Hard and Soft Tissue Evaluation of Different Socket Preservation Procedures Using Leukocyte and Platelet-Rich Fibrin: A Retrospective Clinical and Volumetric Analysis

Platelet-rich fibrin as an autologous biomaterial for bone regeneration: mechanisms, applications, optimization

Platelet-rich fibrin, a classical autologous-derived bioactive material, consists of a fibrin scaffold and its internal loading of growth factors, platelets, and leukocytes, with the gradual degradation of the fibrin scaffold and the slow release of physiological doses of growth factors. PRF promotes vascular regeneration, promotes the proliferation and migration of osteoblast-related cells such as mesenchymal cells, osteoblasts, and osteoclasts while having certain immunomodulatory and anti-bacterial effects. PRF has excellent osteogenic potential and has been widely used in the field of bone tissue engineering and dentistry. However, there are still some limitations of PRF, and the improvement of its biological properties is one of the most important issues to be solved. Therefore, it is often combined with bone tissue engineering scaffolds to enhance its mechanical properties and delay its degradation. In this paper, we present a systematic review of the development of platelet-rich derivatives, the structure and biological properties of PRF, osteogenic mechanisms, applications, and optimization to broaden their clinical applications and provide guidance for their clinical translation.

Minimal invasiveness in the alveolar ridge preservation, with or without concomitant implant placement

The aim of this systematic review was to evaluate the benefit of ridge preservation (RP) with minimally invasive (MI) approaches with or without concomitant implant placement on morbidity, esthetics, and patient-related outcomes. Three Internet sources were used to search for appropriate papers. The search strategy was designed to include any clinical study published on RP with MI approaches such as flapless surgery, socket shield and socket sealing techniques and, use of biological agents. Characteristics of the individual studies, regarding methodological aspects, quantitative and qualitative data were extracted. The potential risk of bias was estimated, and the acquired evidence was graded. Independent screening of 860 reports resulted in 26 included original articles. Nine publications evaluated MI approaches for RP without concomitant implant placement. Eleven studies evaluated interventions for RP with immediate implant placement (IIP). Six studies compared RP with IIP vs RP without IIP. This systematic review found that MI approaches in most of the studies failed to improve clinical variables regarding morbidity, esthetics, and patient-related outcomes. Based on the limited number of studies analyzed and the methodological discrepancies observed, it is not possible to confirm that MI approaches promote a significant benefit when applied to RP procedures.

Regenerative Potential of Platelet Rich Fibrin (PRF) in Socket Preservation in Comparison with Conventional Treatment Modalities: A Systematic Review and Meta-Analysis

BACKGROUND

Platelet rich fibrin (PRF) has shown great potential in osteogenesis; however, some studies still question utilizing it as a grafting material. Thus, the aim of this review is to evaluate the effect of PRF when used in socket and ridge preservation procedures.

METHODS

Electronic searches through MEDLINE, EMBASE, and Cochrane, Science Citation Index Expanded databases and manual searches of unpublished data, academic theses, and journals were conducted up until July 2021. The outcomes were to assess the ability of PRF as a graft material to preserve bone width, height, and density after tooth extraction.

RESULTS

Twelve studies were included in the review, using PRF showed significant results in all three outcomes when compared to no grafting at all, however when compared to other commonly used grafting materials it showed a lesser effect. On the other hand, most studies included reported mixing PRF with a graft material showed the best result. The meta-analysis also revealed the significant results in using PRF on the three outcomes.

CONCLUSION

The meta-analysis of the studies included proved the beneficial effect of PRF in socket preservation surgeries alone or in combination with other graft materials, but further individual multi-centre randomized controlled studies with appropriate sample size are still needed to further confirm our findings.

Influence of Immediate Implant Placement and Provisionalization with or without Soft Tissue Augmentation on Hard and Soft Tissues in the Esthetic Zone: A One-Year Retrospective Study

The purpose of this clinical research was to evaluate peri-implant marginal changes around immediate implants placed either with the application of SCTG or XCM or without soft tissue grafting. A total of 48 patients requiring a single implant-supported restoration in the anterior jaw were selected for inclusion. Three surgical procedures were performed, as follows: type 1 implant with subepithelial connective tissue graft (SCTG), type 1 implant with xenogenic collagen matrix (XCM), and type 1 implant without soft tissue augmentation (NG) (control group). The marginal change of peri-implant soft tissue, facial soft tissue thickness (FSTT), peri-implant health status, esthetics, and patient satisfaction were assessed at one year after surgery. All of the placed implants showed a survival rate of 100%. No significant differences in FSTT were recorded between the SCTG group and the XCM group after treatment (P > 0.05), while the NG group presented a significant difference (P < 0.05). Patients in the NG group lost significantly more in the buccal marginal level than did patients in the SCTG group and those in the XCM group (P < 0.05). The favourable success rate recorded in all groups confirmed immediate tooth replacement as a choice of treatment for a missing anterior single tooth. The NG group presented significant changes of FSTT and buccal marginal level, while XCM constituted a viable alternative to SCTG.

