Dimensional and histomorphometric evaluation of biomaterials used for alveolar ridge preservation: a systematic review and network meta-analysis

Learn, unlearn, and relearn post-extraction alveolar socket healing: Evolving knowledge and practices

OBJECTIVE

This review was to offer a comprehensive analysis of currently available evidence on post-extraction alveolar socket healing, including i) the histological and molecular events during alveolar socket healing, ii) the dimensional ridge alterations after socket healing and controversies relating to sinus pneumatisation, iii) the patient-specific factors, procedural elements, and site-related variables influencing socket healing, iv) techniques and effectiveness of alveolar ridge preservation (ARP) procedure, and v) the philosophies and cost-effectiveness of ARP in clinical practice.

SOURCES AND STUDY SELECTION

To investigate the dimensional profiles of the alveolar ridge following unassisted healing, an overview of systematic reviews was conducted in February 2024 by two independent reviewers. Four electronic databases were searched in Pubmed, Embase, Web of science and Cochrane Library between 2004 and 2024 to identify all relevant systematic reviews on post-extraction healing. A further manual search of reviews was also conducted. The articles were further reviewed in full text for relevance. The AMSTAR-2 appraisal tool was adopted to assess methodological quality. Current research pertaining to other listed objectives was objectively analysed in narration.

DATA

11 out of 459 retrieved studies were selected and ultimately covered in this review on the dimensional changes of alveolar ridge following natural healing: Seven systematic reviews and four systematic reviews with meta-analyses. The methodological quality of all included reviews was critically low.

CONCLUSION

This review thoroughly examines the healing profiles of post-extraction alveolar sockets and highlights the dynamic process with overlapping phases and the inter-individual variability in outcomes. ARP procedure is a potential strategy for facilitating prosthetic site development, while the current evidence is limited. Herein, an individualised and prosthetically driven approach is crucial. Further well sized and designed trials with novel biomaterials need to be undertaken, and the role of artificial intelligence in predicting healing and assisting clinical decision-making could be explored.

CLINICAL SIGNIFICANCE

By advancing our understanding of alveolar socket healing and its management strategies, clinicians can make more informed decisions regarding patient and site level assessment and selection, surgical techniques, and biomaterial choices, ultimately contributing to the enhanced healing process with reduced complications and improved quality of life for patients undergoing tooth extraction and dental implant treatments.

Efficacy and safety of a new heterologous fibrin biopolymer on socket bone healing after tooth extraction: An experimental pre-clinical study

AIM

To assess the efficacy of heterologous fibrin biopolymer (HFB) in promoting alveolar bone healing after tooth extraction in rats.

MATERIALS AND METHODS

The upper right incisors of 48 Wistar rats were extracted. Toothless sockets were filled with HFB (HFBG, n = 24) or blood clot (BCG, n = 24). The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric and immunohistochemical (for Runt-related transcription factor 2/Runx2 and tartrate-resistant acid phosphatase/TRAP) analyses on days 0, 7, 14 and 42 after extraction.

RESULTS

Socket volume remained similar between days 0 and 14 (69 ± 5.4 mm3), except in the BCG on day 14, when it was 10% lower (p = .043). Although the number of Runx2+ osteoblasts was high and similar in both groups (34 × 102 cells/mm2), the HFBG showed lower inflammatory process and osteoclast activity than BCG at 7 days. On day 14, the number of Runx2+ osteoblasts remained high and similar to the previous period in both groups. However, osteoclast activity increased. This increase was 55% lower in the HFBG than BCG. In the BCG, the presence of an inflammatory process and larger and numerous osteoclasts on day 14 led to resorption of the alveolar bone ridge and newly formed bone. On day 42, numbers of Runx2+ osteoblast and TRAP+ osteoclasts decreased dramatically in both groups. Although the BCG exhibited a more mature cortical bone formation, it exhibited a higher socket reduction (28.3 ± 6.67%) and smaller bone volume (37 ± 5.8 mm3) compared with HFBG (socket reduction of 14.8 ± 7.14% and total bone volume of 46 ± 5.4 mm3).

