0.05). Inter-comparisons indicated a significant decrease in the genera Veillonella in the SRP + MO group (p = 0.01). Combination therapy of SRP and local MO induced a change in the subgingival microbial community: particularly, the number of Veillonella spp. was markedly reduced.

Recommendations for treating stage I-III periodontitis in the Taiwanese population: A consensus report from the Taiwan Academy of Periodontology

BACKGROUND/PURPOSE

Based on the fundamental of the S3-level clinical practice guideline (CPG) for treating stage I-III periodontitis developed by the European Federation of Periodontology (EFP), this consensus report aimed to develop treatment recommendations for treating periodontitis in the Taiwanese population.

METHODS

The report was constructed by experts from the Taiwan Academy of Periodontology. The following topics were reviewed: (a) the prevalence of periodontitis in Asia and current status of treatment in Taiwan; (b) specific anatomical considerations for treating periodontitis in Asians; (d) educational and preventive interventions and supragingival plaque control; (d) subgingival instrumentation and adjunctive treatment; (e) surgical periodontal therapy; and (f) maintenance and supportive periodontal care. Recommendations were made according to the evidences from the EFP CPG, the published literature and clinical studies in Asians, and the expert opinions.

RESULTS

The treatment recommendations for the Taiwanese population were generally in parallel with the EFP CPG, and extra cautions during treatment and maintenance phases were advised due to the anatomical variations, such as shorter root trunk, higher prevalence of supernumerary distolingual root and lingual bony concavity in mandibular posteriors, and thinner anterior labial plate, of the Asian population.

CONCLUSION

The EFP CPG could be adopted for treating periodontitis and maintaining periodontal health of the Taiwanese population, and anatomical variations should be cautious when the treatment is delivered.

Role of IL-6 and STAT3 signaling in dihydropyridine-induced gingival overgrowth fibroblasts

OBJECTIVES

This study analyzed the role of the interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) pathway in dihydropyridine-induced gingival overgrowth (DIGO) fibroblasts.

MATERIALS AND METHODS

Tissue samples were obtained through surgical dissection from five DIGO patients and five healthy individuals. Cell cultures were conditioned with nifedipine (Nif) (0.34 µM) and stimulated with IL-1β (10 ng/ml) to clarify whether IL-6 upregulates extracellular matrix overproduction or has an impact on the cell proliferation rate of DIGO fibroblasts. STAT3 was knocked down using short hairpin (sh)RNA to determine its role in collagen (Col) type I alpha 1 (Colα1(I)) synthesis.

RESULTS

Results showed that phosphorylated (p)STAT3 nuclear translocation was activated by a simulated autocrine concentration (50 ng/ml) of IL-6, and application of an anti-IL-6 antibody significantly decreased the pSTAT3/STAT3 ratio in DIGO fibroblasts. STAT3 knockdown significantly decreased STAT3 and Colα1(I) expressions in DIGO cells. DIGO tissues presented stronger proliferating cell nuclear antigen (PCNA) expression than did healthy individuals under the effect of IL-1β/Nif treatment.

CONCLUSIONS

Gingival inflammation (e.g., IL-1β) and taking dihydropyridine (e.g., Nif) may additively stimulate Col overproduction through the IL-6-STAT3-Colα1(I) cascade in DIGO cells. IL-6-STAT3 signaling may be considered a target for the control of DIGO.

Impact of Local Drug Delivery of Minocycline on the Subgingival Microbiota during Supportive Periodontal Therapy: A Randomized Controlled Pilot Study

The aim of this study was to examine the effect of adjunct local minocycline administration on the microbiological parameters of subgingival plaque samples in the residual periodontal pockets. Ten chronic periodontitis patients under a supportive periodontal therapy regimen were recruited. After subgingival debridement, either 2% minocycline gel, Periocline™, (Test Group) or a placebo (Control Group) was administered to the selected sites once a week for three weeks. Subgingival plaque was collected at baseline, and at four weeks and eight weeks. The microbiological composition was analyzed by 16S ribosomal RNA sequencing. In the Test Group, α-diversity (evenness) decreased compared to the baseline (p = 0.005) and was lower compared to the control group at four weeks (p = 0.003). The microbial community composition between the two groups was significantly different at four weeks (p = 0.029). These changes were attributable to a decrease in the bacteria associated with periodontitis and an increase in the bacteria associated with periodontal health. Additionally, the improvement in bleeding on probing continued at eight weeks; however, there were little microbial effects of 2% minocycline gel observed at eight weeks. The control group demonstrated no change throughout the eight-week experimental period. Thus, local minocycline administration can change the subgingival microbial community of residual periodontal pockets.

