Deproteinized bovine bone derived with collagen improves soft and bone tissue outcomes in flapless immediate implant approach and immediate provisionalization: a randomized clinical trial

Critical review on bone grafting during immediate implant placement

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

Buccal bone thickness and mid-facial soft tissue recession after various surgical approaches for immediate implant placement: A systematic review and network meta-analysis of controlled trials

AIM

To evaluate the relative efficacy and confidence in the precision of the results of different surgical interventions for immediate implant placement in the anterior area.

MATERIALS AND METHODS

Electronic searches were performed in PubMed, Embase, and Cochrane CENTRAL. Randomized controlled trials comparing different surgical techniques in anterior jaws for type 1 implant placement were included. Outcome measures included implant survival (primary outcome), buccal bone thickness (BBT) reduction, and mid-facial soft tissue recession (MSTR). Risks of bias assessment, network meta-analysis (NMA), sensitivity analysis, and quality-of-evidence assessment were performed.

RESULTS

Twenty-two studies reporting on 948 subjects and 5 surgical interventions were included. Fourteen early failures were reported. Compared with open-flap surgery without tissue augmentation (F-N) and looking at BBT preservation, NMA showed that there was moderate confidence that flapless surgery with hard tissue augmentation (FL-HTA) was better than flapless surgery without tissue augmentation (FL-N) or open-flap surgery with hard tissue augmentation (F-HTA) (mean difference -0.8 mm, 95% confidence interval: -1.1 to -0.5 mm; -0.6 mm, -0.9 to -0.4 mm; and -0.5 mm, -0.7 to -0.3 mm, respectively). There was moderate confidence that flapless surgery with hard and soft tissue augmentation (FL-HTA&STA) could significantly prevent MSTR compared with FL-HTA (-0.5 mm, -0.7 to -0.3 mm) and FL-N (-0.6 mm, -1.2 to -0.04 mm). However, there was no significant additional benefit in BBT with the FL-HTA&STA approach compared to the FL-HTA approach (-0.30 mm, -0.81 to 0.21 mm).

CONCLUSIONS

For immediate implant placement in the anterior areas, the FL-HTA approach better preserves BBT (moderate confidence); adding STA improves the stability of the mid-facial soft tissue level (moderate confidence) but at the expense of BBT (low confidence).

Collagen-Based Biomaterials for Tissue Engineering

Collagen is commonly used as a regenerative biomaterial due to its excellent biocompatibility and wide distribution in tissues. Different kinds of hybridization or cross-links are favored to offer improvements to satisfy various needs of biomedical applications. Previous reviews have been made to introduce the sources and structures of collagen. In addition, biological and mechanical properties of collagen-based biomaterials, their modification and application forms, and their interactions with host tissues are pinpointed. However, there is still no review about collagen-based biomaterials for tissue engineering. Therefore, we aim to summarize and discuss the progress of collagen-based materials for tissue regeneration applications in this review. We focus on the utilization of collagen-based biomaterials for bones, cartilages, skin, dental, neuron, cornea, and urological applications and hope these experiences and outcomes can provide inspiration and practical techniques for the future development of collagen-based biomaterials in related application fields. Moreover, future improving directions and challenges for collagen-based biomaterials are proposed as well.

Influence of using collagen on the soft and hard tissue outcomes of immediate dental implant placement: A systematic review and meta-analysis

OBJECTIVE

To compare the effects of bone grafting materials, collagen-infused grafting materials, and no grafting materials on the soft and hard tissue outcomes when an immediate implant is placed.

MATERIALS AND METHODS

In addition to hand searching, electronic searches were performed in Pubmed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL). Only RCTs were included in our review. The Cochrane ROB 2.0 tool was used to assess the risk of bias (ROB). Two subgroups were used to evaluate implant failure rate, buccal bone resorption, soft tissue thickness, and esthetic scores. In the meta-analysis, both the fixed-effects model and the random-effects model were employed.