CONCLUSIONS

HFB effectively suppresses osteoclast activity and reduces alveolar bone resorption compared with blood clot, thus preventing three-dimensional bone loss, particularly during the early healing period. HFB emerges as a promising biopharmaceutical material for enhancing healing processes after tooth extraction.

Single missing molar with wide mesiodistal length restored using a single or double implant-supported crown: A self-controlled case report and 3D finite element analysis

PURPOSE

Based on a self-controlled case, this study evaluated the finite element analysis (FEA) results of a single missing molar with wide mesiodistal length (MDL) restored by a single or double implant-supported crown.

METHODS

A case of a missing bilateral mandibular first molar with wide MDL was restored using a single or double implant-supported crown. The implant survival and peri-implant bone were compared. FEA was conducted in coordination with the case using eight models with different MDLs (12, 13, 14, and 15 mm). Von Mises stress was calculated in the FEA to evaluate the biomechanical responses of the implants under increasing vertical and lateral loading, including the stress values of the implant, abutment, screw, crown, and cortical bone.

RESULTS

The restorations on the left and right sides supported by double implants have been used for 6 and 12 years, respectively, and so far have shown excellent osseointegration radiographically.The von Mises stress calculated in the FEA showed that when the MDL was >14 mm, both the bone and prosthetic components bore more stress in the single implant-supported strategy. The strength was 188.62-201.37 MPa and 201.85-215.9 MPa when the MDL was 14 mm and 15 mm, respectively, which significantly exceeded the allowable yield stress (180 MPa).

CONCLUSIONS

Compared with the single implant-supported crown, the double implant-supported crown reduced peri-implant bone stress and produced a more appropriate stress transfer model at the implant-bone interface when the MDL of the single missing molar was ≥14 mm.

Half- and full-grafting alveolar ridge preservation with different sealing materials: A three-arm randomized clinical trial

OBJECTIVE

The objective of this study is to investigate the effect of different alveolar ridge preservation (ARP) approaches on bone resorption and their potential for facilitating implant placement.

MATERIALS AND METHODS

Patients who underwent one or two tooth extractions with a desire for restoration were included in the study. The participants were randomly assigned to one of three groups for ARP. The groups were as follows: (1) Half grafting of bovine bone mineral (DBBM-C) covered with non-resorbable dense polytetrafluoroethylene (dPTFE) membrane (Test 1 group); (2) Half grafting of bovine bone mineral (DBBM-C) covered with collagen membrane (Test 2 group); and (3) Full grafting with collagen membrane (DBBM-C + Collagen membrane) as the Control group. After 6-month healing period, the evaluation encompassed clinical, radiographic, implant-related outcomes, and the factors contributing to hard and soft tissue alterations.

RESULTS

Enrollment in this study comprised 56 patients. At the 6-month follow-up, radiographic analysis in computed beam computed tomography images was conducted for 18, 19, and 19 patients with 18, 20, and 20 tooth sites in Test 1, Test 2, and Control groups, respectively. Additionally, a total of 15, 17, and 17 patients with 15, 18, and 17 implants were evaluated. Based on radiographic analysis, all groups showed limited ridge resorption at 1 mm from crest horizontally (Test 1: 1.29 ± 1.37; Test 2: 1.07 ± 1.07; Control: 1.54 ± 1.33 mm, p = 0.328), while the Control group showed greater radiographic bone height gain in mid-crestal part vertically (Test 1: 0.11 ± 1.02; Test 2: 0.29 ± 0.83; Control: -0.46 ± 0.95 mm, p = 0.032). There were no significant intergroup differences in terms of keratinized mucosal width, bone density, insertion torque, and the need of additional bone graft. However, the use of a dPTFE membrane resulted in a significantly higher vertical mucosal thickness (Test 1: 2.67 ± 0.90; Test 2: 3.89 ± 1.08; Control: 2.41 ± 0.51 mm, p < 0.001).

