Inflammatory external root resorption following surgical treatment for intra-bony defects: a report of two cases involving EmdogainR and a review of the literature

Combination of enamel matrix derivative and hyaluronic acid inhibits lipopolysaccharide-induced inflammatory response on human epithelial and bone cells

Objectives

The aim of this study was to evaluate the in vitro effect of enamel matrix derivative (EMD) and hyaluronic acid (HA) and their synergistic combination on lipopolysaccharides (LPS)-induced inflammation in human keratinocytes and osteoblasts.

Material and methods

Cells were challenged with LPS (1 μg/ml) and cultured in the following treatment groups with EMD (30 mg/ml) and HA (30 mg/ml): LPS, EMD, HA, EMD + HA, EMD + LPS, HA + LPS, and EMD + HA + LPS. Cell viability, inflammatory cytokine expression, and cell migration were determined using colorimetric assay, quantitative real-time polymerase chain reaction (qPCR), and scratch wound healing assay, respectively.

Results

Cell viability was decreased when exposed to LPS compared to the controls. Overall, LPS treatment expressed upregulation on inflammatory cytokine tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). EMD and HA reduced up to 3.0-fold the cytokine expression caused by LPS (p < 0.05). EMD and HA statistically induced higher migration in osteoblasts and keratinocytes, respectively. Migration was impaired by LPS, whereas it significantly increased after addition of EMD and HA.

Conclusions

EMD and HA are advantageous biomaterials that individually generate strong directional migratory keratinocyte and osteoblast response. Their combination also enhances cell viability, and anti-inflammatory and migratory abilities to promote healing specially under LPS inflammatory stimulus. Future in vivo and animal research is necessary to further characterize the effect of EMD and HA on periodontal regeneration.

Clinical relevance

The use of EMD in conjunction with HA resulted in a reduction of inflammation and improvement of tissue healing at wound sites. Both biomaterials combined may potentially improve the effectiveness of bone regeneration in periodontal bone defects, pointing to the potential clinical relevance of both materials in regenerative periodontal surgery.

Interventions for the management of external root resorption

BACKGROUND

External root resorption is a pathological process, which tends to occur following a wide range of mechanical or chemical stimuli such as infection, pressure, trauma or orthodontic tooth movement. Although it is predominantly detected by radiography, in some cases root resorption may be identified by clinical symptoms such as pain, swelling and mobility of the tooth. Treatment alternatives are case-dependent and aim to address the cause of the resorption and aid the regeneration of the resorptive lesion.

OBJECTIVES

To evaluate the effectiveness of any interventions that can be used in the management of external root resorption in permanent teeth.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 14 October 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 9), MEDLINE via OVID (1946 to 14 October 2015) and EMBASE via OVID (1980 to 14 October 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials of permanent teeth with any type of external root resorption, which has been confirmed by clinical and radiological examination, comparing one type of intervention (root canal medications and canal filling, splinting or extraction of teeth or the surgical removal of any relevant pathology) with another, or with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two review authors screened search records independently. Full papers were obtained for potentially relevant trials. If data had been extracted, the statistical guidelines set out in the Cochrane Handbook would have been followed.

MAIN RESULTS

No randomised controlled trials that met the inclusion criteria were identified. However, we identified one ongoing study that is potentially relevant to this review and will be assessed when it is published.

AUTHORS' CONCLUSIONS

We were unable to identify any reports of randomised controlled trials regarding the efficacy of different interventions for the management of external root resorption. In view of the lack of reliable evidence on this topic, clinicians must decide on the most appropriate means of managing this condition according to their clinical experience with regard to patient-related factors. There is a need for well designed and conducted clinical trials on this topic, which conform to the CONSORT statement (www.consort-statement.org/).

Tissue engineered periodontal products

Attainment of periodontal regeneration is a significant clinical goal in the management of advanced periodontal defects arising from periodontitis. Over the past 30 years numerous techniques and materials have been introduced and evaluated clinically and have included guided tissue regeneration, bone grafting materials, growth and other biological factors and gene therapy. With the exception of gene therapy, all have undergone evaluation in humans. All of the products have shown efficacy in promoting periodontal regeneration in animal models but the results in humans remain variable and equivocal concerning attaining complete biological regeneration of damaged periodontal structures. In the early 2000s, the concept of tissue engineering was proposed as a new paradigm for periodontal regeneration based on molecular and cell biology. At this time, tissue engineering was a new and emerging field. Now, 14 years later we revisit the concept of tissue engineering for the periodontium and assess how far we have come, where we are currently situated and what needs to be done in the future to make this concept a reality. In this review, we cover some of the precursor products, which led to our current position in periodontal tissue engineering. The basic concepts of tissue engineering with special emphasis on periodontal tissue engineering products is discussed including the use of mesenchymal stem cells in bioscaffolds and the emerging field of cell sheet technology. Finally, we look into the future to consider what CAD/CAM technology and nanotechnology will have to offer.