RESULT

7 RCTs were selected after screening 580 studies, and 205 patients were included in the review, with 279 implants. Two RCTs were at low bias of risk, three were at moderate bias, and two were deemed at high risk of bias. The failure rate (95% CI: 0.17 to 11.84) and soft tissue thickness were not significantly different between collagen with bone grafting materials and without bone grafting materials. On the basis of the failure rate and buccal bone thickness, there was no significant difference between collagen with bone grafting materials and bone grafting materials. While we found collagen with bone grafting materials could have a significant advantage on the buccal bone thickness (MD: -0.43,95% CI -0.72 to -0.41) and esthetic outcome (MD: -1.23,95% CI -1.90 to -0.55).

CONCLUSION

In the statement of immediate implant implantation, the thickness of the buccal bone and esthetic outcomes did significantly benefit from bone grafting materials with collagen inserted in the "jumping gap".

Dimensional changes of peri-implant tissue following immediate flapless implant placement and provisionalization with or without xenograft in the anterior maxilla: a study protocol for a randomized controlled trial

Background

Dental implant therapy requires the preservation of peri-implant tissue in the cosmetic zone. Various surgical procedures have been presented, including ridge preservation, flapless method, and quick provisionalization. The goal of this research was to assess the buccal bone dimensional changes following immediate flapless implant implantation in the front maxilla, with or without xenografting.

Method and design

Thirty patients who meet the inclusion criteria and have maxillary teeth (numbers 14 to 24) are candidates for the immediate implant with immediate provisionalization. Participants will be assigned randomly to one of two groups: (1) an immediate implant with xenograft and (2) an immediate implant without bone grafting. For 3 months, the temporary prosthesis will be installed shortly before the final restoration. Following temporary prosthesis insertion and 6 months after surgery, a CBCT radiograph will be used to examine bone tissue. Soft tissue will be assessed at three points: baseline, 3 months, and 6 months following implant therapy. Patients’ satisfaction, implant failure, prosthesis failure, and complications will be assessed as secondary outcomes after 6 months.

Discussion

The outcomes of this randomized clinical research will show if buccal bone augmentation with xenograft reduces vertical bone and gingiva recession. The findings and patient-reported outcomes will aid in the selection of therapy alternatives for implant treatment patients.

Trial registration

Iranian Registry of Clinical Trials IRCT20211119053106N1. Registered on 6 December 2021 and Open Science Framework (OSF) on May 20, 2022. Registration DOI https://doi.org/10.17605/OSF.IO/VUGFQ.

Immediate implant placement with or without socket grafting: A systematic review and meta-analysis

OBJECTIVES

To assess the effect of grafting the gap (SG) between the implant surface and alveolar socket on hard and soft tissue changes following single immediate implant placement (IIP).

MATERIALS AND METHODS

Two independent reviewers conducted an electronic literature search in Pubmed, Web of Science, Embase and Cochrane databases as well as a manual search to identify eligible clinical studies up to August 2021. Randomized controlled trials (RCTs) comparing IIP with and without SG were included for a qualitative analysis. Meta-analyses were performed when possible.

RESULTS

Out of 3627 records, 15 RCTs were selected and reported on 577 patients who received 604 single immediate implants (IIP + SG: 298 implants in 292 patients; IIP: 306 implants in 285 patients) with a mean follow-up ranging from 4 to 36 months. Two RCTs showed low risk of bias. Meta-analysis revealed 0.59 mm (95% CI [0.41; 0.78], p < 0.001) or 54% less horizontal buccal bone resorption following IIP + SG when compared to IIP alone. In addition, 0.58 mm (95% CI [0.28; 0.88], p < 0.001) less apical migration of the midfacial soft tissue level was found when immediate implants were installed with SG. A trend towards less distal papillary recession was found (MD 0.60 mm, 95% CI [-0.08; 1.28], p = 0.080) when SG was performed, while mesial papillae appeared not significantly affected by SG. Vertical buccal bone changes were also not significantly affected by SG. Insufficient data were available for meta-analyses on horizontal midfacial soft tissue changes, pink esthetic score, marginal bone level changes, probing depth and bleeding on probing. Based on GRADE guidelines, a moderate recommendation for SG following IIP can be made.