CONCLUSIONS

The study showed comparable dimensional preservation with limited vertical shrinkage, while thin buccal bone plate, non-molar sites, and large discrepancy between buccal and palatal/lingual height may contribute to greater shrinkage. Thicker mucosa with dPTFE membrane required further investigation for interpretation.

CLINICAL TRIAL REGISTRATION NUMBER

NCT06049823. This clinical trial was not registered prior to participant recruitment and randomization.

Effect of buccal fat autotransplantation on improving the alveolar socket bone regeneration: An in-vivo study

Background

There are various materials used for socket preservation following dental extraction. The aim of the present animal study was to histologically investigate the efficacy of buccal fat autotransplantation on alveolar bone regeneration following dental extraction.

Study design

In this prospective, double-blind laboratory experiment with a split-mouth design, 16 mandibular second premolar teeth in eight beagle dogs were extracted, and half of the extraction sockets were randomly filled using buccal fat autotransplantation. Other samples were left untouched to heal normally by the formed blood clot. Buccal fat autotransplantation was the primary predictor variable, and the type and amount of newly formed bone were the primary outcome variables. Assessment methods were the H & E coloring technique and histomorphometric evaluation. The significance level was set at 0.05, and data was subjected to Chi-Square and Wilcoxon signed-rank tests using SAS statistical software version 9.4.

Results

From the total number of 16 samples in 8 dogs, 50% of the samples in the intervention group represented inflammation with lower intensity compared to 33% in the control group; however, this difference was not considered statistically significant (Chi-Square test, P-value = 0.55). Wilcoxon test results showed no statistically significant difference between the two groups regarding the mean amount of total bone formation (Z = 0.00, P-value = 1.00).

Conclusion

It was inferred from the outcomes of the present study that when compared to the normal healing of the socket, buccal fat autotransplantation did not represent with superior outcome concerning the socket bone regeneration.

Efficacy of Alveolar Ridge Preservation in Periodontally Compromised Molar Extraction Sites: A Systematic Review and Meta-Analysis

AIM

To investigate the efficacy of alveolar ridge preservation (ARP) in periodontally compromised molar extraction sites.

METHODS

An electronic search was performed on 10th November 2023 across five databases, seeking randomised/non-randomised controlled trials (RCTs/NCTs) that included a minimum follow-up duration of four months. The RoB2 and Robins-I tools assessed the risk of bias for the included studies. Data on alveolar ridge dimensional and volumetric changes, keratinized mucosal width, and need for additional bone augmentation for implant placement were collected. Subsequently, a meta-analysis was carried out to derive the pooled estimates.

RESULTS

Six studies were incorporated in the present review, and a total of 135 molar extraction sockets in 130 subjects were included in the meta-analysis. ARP was undertaken in 68 sites, and 67 sites healed spontaneously. The follow-up time ranged from 4 to 6 months. The meta-analysis of both RCTs and NCTs showed significant differences in mid-buccal ridge width changes at 1 mm level below ridge crest with a mean difference (MD) of 3.80 (95% CI: 1.67-5.94), mid-buccal ridge height changes (MD: 2.18; 95% CI: 1.25-3.12) and volumetric changes (MD: 263.59; 95% CI: 138.44-388.74) in favour of ARP, while the certainty of evidence is graded low to very low. Moreover, ARP appeared to reduce the need for additional sinus and bone augmentation procedures at implant placement with low certainty of evidence.

CONCLUSIONS

Within the limitations of this study, alveolar ridge preservation in periodontally compromised extraction sites may, to some extent, preserve the ridge vertically and horizontally with reference to spontaneous healing. However, it could not eliminate the need for additional augmentation for implant placement. Further, longitudinal studies with large sample sizes and refined protocols are needed.

