Is there a temporal trend in the reported treatment efficacy of periodontal regeneration? A meta-analysis of randomized-controlled trials

Enhanced immunomodulation and periodontal regeneration efficacy of subgingivally delivered progranulin-loaded hydrogel as an adjunct to non-surgical treatment for Class II furcation involvement in dogs

AIM

To evaluate the effect of subgingival delivery of progranulin (PGRN)/gelatin methacryloyl (GelMA) complex as an adjunct to scaling and root planing (SRP) on an experimental periodontitis dog model with Class II furcation involvement (FI).

MATERIALS AND METHODS

A Class II FI model was established, and the defects were divided into four treatment groups: (a) no treatment (control); (b) SRP; (c) SRP + GelMA; (d) SRP + PGRN/GelMA. Eight weeks after treatment, periodontal parameters were recorded, gingival crevicular fluid and gingival tissue were collected for ELISA and RT-qPCR, respectively, and mandibular tissue blocks were collected for micro computed tomography (micro-CT) scanning and hematoxylin and eosin (H&E) staining.

RESULTS

The SRP + PGRN/GelMA group showed significant improvement in all periodontal parameters compared with those in the other groups. The expression of markers related to M1 macrophage and Th17 cell significantly decreased, and the expression of markers related to M2 macrophage and Treg cell significantly increased in the SRP + PGRN/GelMA group compared with those in the other groups. The volume, quality and area of new bone and the length of new cementum in the root furcation defects of the PGRN/GelMA group were significantly increased compared to those in the other groups.

CONCLUSIONS

Subgingival delivery of the PGRN/GelMA complex could be a promising non-surgical adjunctive therapy for anti-inflammation, immunomodulation and periodontal regeneration.

Early Optimistic Effect in Periodontology and Implant Dentistry Trials

Differences in effect estimates between early primary trials included in a meta-analysis and the pooled estimate of meta-analysis might indicate potential novelty bias. The objective of this study was to assess the presence of novelty bias in a sample of studies published in periodontology and implant dentistry. On August 7, 2020, we searched the PubMed database for meta-analyses of clinical studies published between August 2015 and August 2020. Meta-analyses with at least 4 primary studies were selected for assessment. We fitted logistic regression models using trial characteristics as predictors to assess the association between these characteristics and 1) the odds of the first trial's estimate to be included in the meta-analysis confidence interval (CI) and 2) the odds of overlap between the first trial's CI and the meta-analysis prediction interval (PI). Ninety-two meta-analyses provided data for assessment. In absolute values, 70% of the meta-analyses have a pooled estimate smaller than the corresponding estimate of the first trial, although there was overlap of the CI of estimates from the first trial and the meta-analysis in 87% of the cases. This is probably due to the small number of trials in most meta-analyses and the subsequently large uncertainty associated with the pooled effect estimate. As the number of trials in the meta-analysis increased, the odds of the treatment effect estimate of the first trial to be included in the meta-analysis CI decreased by 15% for every additional trial (odds ratio, 0.85; 95% CI, 0.73 to 0.96). Meta-analytic effect estimates appear to be more conservative than those from the first trial in the meta-analysis. Our findings show evidence of novelty bias in periodontology and implant dentistry; therefore, clinicians should be aware of the risk of making decisions based on the information reported in new trials because of the risk of exaggerated estimates in these trials.

Clinical and radiographic evaluation of 0.8% hyaluronic acid as an adjunct to open flap debridement in the treatment of periodontal intrabony defects: randomized controlled clinical trial

OBJECTIVES

Present study aimed to evaluate and compare the clinical and radiographic efficacy of 0.8% hyaluronic acid (HA) gel as an adjunct to open flap debridement (OFD) versus open flap debridement (OFD) alone in the treatment of periodontal intrabony defects.

MATERIALS AND METHODS

This randomized, controlled, split-mouth, clinical trial included 20 chronic periodontitis (stage II or III (grades A to B)) patients, having at least two contralateral intrabony defects. Forty bilateral intrabony defects (20 in each group) were randomly divided into test (0.8% HA gel + OFD) and control (OFD + placebo) groups. Clinical parameters evaluated at baseline, 6-months, and 12-months were plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and gingival recession (GR). Using cone beam computed tomography (CBCT), radiographic parameters were evaluated at baseline and 12 months. This included bone defect fill (DF), alveolar crest changes (ACC), and defect resolution (DR). CAL served as the primary outcome variable.