Long-term evaluations of teeth and dental implants during dental maintenance period

PURPOSE

This study was designed to evaluate the teeth and dental implants during dental maintenance therapy over 3 years in different conditions after periodontal and dental prosthetic treatment.

MATERIALS AND METHODS

166 patients received maintenance therapy. 59 patients were treated with 2% minocycline-HCl ointment as local drug delivery (LDD) (L group) and 107 patients were treated without LDD (NL group). Clinical data was collected in maintenance period for evaluation. Patients were classified into groups depending on the application of LDD with maintenance therapy, the type of dental treatment before maintenance period (Pre-Tx), the frequency (F-MT), and regularity (R-MT) of maintenance therapy.

RESULTS

The numbers of lost teeth (N-teeth, P=.003) and newly placed dental implants (N-implants, P=.022) are significantly different according to Pre-Tx. F-MT among patients who received surgical dental treatment before maintenance period showed statistical differences in N-teeth (P=.041), but not in N-implants (P=.564). All of the patients in L group showed high F-MT (F-MT1). In NL group, there were no statistical differences in N-teeth or N-implants according to F-MT or R-MT. In F-MT1 group, application of LDD made N-teeth significantly different from both Pre-Tx groups while no significant difference could be found in N-implant. Independent t-test and one-way ANOVA were selected for statistical analysis.

CONCLUSION

The regular maintenance therapy and LDD can be effective for teeth during maintenance period. It is not only pharmacological efficacy in decreasing bacterial species that makes LDD a useful adjunct. Application of LDD also motivates patients to take adequate check-ups in the aspects of both frequency and regularity.

Antibiotic effects against periodontal bacteria in organ cultured tissue

Mechanical reduction of infectious bacteria by using physical instruments is considered the principal therapeutic strategy for periodontal disease; addition of antibiotics is adjunctive. However, local antibiotic treatment, combined with conventional mechanical debridement, has recently been shown to be more effective in periodontitis subjects with type 2 diabetes. This suggests that some bacteria may invade the inflamed inner gingival epithelium, and mechanical debridement alone will be unable to reduce these bacteria completely. Therefore, we tried to establish infected organ culture models that mimic the inner gingival epithelium and aimed to see the effects of antibiotics in these established models. Mouse dorsal skin epithelia were isolated, and periodontal bacteria were injected into the epithelia. Infected epithelia were incubated with test antibiotics, and colony-forming ability was evaluated. Results indicated that effective antibiotics differed according to injected bacteria and the bacterial combinations tested. Overall, in organ culture model, the combination of amoxicillin or cefdinir and metronidazole compensate for the effects of less effective bacterial combinations on each other. This in vitro study would suggest effective periodontal treatment regimens, especially for severe periodontitis.

New Irradiation Method with Indocyanine Green-Loaded Nanospheres for Inactivating Periodontal Pathogens

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive strategy for periodontitis treatments. However, use of aPDT for periodontal treatment is complicated by the difficulty in accessing morphologically complex lesions such as furcation involvement, which the irradiation beam (which is targeted parallel to the tooth axis into the periodontal pocket) cannot access directly. The aim of this study was to validate a modified aPDT method that photosensitizes indocyanine green-loaded nanospheres through the gingivae from outside the pocket using a diode laser. To establish this trans-gingival irradiation method, we built an in vitro aPDT model using a substitution for gingivae. Irradiation conditions and the cooling method were optimized before the bactericidal effects on Porphyromonas gingivalis were investigated. The permeable energy through the gingival model at irradiation conditions of 2 W output power in a 50% duty cycle was comparable with the transmitted energy of conventional irradiation. Intermittent irradiation with air cooling limited the temperature increase in the gingival model to 2.75 °C. The aPDT group showed significant bactericidal effects, with reductions in colony-forming units of 99.99% after 5 min of irradiation. This effect of aPDT against a periodontal pathogen demonstrates the validity of trans-gingival irradiation for periodontal treatment.

Minocycline Ointment as a Local Drug Delivery in the Treatment of Generalized Chronic Periodontitis - A Clinical Study

INTRODUCTION

The primary goal in periodontal therapy includes removal of the etiological factors by mechanical periodontal treatment, which sometimes fail to eliminate the anaerobic infection at the base of the pocket and requires adjuvant chemical therapy.

AIM

The aim of the study was to evaluate the effectiveness of 2% minocycline ointment when used as an adjunct to periodontal flap surgery and post-operative maintenance period for the treatment of generalized chronic periodontitis.