The Added Value of a Collagenated Thermosensitive Bone Substitute as a Scaffold for Bone Regeneration

A pre-hydrated thermosensitive collagenated biomaterial which sets at body temperature and maintains the space of the missing alveolar bone volume, OsteoBiol GTO® (GTO), has been released as a bone substitute. This study was designed to check its angiogenic and osteogenic potentials compared to OsteoBiol Gen-Os® (Gen-Os) and Geistlich Bio-Oss® (Bio-Oss). Samples of materials were incubated in culture media to obtain the extracts. Collagen release was measured in the extracts, which were used to investigate human periodontal ligament (hPDL) cell proliferation (MTT), colonization (Scratch assays) and growth factor release (ELISA). The effects on endothelial cell proliferation (MTT) and organization (Matrigel® assays) were also studied. Finally, endothelial and mesenchymal Stem Cell (hMSC) recruitment (Boyden Chambers) were investigated, and hMSC Alkaline Phosphatase (ALP) activity was measured. A higher collagen concentration was found in GTO extract, which led to significantly higher hPDL cell proliferation/colonization. All materials increased VEGF/FGF-2 growth factor secretion, endothelial cell recruitment, proliferation, and organization, but the increase was highest with GTO. All materials increased hMSC recruitment and ALP activity. However, the increase was highest with collagenated GTO and Gen-Os, which enhanced C5a and BMP-2 secretion. Overall, GTO has higher angiogenic/osteogenic potentials than the collagenated Gen-Os and the anorganic Bio-Oss. It provides a suitable scaffold for endothelial and mesenchymal stem cell recruitment, which represent essential bone regeneration requirements.

Hyaluronic Acid Treatment of Post-Extraction Tooth Socket Healing in Subjects with Diabetes Mellitus Type 2: A Randomized Split-Mouth Controlled Study

The present study aimed to investigate the effect of HA in improving post-extraction socket healing in subjects with diabetes mellitus (DM) type 2. DM patients requiring bilateral extraction of the homologous teeth were visited at the C.I.R. Dental School, University of Turin. After the extractions, one site was randomly assigned to the test (T) group (postoperative application of HA), while the other site was assigned to the control group (C, no treatment). Patients were then followed after 3, 7, 14, and 21 days. Primary outcomes were the healing index and socket closure. The Mann-Whitney test or the Student's t-test was used for nonparametric or parametric distributed variables. The chi-square test was used if the estimated data in any given cell were >5, otherwise the Fisher test was adopted. A p < 0.05 was considered statistically significant. In total, 36 patients (n = 36) were enrolled in this study for a total of 72 extractions (n = 72). Sockets treated with HA showed significantly (p < 0.05) better healing index values at day 7 (p = 0.01) and at day 14 (p = 0.02) and significantly (p < 0.05) better socket closure values at day 3 (p = 0.04), day 7 (p = 0.001) and day 14 (p = 0.001) compared to the C group. Based on the clinical results, HA seems to be promising in improving the timing and the quality of post-extractive wound healing in DM patients. Further clinical research, as well as histological investigations, are required to confirm the results.

Prevalence of peri-implantitis after alveolar ridge preservation at periodontitis and nonperiodontitis extraction sites: A retrospective cohort study

INTRODUCTION

Periodontitis is the main indication for dental extraction and often leads to peri-implantitis (PI). Alveolar ridge preservation (ARP) is an effective means of preserving ridge dimensions after extraction. However, whether PI prevalence is lower after ARP for extraction after periodontitis remains unclear. This study investigated PI after ARP in patients with periodontitis.

MATERIALS AND METHODS

This study explored the 138 dental implants of 113 patients. The reasons for extraction were categorized as periodontitis or nonperiodontitis. All implants were placed at sites treated using ARP. PI was diagnosed on the basis of radiographic bone loss of ≥3 mm, as determined through comparison of standardized bitewing radiographs obtained immediately after insertion with those obtained after at least 6 months. Chi-square and two-sample t testing and generalized estimating equations (GEE) logistic regression model were employed to identify risk factors for PI. Statistical significance was indicated by p < 0.05.