Use of Platelet-Rich Fibrin in the Treatment of Grade 2 Furcation Defects: Systematic Review and Meta-Analysis

In periodontitis patients, furcation defects are crucial sites to regenerate due to their complex anatomy. Various modern surgical techniques and use of biomaterials have been suggested in the literature. Among all, platelet-rich fibrin (PRF) has potential in tissue regeneration thanks to its role in the release of growth factors. Therefore, the purpose of this study was to evaluate the beneficial effect of the addition of PRF to open flap debridement (OFD) or as an adjuvant to other biomaterials such as bone grafts in the treatment of grade 2 mandibular furcation defects. Systematic research was carried out on the databases Medline, Scopus, Embase, and Cochrane Library and registered on PROSPERO (CRD42020167662). According to the PICO guidelines by Cochrane, randomized trials and prospective non-randomized trials were evaluated, with a minimum follow-up period of 6 months. The inclusion criteria were the absence of systemic diseases, non-smoking patients, and a population aged from 18 to 65 years. Vertical pocket probing depth (PPD), vertical clinical attachment level (VCAL), and gingival recession (REC) were the primary outcomes. Vertical furcation depth (VFD), and the percentage of bone defect fill (%v-BDF) were considered as secondary outcomes. A meta-analysis of the primary and secondary outcomes was performed. Publication bias was assessed through a funnel plot. Eighty-four articles were initially extracted. Eight randomized clinical trials were analyzed according to the exclusion and inclusion criteria. The Quality assessment instrument (QAI) revealed four articles at low risk of bias, one at moderate, and three at high risk of bias. The metanalysis showed significant data regarding PPD, VCAL, VFD and %v-BDF in the comparison between PRF + OFD vs. OFD alone. The adjunct of PRF to a bone graft showed a significant difference for VCAL and a not statistically significant result for the other involved parameters. In conclusion, the adjunctive use of PRF to OFD seems to enhance the periodontal regeneration in the treatment of grade 2 furcation defects. The combination of PRF and bone graft did not show better clinical results, except for VCAL, although the amount of literature with low risk of bias is scarce. Further well-designed studies to evaluate the combination of these two materials are therefore needed.

Platelet-Rich Fibrin Can Neutralize Hydrogen Peroxide-Induced Cell Death in Gingival Fibroblasts

Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells were exposed to hydrogen peroxide with and without lysates obtained from PRF membranes, PPP, heated PPP (75 °C for 10 min), and the buffy coat. Cell viability was examined by trypan blue staining, live-dead staining, and formazan crystal formation. Cell apoptosis was assessed by cleaved caspase-3 Western blot analysis. Reverse transcription-quantitative polymerase chain reaction (RT-PCR) was utilized to determine the impact of PRF lysates on the expression of catalase in fibroblasts. It was reported that lysates from PRF, PPP, and the buffy coat—but not heated PPP—abolished the hydrogen peroxide-induced toxicity in gingival fibroblasts. Necrosis was confirmed by a loss of membrane integrity and apoptosis was ruled out by the lack of cleavage of caspase-3. Aminotriazole, an inhibitor of catalase, reduced the cytoprotective activity of PRF lysates yet blocking of glutathione peroxidase by mercaptosuccinate did not show the same effect. PRF lysates had no impact on the expression of catalase in gingival fibroblasts. These findings suggest that PRF, PPP, and the buffy coat can neutralize hydrogen peroxide through the release of heat-sensitive catalase.

Quality of Life of Patients with Mandibular Third Molars and Mild Pericoronitis. A Comparison between Two Different Treatments: Extraction or Periodontal Approach

Background: The extraction of the mandibular third molar is one of the most frequent intervention in oral surgery. A common indication for wisdom tooth extraction is represented by pericoronitis, which can determine discomfort and pain in patients. The present study aimed to evaluate the impact of patients’ quality of life by comparing a surgical approach with a periodontal approach. Methods: We evaluated 82 patients diagnosed with pericoronitis that occurred at the third molar site. In total, 41 of them received a periodontal treatment and 41 were treated by extraction. The quality of life (QoL) of the patients was assessed by using the Oral Health Impact Profile-14 (OHIP-14) index. Results: A total of 82 patients were included in the study and were followed up for 6 months. Of the patients, 41 received a periodontal treatment and 41 underwent surgical extraction. At the baseline, the OHIP-14 scores of the surgical group were higher (19.71, SD 9.90) than the periodontal group (14.41, SD 8.71). At 1 week, there was a reduction in terms of OHIP-14 in both groups, but the periodontal group showed lower values (12.3, SD 8.11). Long-term follow-up showed a reduction of the OHIP-14 values, with a difference in favor of the surgical group (0.10, SD 0.45). However, there was a reduction in OHIP-14 scores in both groups. Conclusion: Although the periodontal treatment offered a rapid improvement in terms of quality of life during the first week after the treatment, after 1 month and 6 months, the extraction of the mandibular third molar extraction remained the best treatment, removing the occurrence of re-inflammation of the site.