MATERIALS AND METHODS

The study included 30 subjects comprising of 60 posterior sextants in a split mouth design in which 30 sextants were treated as experimental and 30 sextants as control with a probing pocket depth≥6mm. In Group A (experimental group) 30 sextants were treated with open flap debridement followed by the application of minocycline ointment as a local drug delivery. In Group B (control group) 30 sextants were treated with open flap debridement alone. Minocycline hydrochloride ointment was applied on the 0 day and 3(rd) month. The clinical parameters such as plaque index, probing pocket depth, clinical attachment level and gingival bleeding index were recorded at 0 day, 3(rd) month and 6(th) month in both the groups. Paired and unpaired t-test were used to compare the means of the two groups.

RESULTS

When Group A and Group B were compared, Group A showed significantly greater reduction in gingival bleeding index, probing pocket depth and gain in clinical attachment level than Group B, from 0 day to 3 months and from 0 day to 6 months. Group A showed significant reduction in plaque index than Group B when they were compared at 6 months.

CONCLUSION

The results demonstrate that there was significant reduction in the clinical parameters with improvement in the periodontal status on application of minocycline ointment as an adjunct to periodontal flap surgery in generalized chronic periodontitis.

Comparative study to investigate the effect of meloxicam or minocycline HCl in situ gel system on local treatment of periodontal pockets

In situ gelling formulations allow easy application to the target area. Gelation is induced by physiological stimuli at the site of application where the formula attains semisolid properties and exerts sustained drug release. In situ gelling formulations containing either 3% meloxicam (Mx) or 2% minocycline HCl (MH) were prepared for local application into the periodontal pockets. Gel formulations were based on the thermosensitive Pluronic(®) (Pl) and the pH-sensitive Carbopol(®) (C) polymers. C gels were prepared in combination with HPMC (H) to decrease its acidity. The total percent drug released from Pl formulae was 21.72% after 1 week for Mx and 85% after 3 days for MH. Their release kinetics data indicated anomalous non-Fickian behavior that could be controlled by both diffusion and chain relaxation. Addition of MH to C/H gels (1:2.5) resulted in liquefaction, followed by drug precipitation. Regarding C/H gel containing Mx, it showed a prolonged release rate up to 7 days with an initial burst effect; the kinetics data revealed Fickian-diffusion mechanism. The in vitro antibacterial activity studies for MH gel in Pl revealed that the drug released exceeded the minimum inhibitory concentration (MIC) of MH against Staphylococcus aureus ATCC 6538; placebo gel showed no effect on the microorganism. Clinical evaluation of Pl gels containing either Mx or MH showed significant improvement in chronic periodontitis patients, manifested by decrease in pocket depth and gingival index and increase in bone density.

In situ forming implants for periodontitis treatment with improved adhesive properties

Novel in situ forming implants are presented showing a promising potential to overcome one of the major practical hurdles associated with local periodontitis treatment: limited adhesion to the surrounding tissue, resulting in accidental expulsion of at least parts of the implants from the patients' pockets. This leads to high uncertainties in the systems' residence times at the site of action and in the resulting drug exposure. In the present study, the addition of different types and amounts of plasticizers (acetyltributyl citrate and dibutyl sebacate) as well as of adhesive polymers (e.g., cellulose derivatives such as hydroxypropyl methylcellulose) is shown to allow for a significant increase in the stickiness of poly(lactic-co-glycolic acid)-based implants. The systems are formed in situ from N-methyl pyrrolidone-based liquid formulations. Importantly, at the same time, good plastic deformability of the implants can be provided and desired drug release patterns can be fine-tuned using several formulation tools. The antimicrobial activity of this new type of in situ forming implants, loaded with doxycycline hyclate, was demonstrated using the agar well diffusion method and multiple Streptococcus strains isolated from the oral microflora of patients suffering from periodontitis.

Comparative evaluation of locally delivered minocycline and metronidazole in the treatment of periodontitis

Objective:

The aim of this study was to evaluate and compare the efficacy of subgingivally delivered Minocycline microspheres and 25% Metronidazole gel when used as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis.

Materials and Methods:

A randomized, controlled, single center study was conducted involving 60 sites in 20 patients suffering from moderate to advanced chronic periodontitis. Each patient contributed three sites which were randomized to three treatment groups: SRP + insertion of Minocycline microspheres at day 1 (Group A), SRP + insertion of Metronidazole gel at day 1 and at day 7 (Group B), and SRP alone (Group C). Gingival index (GI), plaque index (PI), probing pocket depth (PPD), and clinical attachment level (CAL) were recorded at day 1, 1 month, and 3 months post therapy.

Results:

All treatments showed significant reductions in PPD and CAL at 1 and 3 months when compared to baseline values (P < 0.001). At 3 months, sites treated with minocycline showed an additional reduction in PPD of 0.85 ± 0.03 mm, significantly greater than SRP alone. Differences in mean PPD reduction between Group B and Group C and between Group A and Group B were not significant. At 3 months, difference in CAL gain between Group A and C was 0.50 ± 0.45, which was statistically significant and between Group B and C was 0.35 ± 0.11, which was not found to be statistically significant (P = 0.20). Differences in relative CAL between Group A and Group B were also not found to be statistically significant (P = 0.53).