RESULTS

After 12 months, the test group showed significantly greater CAL gain (5.1 ± 1.2 versus 4.05 ± 1.19 mm) and bone defect fill (DF) (5.67 ± 2.01 versus 4.49 ± 1.78 mm) compared to the control group. Mean PD reduction in the test group (5.3 ± 1.2 versus 4.35 ± 0.81 mm) was statistically significant compared to the control group at 12-month period. The control group showed statistically significant increase in GR (1.2 ± 0.76 versus 0.7 ± 0.73 mm) compared to the test group after 12 months.

CONCLUSION

Application of hyaluronic acid gel in conjunction with open flap debridement resulted in enhanced clinical and radiographic outcomes compared to open flap debridement alone.

CLINICAL RELEVANCE

Adjunctive application of HA gel in open flap debridement may improve clinical and radiographic outcomes.

CLINICAL TRIAL REGISTERED NUMBER

CTRI/2018/03/012334.

Effect of Flap Design for Enamel Matrix Derivative Application in Intraosseous Defects

Objective:

To systematically review the literature addressing the focused question: What is the effectiveness of different surgical and nonsurgical procedures combined with enamel matrix derivative (EMD) on clinical, radiographic, and patient-centered outcomes in intraosseous defects?

Methods:

Electronic (Medline, Scopus, and Cochrane databases) and hand literature searches were performed for studies including at least 1 treatment arm where EMD had been applied according to 1 of the following procedures: modified Widman flap; papilla preservation variants (PPVs), including papilla preservation technique, modified papilla preservation technique, and simplified papilla preservation technique; minimally invasive variants, including minimally invasive surgical approach and minimally invasive surgical technique; single-flap variants (SFVs), including single-flap approach and modified minimally invasive surgical technique; or nonsurgical application (flapless approach). Data from 42 selected articles were used to perform a network meta-analysis, and a hierarchy of surgical and nonsurgical applications of EMD was built separately for EMD and EMD + graft based on 6- to 12-mo clinical and radiographic outcomes.

Results:

Among surgical approaches, EMD was associated with best regenerative outcomes when applied through SFVs, with a mean clinical attachment level gain of 3.93 mm and a reduction in the intrabony component of the defect of 3.35 mm. For EMD + graft, limited differences in regenerative outcomes were observed among surgical procedures. PPVs were associated with the highest residual probing depth for EMD (4.08 mm) and EMD + graft (4.32 mm).

Conclusions:

In the treatment of periodontal intraosseous defects, 1) SFVs appear to optimize the regenerative outcomes of EMD; 2) substantial regenerative outcomes can be obtained with SFVs and conservative double flaps (i.e., PPVs and minimally invasive variants) when EMD is combined with a graft; and 3) residual probing depth was higher following PPVs for EMD and EMD + graft.

Knowledge Transfer Statement:

The results of the present systematic review and meta-analysis can be used by clinicians to identify the most effective surgical or nonsurgical procedure to treat an intraosseous defect with EMD or EMD + graft. The main findings indicate that when EMD application is indicated, surgical access based on a single flap seems the most appropriate to optimize clinical outcomes. The application of EMD + graft can be effectively combined with single flaps and conservative double flaps.

Combination of a biomolecule-aided biphasic cryogel scaffold with a barrier membrane adhering PDGF-encapsulated nanofibers to promote periodontal regeneration

OBJECTIVE AND BACKGROUND

To achieve periodontal regeneration, numerous investigations have concentrated on biomolecule supplement and optimization of bone substitute or barrier membrane. This study evaluated the benefit of combining these strategies for periodontal regeneration.

METHODS

Biphasic cryogel scaffold (BCS) composed of gelatin (ligament phase) and gelatin with beta-tricalcium phosphate/hydroxyapatite (BH) (bone phase) was designed as tested bone substitute, and both enamel matrix derivatives (EMD) and bone morphogenetic protein-2 (BMP-2) were applied to formulate a biomolecule-aided BCS (BBS). Functionally graded membrane (FGM) was designed as tested barrier membrane by adhering PDGF-encapsulated poly(L-lactide-co-D/L-lactide) nanofibers on the conventional membrane (CM). BBS and FGM were characterized and tested for biocompatibility in vitro. Thirty 4 × 4 × 5 mm³ periodontal intrabony defects were created on 6 Beagle dogs. Each defect was evenly assigned to one of the following treatments including BH-CM, BCS-CM, BBS-CM, BH-FGM, BCS-FGM, and BBS-FGM, for 12 weeks. The therapeutic efficiency was assessed by micro-CT and histology.