The Effectiveness of Chlorhexidine and Air Polishing System in the Treatment of Candida albicans Infected Dental Implants: An Experimental In Vitro Study

Background: Peri-implantitis is an inflammatory disease with an increasing diffusion rate which can affect the long-term survival of a prosthetic rehabilitation. The present study focused on the decontaminating efficacy of chlorhexidine and air polishing system with sodium bicarbonate powder against Candida albicans, a microorganism which seems to have a superinfecting opportunistic role in the pathology. The aim of the authors was to investigate and compare the effectiveness of these treatments, commonly used in clinical practice. Methods: An in vitro study was conducted to analyze the effects of two widely used therapeutic aids for the disinfection of affected titanium implants: chlorhexidine (CHX) and air polishing with sodium bicarbonate powder (P). A qualitative and quantitative comparative analysis of the residual biofilm was carried out using a colorimetric assay (XTT) and scanning electron microscopy (SEM) observation. The experiment was conducted both on machined titanium surfaces and on rough sandblasted ones with the aim of bringing out differences in the therapeutic outcomes concerning the superficial texture of the implant. The null hypothesis was that no difference could be detected between the samples, regarding both the treatments performed and the nano-structural features of titanium. Results: The best results (on both types of implant surfaces) were obtained when combining the use of chlorhexidine and air polishing (C + P). A linear decrease in the optical density (OD) values recorded at three different time points (30 s, 1 min, 5 min) was also observed passing from the first to the last one. When observed under scanning electron microscope rough surfaces showed an extensive and highly structured biofilm, more complex if compared to the one encountered when analyzing machined implants. Conclusions: the present pilot study showed that rough surfaces can promote fungal adhesion and eventually hinder the outcome of a decontaminating treatment. For this purpose, the physio-chemical technique is always more efficient if compared to a single-technique approach regardless of the surface characteristics.

The Use of a Non-Absorbable Membrane as an Occlusive Barrier for Alveolar Ridge Preservation: A One Year Follow-Up Prospective Cohort Study

：The aims of this study were to obtain preliminary data and test the clinical efficacy of a novel nonporous dense-polytetrafluoroethylene (d-PTFE) membrane (permamem®, botiss) in alveolar ridge preservation (ARP) procedures with a flapless approach. A traumatic extraction was performed in the premolar maxillary area, and a d-PTFE membrane was used to seal the alveolar cavity: no biomaterial was used to graft the socket and the membrane was left intentionally exposed and stabilized with sutures. The membrane was removed after four weeks and dental implants were placed four months after the procedure. The primary outcome variables were defined as the dimensional changes in the ridge width and height after four months. A total of 15 patients were enrolled in this study. The mean width of the alveolar cavity was 8.9 ± 1.1 mm immediately after tooth extraction, while four months later a mean reduction of 1.75 mm was experienced. A mean vertical reduction of 0.9 ± 0.42 mm on the buccal aspect and 0.6 ± 0.23 mm on the palatal aspect were recorded at implant placement. Within the limitations of this study, the d-PTFE membrane proved to be effective in alveolar ridge preservation, with the outcomes of the regeneration not affected by the complete exposure of this biomaterial.

Molecular and Cellular Aspects of Socket Healing in the Absence and Presence of Graft Materials and Autologous Platelet Concentrates: a Focused Review

OBJECTIVES

The present manuscript aims to critically detail the physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates, addressing the associated molecular and cellular events that culminate in the restoration of the lost tissue architecture and functionality.

MATERIAL AND METHODS

An electronic search in the National Library of Medicine database MEDLINE through its online site PubMed and Web of Science from inception until May 2019 was conducted to identify articles concerning physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates. The search was restricted to English language articles without time restriction. Additionally, a hand search was carried out in oral surgery, periodontology and dental implants related journals.

RESULTS

In total, 122 literature sources were obtained and reviewed. The detailed biological events, at the molecular and cellular level, that occur in the alveolus after tooth extraction and socket healing process modulated by grafting materials or autologous platelet concentrates were presented as two entities.

CONCLUSIONS

Tooth extraction initiates a convoluted set of orderly biological events in the alveolus, aiming wound closure and socket healing. The healing process comprises a wide range of events, regulated by the interplay of cytokines, chemokines and growth factors that determine cellular recruitment, proliferation and differentiation in the healing milieu, in a space- and time-dependent choreographic interplay. Additionally, the healing process may further be modulated by the implantation of grafting materials or autologous platelet concentrates within the tooth socket, aiming to enhance the regenerative outcome.