Conclusion:

The results concluded that treatment with Minocycline microspheres and Metronidazole gel improve PPD and CAL in patients with periodontitis compared to SRP alone.

Non-surgical periodontal therapy with and without subgingival minocycline administration in patients with poorly controlled type II diabetes: a randomized controlled clinical trial

The aim of this study was to evaluate changes in clinical parameters and levels of inflammatory biomarkers in plasma in periodontal patients with poorly controlled type 2 diabetes mellitus (T2DM) after non-surgical periodontal therapy. Twenty-eight poorly controlled T2DM patients were randomly assigned to treatment with scaling and root planning (SRP) and SRP + subgingival minocycline administration. Clinical parameters, including the probing depth (PD), bleeding on probing (BOP), plaque score (PS), clinical attachment level (CAL), and plasma interleukin (IL)-6, soluble receptor of advanced glycation end products (sRAGE), chronic reactive protein (CRP), and hemoglobin A1c (HbA1c) were measured before and after a 6-month treatment period. Significant changes in PD, BOP, PS, and CAL were found in both groups. The latent growth curve model showed an overall reduction in the log HbA1c level in the SRP group (-0.082, p = 0.033). Small changes in the log sRAGE level and log CRP level in plasma were found in both groups. IL-6 in the plasma increased in the SRP group, but slightly decreased in the SRP+minocycline group (0.469 pg/ml, p = 0.172). Non-surgical periodontal therapy with or without subgingival minocycline application may achieve significant periodontal improvement and moderate improvement in HbA1c, but had no significant effect on plasma levels of IL-6, CRP, or sRAGE in patients with poorly controlled T2DM. For patients with both periodontal diseases and diabetes, non-surgical periodontal treatments may be helpful in their diabetic control.

A role for non-antimicrobial actions of tetracyclines in combating oxidative stress in periodontal and metabolic diseases: a literature review

This review addresses the role of adjunctive tetracycline therapy in the management of periodontal diseases and its efficacy in reducing inflammatory burden, oxidative stress and its sequelae in patients with coexisting features of metabolic syndrome. Removal of the dimethylamine group at C4 of the tetracycline molecule reduces its antibiotic properties, enhancing its non-antimicrobial actions; this strategy has aided the development of several chemically modified tetracyclines such as minocycline and doxycycline, by altering different regions of the molecule for focused action on biological targets. Tetracyclines are effective in reducing inflammation by inhibiting matrix metalloproteinases, preventing excessive angiogenesis, inhibiting apoptosis and stimulating bone formation. There are important applications for tetracyclines in the management of diabetic, dyslipidaemic periodontal patients who smoke. The diverse mechanisms of action of tetracyclines in overcoming oxidative stress and enhancing matrix synthesis are discussed in this review.

Antimicrobial therapy using a local drug delivery system (Arestin) in the treatment of peri-implantitis. I: Microbiological outcomes

OBJECTIVES

To assess the microbiological outcome of local administration of minocycline hydrochloride microspheres 1 mg (Arestin) in cases with peri-implantitis and with a follow-up period of 12 months.

MATERIAL AND METHODS

After debridement, and local administration of chlorhexidine gel, peri-implantitis cases were treated with local administration of minocycline microspheres (Arestin). The DNA-DNA checkerboard hybridization method was used to detect bacterial presence during the first 360 days of therapy.

RESULTS

At Day 10, lower bacterial loads for 6/40 individual bacteria including Actinomyces gerensceriae (P<0.1), Actinomyces israelii (P<0.01), Actinomyces naeslundi type 1 (P<0.01) and type 2 (P<0.03), Actinomyces odontolyticus (P<0.01), Porphyromonas gingivalis (P<0.01) and Treponema socranskii (P<0.01) were found. At Day 360 only the levels of Actinobacillus actinomycetemcomitans were lower than at baseline (mean difference: 1x10(5); SE difference: 0.34x10(5), 95% CI: 0.2x10(5) to 1.2x10(5); P<0.03). Six implants were lost between Days 90 and 270. The microbiota was successfully controlled in 48%, and with definitive failures (implant loss and major increase in bacterial levels) in 32% of subjects.

CONCLUSIONS

At study endpoint, the impact of Arestin on A. actinomycetemcomitans was greater than the impact on other pathogens. Up to Day 180 reductions in levels of Tannerella forsythia, P. gingivalis, and Treponema denticola were also found. Failures in treatment could not be associated with the presence of specific pathogens or by the total bacterial load at baseline. Statistical power analysis suggested that a case control study would require approximately 200 subjects.