RESULTS

BCS and FGM sustained the release of biomolecules. The viability of MSCs was maintained in both phases of BCS and was promoted while seeding on the PDGF-encapsulated nanofibers. In CM-covered sites, BBS showed significantly greater osteogenesis (P < .01) and early defect fill (P < .05) relative to BH. FGM significantly promoted osteogenesis (P < .05) in BH-treated sites but showed limited benefit in BBS-treated sites. On denuded roots, cementum deposition was evident in BBS-treated sites.

CONCLUSIONS

PDGF-loaded FGM promoted periodontal osteogenesis, and BBS with EMD-BMP-2 had potential for reconstructing alveolar ridge, periodontal ligament, and cementum. FGM and BBS combination provided limited additional benefit.

Nonsurgical and surgical treatment of periodontitis: how many options for one disease?

Treatment of periodontitis aims at preventing further disease progression with the intentions to reduce the risk of tooth loss, minimize symptoms and perception of the disease, possibly restore lost periodontal tissue and provide information on maintaining a healthy periodontium. Therapeutic intervention includes introduction of techniques to change behavior, such as: individually tailored oral-hygiene instructions; a smoking-cessation program; dietary adjustment; subgingival instrumentation to remove plaque and calculus; local and systemic pharmacotherapy; and various types of surgery. No single treatment option has shown superiority, and virtually all types of mechanical periodontal treatment benefit from adjunctive antimicrobial chemotherapy. Periodontal treatment, because of the chronic nature of periodontitis, is a lifelong commitment to intricate oral-hygiene techniques, which, when properly implemented, will minimize the risk of disease initiation and progression.

A large-scale assessment of temporal trends in meta-analyses using systematic review reports from the Cochrane Library

INTRODUCTION

Previous studies suggest that many systematic reviews contain meta-analyses that display temporal trends, such as the first study's result being more extreme than later studies' or a drift in the pooled estimate. We assessed the extent and characteristics of temporal trends using all Cochrane intervention reports published 2008-2012.

METHODS

We selected the largest meta-analysis within each report and analysed trends using methods including a Z-test (first versus subsequent estimates); generalised least squares; and cumulative sum charts. Predictors considered include meta-analysis size and review group.

RESULTS

Of 1288 meta-analyses containing at least 4 studies, the point estimate from the first study was more extreme and in the same direction as the pooled estimate in 738 (57%), with a statistically significant difference (first versus subsequent) in 165 (13%). Generalised least squares indicated trends in 717 (56%); 18% of fixed effects analyses had at least one violation of cumulative sum limits. For some methods, meta-analysis size was associated with temporal patterns and use of a random effects model, but there was no consistent association with review group.

CONCLUSIONS

All results suggest that more meta-analyses demonstrate temporal patterns than would be expected by chance. Hence, assuming the standard meta-analysis model without temporal trend is sometimes inappropriate. Factors associated with trends are likely to be context specific.

Surgical treatment of the residual periodontal pocket

The ultimate goal of periodontal therapy is to prevent further disease progression in order to reduce the risk of tooth loss. This objective can be achieved through a number of therapeutic modalities comprising both the nonsurgical and surgical phases of periodontal therapy. Nonsurgical periodontal treatment has been shown to control periodontal infection and to arrest progression of the disease in a significant number of cases. However, despite completion of nonsurgical treatment, a number of periodontal pockets, defined as 'residual', often remain. The presence of residual pockets may jeopardize tooth survival and be a risk factor of further disease progression, and ultimately tooth loss. Therefore, the aim of this review is to analyze the knowledge available on the indications for and the performance of periodontal surgical treatment of residual pockets in terms of 'traditional' (clinical, microbiological), patient-based and systemic health outcomes.

Regenerative Treatment of a Cemental Tear Using Enamel Matrix Derivatives: a Ten-Year Follow-up

A patient presented with chronic periapical periodontitis on tooth 45. The root canal was re-treated and a wide apical perforation was closed with MTA® as an apical plug. At reevaluation six month later, the tooth presented with increased mobility, bleeding on probing and probing pocket depths of 9 mm. Despite good periapical healing radio graphically, the tooth showed signs of localized marginal bone loss that was diagnosed as being due to a cemental fracture. The tooth was splinted, a muco-periostal flap was raised and the fragment of cementum was removed. The defect was treated in a regenerative approach, using enamel matrix derivatives (EMD). Six month after therapy, the probing pocket depths decreased to values of ≤ 3 mm and a defect fill was radiographically visible. The 10-year follow up showed a stable situation.