CONCLUSION

SG may contribute to horizontal bone preservation and soft tissue stability at the midfacial aspect of immediate implants. Therefore, SG should be considered as an adjunct to IIP in clinical practice.

A novel approach to assess volumetric bone loss at immediate implant sites and comparison to linear measurements: a pilot study and measurement workflow

OBJECTIVES

Studies have evaluated changes in hard tissue following immediate implant placement (IIP) through cone beam computed tomography (CBCT) imaging, typically examining the amount of two-dimensional (2D) linear, rather than three-dimensional (3D) volumetric bone loss. This study compared the 3D volumetric changes of the alveolar bone at immediate implant sites with 2D linear measurement outcomes by using a novel image analysis workflow.

METHODS

Preoperative and 6-month postoperative CBCT images of patients who underwent IIP and bone grafting in the maxillary esthetic area were acquired. Linear and volumetric measurements of buccal bone dimensions were taken using a specially designed workflow. The 2D and 3D measurements were compared, and their correlations were determined.

RESULTS

Images from 13 patients (13 implants) were analyzed. Linear measurements revealed that the general linear buccal bone loss was less than 1mm in all segments. The 3D volumetric bone reduction (reported as median [first quantile, third quantile]) in the vertical, cervical, middle, and apical segments was 14.27 [11.33, 30.66] mm³ (51.30 [42.78, 66.91]%), 16.20 [10.35, 30.52] mm³ (18.20 [9.88, 24.74]%), 17.48 [8.42, 21.17] mm³ (24.05 [12.39, 28.22]%), and 6.87 [3.88, 9.45] mm³ (11.34 [5.14, 22.54]%), respectively. Significant positive correlations between 2D and 3D measurements were consistently identified in the cervical and middle segments, but no significant correlation was noted in the vertical segment.

CONCLUSIONS

The results revealed that linear measurements could not fully represent volumetric bone dimensional changes. Performing volumetric measurements and 3D rendering could be valuable in presenting the actual amount and topography of peri-implant bone remodeling.

CLINICAL SIGNIFICANCE

Linear measurements only partially represent the real-life event of 3D bone changes at immediate implant sites. Factors affecting hard tissue alterations following IIP should be reassessed using 3D volumetric measurement outcomes.

Efficacy of bone-substitute materials use in immediate dental implant placement: A systematic review and meta-analysis

OBJECTIVE

To assess the efficacy of using a bone substitute material (BSM) in the fixture-socket gap in patients undergoing tooth extraction and immediate implant placement.

MATERIALS AND METHODS

MEDLINE, EMBASE, and CENTRAL databases were searched for randomized controlled trials (RCTs). RCTs were screened for eligibility, and data were extracted by two authors independently. Risk of bias (ROB) was assessed using Cochrane's ROB tool 2.0. Primary outcomes were implant failure, overall complications, and soft-tissue esthetics. Secondary outcomes were vertical buccal bone resorption, vertical interproximal bone resorption, horizontal buccal bone resorption, and mid-buccal mucosal recession. Meta-analysis was performed using random-effects model with generic inverse variance weighing. GRADE was used to grade the certainty of the evidence.

RESULTS

After screening 19 544 potentially eligible references, 20 RCTs were included in this review, with a total of 848 patients (916 sites). Most included RCTs were deemed of some concerns (53%) or at low (38%) risk of bias, except for overall complications (high ROB). Implant failure did not differ significantly RR = 0.92 (confidence intervals [CI] 0.34 to 2.46) between using a BSM compared with not using a BSM (NoBSM). BSM use resulted in less horizontal buccal bone resorption (MD = -0.52 mm [95% CI -0.74 to -0.30]), a higher esthetic score (MD = 1.49 [95% CI 0.46 to 2.53]), but also more complications (RR = 3.50 [95% CI 1.11 to 11.1] compared with NoBSM. Too few trials compared types of BSMs against each other to allow for pooled analyses. The certainty of the evidence was considered moderate for all outcomes except implant failure (low), overall complications (very low), and vertical interproximal bone resorption (very low).