Root maturation and dentin-pulp response to enamel matrix derivative in pulpotomized permanent teeth

The success of pulpotomy of young permanent teeth depends on the proper selection of dressing materials. This study aimed to evaluate the histological and histomorphometric response of dentin–pulp complex to the enamel matrix derivative (Emdogain^® gel) compared to that of calcium hydroxide when used as a pulp dressing in immature young permanent dogs’ teeth. Dentin-like tissues bridging the full width of the coronal pulp at the interface between the injured and healthy pulp tissues were seen after 1 month in both groups. With time, the dentin bridge increased in thickness for calcium hydroxide but disintegrated and fully disappeared for Emdogain-treated group. Progressive inflammation and total pulp degeneration were only evident with Emdogain-treated group. The root apices of Emdogain-treated teeth became matured and closed by cementum that attached to new alveolar bone by a well-oriented periodontal ligament. In young permanent dentition, Emdogain could be a good candidate for periodontium but not dentino–pulpal complex regeneration.

TGF-βRI kinase activity mediates Emdogain-stimulated in vitro osteoclastogenesis

OBJECTIVES

Emdogain, containing an extract of fetal porcine enamel matrix proteins, is a potent stimulator of in vitro osteoclastogenesis. The underlying molecular mechanisms are, however, unclear.

MATERIAL AND METHODS

Here, we have addressed the role of transforming growth factor-beta receptor type 1 (TGF-βRI) kinase activity on osteoclastogenesis in murine bone marrow cultures.

RESULTS

Inhibition of TGF-βRI kinase activity with SB431542 abolished the effect of Emdogain on osteoclastogenesis induced by receptor activator of nuclear factor kappa-B ligand or tumor necrosis factor-alpha. SB431542 also suppressed the Emdogain-mediated increase of OSCAR, a co-stimulatory protein, and dendritic cell-specific transmembrane protein and Atp6v0d2, the latter two being involved in cell fusion. Similar to transforming growth factor-beta1 (TGF-β), Emdogain could not compensate for the inhibition of IL-4 and IFNγ on osteoclast formation. When using the murine macrophage cell line RAW246.7, SB431542 and the smad-3 inhibitor SIS3 blocked Emdogain-stimulated expression of the transcription factor NFATc1.

CONCLUSIONS

Taken together, the data suggest that TGF-βRI kinase activity is necessary to mediate in vitro effects of Emdogain on osteoclastogenesis.

CLINICAL RELEVANCE

Based on these in vitro data, we can speculate that at least part of the clinical effects of Emdogain on osteoclastogenesis is mediated via TGF-β signaling.

Interventions for the management of external root resorption

BACKGROUND

External root resorption is a pathological process which tends to occur following a wide range of mechanical or chemical stimuli such as infection, pressure, trauma or orthodontic tooth movement. Although it is predominantly detected by radiography, in some cases, root resorption may be identified by clinical symptoms i.e. pain, swelling and mobility of the tooth. Treatment alternatives are case-dependant and aim at the removal of the cause and the regeneration of the resorptive lesion.

OBJECTIVES

To evaluate the effectiveness of any interventions that can be used in the management of external root resorption in permanent teeth.

SEARCH STRATEGY

We searched the following databases in April 2010: The Cochrane Oral Health Group's Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 3); MEDLINE (via OVID) (1950 to April 2010); and EMBASE (via OVID) (1980 to April 2010). We also searched two regional bibliographic databases (IndMED and Iranmedex) and handsearched five Iranian dental journals using free text terms appropriate for this review.

SELECTION CRITERIA

Randomised controlled trials comparing any type of intervention including root canal medications and canal filling, splinting or extraction of teeth or the surgical removal of any relevant pathology with each other, or placebo or no treatment applied to permanent teeth with any type of external root resorption which had been confirmed by clinical and radiological examination.

DATA COLLECTION AND ANALYSIS

Two review authors conducted screening of studies in duplicate and independently. The Cochrane Collaboration statistical guidelines were to be followed.

MAIN RESULTS

66 trials were identified in our searches none of which matched our inclusion criteria. However, we identified one ongoing study which is potentially relevant to this review and will be assessed when it is published.