It can be concluded that the occurrence of a local delamination of the root surface may contribute to the development of plaque-induced periodontal destruction. Its removal and the regenerative conditioning of the root surface with EDTA and EMD may result in a, at least partial, resolution of the problem and regeneration of bone at the affected the site.

Quality assessment of systematic reviews on periodontal regeneration in humans

BACKGROUND

Systematic reviews represent the highest form of evidence in the current hierarchy of evidence-based dentistry. Critical analysis of published systematic reviews may help to analyze their strengths and weaknesses and to identify areas that need future improvement. The aim of this overview is to determine and compare the quality of systematic reviews published in the field of periodontal regeneration using established checklists, such as the Assessment of Multiple Systematic Reviews (AMSTAR) guidelines.

METHODS

A systematic search was conducted to retrieve reviews on periodontal regeneration in humans. A total of 14 systematic reviews were selected using a set of inclusion and exclusion criteria. Two independent reviewers appraised the quality of the selected reviews using AMSTAR guidelines. Each article was given an AMSTAR total score, based on the number of AMSTAR criteria that were fulfilled. The quality of included reviews was further assessed using a checklist proposed in 2003.

RESULTS

Only one of the selected systematic reviews satisfied all the AMSTAR guidelines, whereas two reviews satisfied just two of the 11 items. This study shows that published systematic reviews on periodontal regeneration exhibit significant structural and methodologic variability. Quality assessment using the additional checklist further confirmed the variability in the way systematic reviews were conducted and/or reported.

CONCLUSION

Consideration of guidelines for quality assessment, such as AMSTAR, when designing and conducting systematic reviews may increase the validity and clinical applicability of future reviews.

Comparison of the effects of treatment of peri-implant infection in animal and human studies: systematic review and meta-analysis

OBJECTIVE

The main objective of this systematic review is to compare the effects of treatment of peri-implant infection between animal and human studies.

MATERIAL AND METHODS

A literature search was conducted using the Medline, Cochrane Central Register of Controlled Trials, and Latin American and Caribbean Health Sciences Literature databases up to and including May 2008. In addition, bibliographies of systematic reviews on peri-implant diseases were searched manually. Non-surgical and surgical treatments of peri-implantitis/mucositis in animal models or human studies were compared. Meta-analysis was conducted to investigate the difference between the reported treatment effects in animal and human studies. Changes in probing pocket depth (PPD) and probing attachment level (PAL) from baseline measurements were used as measures of outcome. Single-level and multilevel meta-regression analysis was performed by taking into account the different follow-up times of the studies included.

RESULTS

The single-level and multilevel random-effects meta-analysis showed that the difference in PPD reduction [0.31 mm, 95% confidence interval (CI): -0.27, 0.88] and in PAL gain (0.21 mm, 95% CI: -0.47, 0.88) between animal and human studies was not statistically significant. The random-effects meta-regression suggested that studies with longer follow-up times revealed greater PPD reduction (0.25 mm per month, 95% CI: 0.14, 0.35). However, when the different follow-up times were taken into account, these differences became greater. Substantial heterogeneity between studies was found in the meta-analyses (I(2)=97.6% for animal studies and 99.9% for human studies).

CONCLUSION

There was great heterogeneity between human and animal studies in terms of study designs and treatment procedures. Therefore, the results from this meta-analysis should be interpreted with caution. Heterogeneity between studies and its causes merit further investigations.

Partial least squares path modelling for relations between baseline factors and treatment outcomes in periodontal regeneration

BACKGROUND

Some clinical outcome variables in periodontal research are mathematically coupled, and it is not feasible to include all the mathematically coupled variables in an ordinary least squares (OLS) regression analysis. The simplest solution to this problem is to drop at least one of the mathematically coupled variables. However, this solution is not satisfactory when the mathematically coupled variables have distinctive clinical implications.

MATERIAL AND METHODS

Partial least squares (PLS) methods were used to analyse data from a study on guided tissue regeneration. Relationships between characteristics of baseline lesions and treatment outcomes after 1 year were analysed using PLS, and the results were compared with those from OLS regression.

RESULTS

PLS analysis suggested that there were multiple dimensions in the characteristics of baseline lesion: vertical dimension was positively associated with probing pocket depth (PPD) reduction and clinical attachment level (CAL) gain, whilst horizontal dimension was negatively associated with the outcome. Baseline gingival recession had a negative association with PPD reduction but a small positive one with CAL gain.

CONCLUSION

PLS analysis provides new insights into the relationships between baseline characteristics of infrabony defects and periodontal treatment outcomes. The hypothesis of multiple dimensions in baseline lesions needs to be validated by further analysis of different datasets.