CONCLUSION

BSM use during immediate implant placement reduces horizontal buccal bone resorption and improves the periimplant soft-tissue esthetics. Although BSM use increases the risk of predominantly minor complications.

Efficacy of different surgical techniques for peri-implant tissue preservation in immediate implant placement: a systematic review and meta-analysis

INTRODUCTION

Preserving peri-implant tissues after immediate implant placement (IIP), especially in aesthetic zones, is a topic of interest.

OBJECTIVES

This systematic review investigated the effects of currently available surgical procedures for preserving peri-implant tissue or ensuring dimensional stability following immediate implant placement.

MATERIALS AND METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement's guidelines were followed, and articles were sought on the PubMed and Cochrane databases with no date restrictions. Only randomised clinical trials that evaluated changes in soft and hard tissues around immediately placed implants were included. Statistical analyses were performed, and the studies´ quality was assessed using the Cochrane Collaboration tool. The agreement between reviewers was assessed based on Cohen's kappa statistics.

RESULTS

Of the 14 studies that met the inclusion criteria, 11 were analysed in the meta-analysis (kappa = 0.814; almost perfect agreement). The use of connective tissue grafts resulted in a significantly greater improvement of the facial gingival level (MD = -0.51; 95% CI: -0.76 to -0.31; p = < .001), and the placement of bone grafts significantly reduced the horizontal resorption of the buccal bone (MD = -0.59; 95% CI: -0.78 to -0.39; p < .001).

CONCLUSION

Connective tissue grafts and bone grafts positively influence tissue preservation around immediately placed implants. Neither the flapless technique nor palatal implant positioning resulted in significant improvements to any of the investigated parameters. Additional longitudinal studies are required.

CLINICAL RELEVANCE

This meta-analysis is useful for discerning the effects of soft tissue augmentation, bone grafting, the flapless technique, and palatal implant positioning on preserving peri-implant tissues after immediate implant placement.

Marine spongin incorporation into Biosilicate® for tissue engineering applications: An in vivo study

Biomaterials and bone grafts, with the ability of stimulating tissue growth and bone consolidation, have been emerging as very promising strategies to treat bone fractures. Despite its well-known positive effects of biosilicate (BS) on osteogenesis, its use as bone grafts in critical situations such as bone defects of high dimensions or in non-consolidated fractures may not be sufficient to stimulate tissue repair. Consequently, several approaches have been explored to improve the bioactivity of BS. A promising strategy to reach this aim is the inclusion of an organic part, such as collagen, in order to mimic bone structure. Thus, the present study investigated the biological effects of marine spongin (SPG)-enriched BS composites on the process of healing, using a critical experimental model of cranial bone defect in rats. Histopathological and immunohistochemistry analyzes were performed after two and six weeks of implantation to investigate the effects of the material on bone repair (supplemental material-graphical abstract). Histological analysis demonstrated that for both BS and BS/SPG, similar findings were observed, with signs of material degradation, the presence of granulation tissue along the defect area and newly formed bone into the area of the defect. Additionally, histomorphometry showed that the control group presented higher values for Ob.S/BS (%) and for N.Ob/T.Ar (mm²) (six weeks post-surgery) compared to BS/SPG and higher values of N.Ob/T.Ar (mm²) compared to BS (two weeks post-surgery). Moreover, BS showed higher values for OV/TV (%) compared to BS/SPG (six weeks post-surgery). Also, VEGF immunohistochemistry was increased for BS (two weeks post-surgery) and for BS/SPG (six weeks) compared to CG. TGFb immunostaining was higher for BS compared to CG. The results of this study demonstrated that the BS and BS/SPG scaffolds were biocompatible and able to support bone formation in a critical bone defect in rats. Moreover, an increased VEGF immunostaining was observed in BS/SPG.