AUTHORS' CONCLUSIONS

We were unable to identify any reports of randomised controlled trials regarding the efficacy of different interventions for the management of external root resorption. In view of the lack of any high level evidence on this topic, it is suggested that clinicians decide on the most appropriate means of managing this condition according to their clinical experience with regard to patient related factors. Future research should consist of robust clinical trials which conform to the CONSORT statement (www.consort-statement.org/).

Enamel matrix derivative (Emdogain(R)) for periodontal tissue regeneration in intrabony defects

BACKGROUND

Periodontitis is a chronic infective disease of the gums caused by bacteria present in dental plaque. This condition induces the breakdown of the tooth supporting apparatus until teeth are lost. Surgery may be indicated to arrest disease progression and regenerate lost tissues. Several surgical techniques have been developed to regenerate periodontal tissues including guided tissue regeneration (GTR), bone grafting (BG) and the use of enamel matrix derivative (EMD). EMD is an extract of enamel matrix and contains amelogenins of various molecular weights. Amelogenins are involved in the formation of enamel and periodontal attachment formation during tooth development.

OBJECTIVES

To test whether EMD is effective, and to compare EMD versus GTR, and various BG procedures for the treatment of intrabony defects.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE. Several journals were handsearched. No language restrictions were applied. Authors of randomised controlled trials (RCTs) identified, personal contacts and the manufacturer were contacted to identify unpublished trials. Most recent search: February 2009.

SELECTION CRITERIA

RCTs on patients affected by periodontitis having intrabony defects of at least 3 mm treated with EMD compared with open flap debridement, GTR and various BG procedures with at least 1 year follow up. The outcome measures considered were: tooth loss, changes in probing attachment levels (PAL), pocket depths (PPD), gingival recessions (REC), bone levels from the bottom of the defects on intraoral radiographs, aesthetics and adverse events. The following time-points were to be evaluated: 1, 5 and 10 years.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two authors. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). It was decided not to investigate heterogeneity, but a sensitivity analysis for the risk of bias of the trials was performed.

MAIN RESULTS

Thirteen trials were included out of 35 potentially eligible trials. No included trial presented data after 5 years of follow up, therefore all data refer to the 1-year time point. A meta-analysis including nine trials showed that EMD treated sites displayed statistically significant PAL improvements (mean difference 1.1 mm, 95% CI 0.61 to 1.55) and PPD reduction (0.9 mm, 95% CI 0.44 to 1.31) when compared to placebo or control treated sites, though a high degree of heterogeneity was found. Significantly more sites had < 2 mm PAL gain in the control group, with RR 0.53 (95% CI 0.34 to 0.82). Approximately nine patients needed to be treated (NNT) to have one patient gaining 2 mm or more PAL over the control group, based on a prevalence in the control group of 25%. No differences in tooth loss or aesthetic appearance as judged by the patients were observed. When evaluating only trials at a low risk of bias in a sensitivity analysis (four trials), the effect size for PAL was 0.62 mm (95% CI 0.28 to 0.96), which was less than 1.1 mm for the overall result. Comparing EMD with GTR (five trials), GTR showed statistically significant more postoperative complications (three trials, RR 0.12, 95% CI 0.02 to 0.85) and more REC (0.4 mm 95% CI 0.15 to 0.66). The only trial comparing EMD with a bioactive ceramic filler found statistically significant more REC (-1.60 mm, 95% CI -2.74 to -0.46) at the EMG treated sites.

AUTHORS' CONCLUSIONS

One year after its application, EMD significantly improved PAL levels (1.1 mm) and PPD reduction (0.9 mm) when compared to a placebo or control, however, the high degree of heterogeneity observed among trials suggests that results have to be interpreted with great caution. In addition, a sensitivity analysis indicated that the overall treatment effect might be overestimated. The actual clinical advantages of using EMD are unknown. With the exception of significantly more postoperative complications in the GTR group, there was no evidence of clinically important differences between GTR and EMD. Bone substitutes may be associated with less REC than EMD.

The application of an enamel matrix protein derivative (Emdogain) in regenerative periodontal therapy: a review

Regenerative periodontal therapy aims at reconstitution of the lost periodontal structures such as new formation of root cementum, periodontal ligament and alveolar bone. Findings from basic research indicate that enamel matrix protein derivative (EMD) has a key role in periodontal wound healing. Histological results from animal and human studies have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. This review aims to present an overview of evidence-based clinical indications for regenerative therapy with EMD.