RESULTS

The overall PI prevalence was 24.6% (n = 34). The GEE univariate logistic regression demonstrated that implant sites and implant types were significantly associated with PI (premolar vs. molar: crude odds ratios [OR] = 5.27, 95% confidence intervals [CI] = 2.15-12.87, p = 0.0003; bone level vs. tissue level: crude OR = 5.08, 95% CI = 2.10-12.24; p = 0.003, respectively). After adjustment for confounding factors, the risks of PI were significantly associated with implant sites (premolar vs. molar: adjusted OR [AOR] = 4.62, 95% CI = 1.74-12.24; p = 0.002) and implant types (bone level vs. tissue level: AOR = 6.46, 95% CI = 1.67-25.02; p = 0.007). The reason for dental extraction-that is, periodontitis or nonperiodontitis-was not significantly associated with PI.

CONCLUSION

ARP reduces the incidence of periodontitis-related PI at extraction sites. To address the limitations of our study, consistent and prospective randomized controlled trials are warranted.

Surface demineralized freeze-dried bone allograft followed by reimplantation in a failed mandibular dental implant

The removal of a failed implant with high torque causes significant damage to the surrounding tissue, compromising bone regeneration and subsequent osseointegration in the defect area. Here, we report a case of carrier screw fracture followed by immediate implant removal, bone grafting and delayed reimplantation. A dental implant with a fractured central carrier screw was removed using the bur-forceps technique. The resulting three-wall bone defect was filled with granular surface demineralized freeze-dried bone allograft (SD-FDBA). Cone-beam computerized tomography was performed at 1 week, 6 months and 15 months postoperatively and standardized for quantitative evaluation. The alveolar bone width and height at 15 months post-surgery were about 91% of the original values, with a slightly lower bone density, calculated using the gray value ratio. The graft site was reopened and was found to be completely healed with dense and vascularized bone along with some residual bone graft. Reimplantation followed by restoration was performed 8 months later. The quality of regenerated bone following SD-FDBA grafting was adequate for osseointegration and long-term implant success. The excellent osteogenic properties of SD-FDBA are attributed to its human origin, cortical bone-like structure, partly demineralized surfaces and bone morphogenetic protein-2-containing nature. Further investigation with more cases and longer follow-up was required to confirm the final clinical effect.

Demineralized dentin matrix promotes gingival healing in alveolar ridge preservation of premolars extracted for orthodontic reason: a split-mouth study

Objective

The purpose of this study was to prospectively evaluate the efficacy of a demineralized dentin matrix (DDM) in decreasing the initial inflammatory response of the gingiva and facilitating the repair and regeneration of soft tissue in alveolar ridge preservation.

Methods

This clinical study employed a split-mouth design. Fourteen patients with a total of forty-four sites underwent extraction and alveolar ridge preservation (ARP) procedures. A Bilaterally symmetrical extraction operation were conducted on the premolars of each patient. The experimental group received DDM as a graft material for ARP, while the control group underwent natural healing. Within the first month postoperatively, the pain condition, color, and swelling status of the extraction sites were initially assessed at different time points Subsequently, measurements were taken for buccal gingival margin height, buccal-lingual width, extraction socket contour, and the extraction socket area and healing rate were digitally measured. Additionally, Alcian Blue staining was used for histological evaluation of the content during alveolar socket healing.

Results

Both groups experienced uneventful healing, with no adverse reactions observed at any of the extraction sites. The differences in VAS pain scores between the two groups postoperatively were not statistically significant. In the early stage of gingival tissue healing (3 days postoperatively), there were statistically significant differences in gingival condition and buccal gingival margin height between the two groups. In the later stage of gingival tissue healing (7, 14, and 30 days postoperatively), there were statistically significant differences in buccal-lingual width, extraction socket healing area, and healing rate between the two groups. Furthermore, the histological results from Alcian Blue staining suggested that the experimental group may play a significant role in promoting gingival tissue healing, possibly by regulating inflammatory responses when compared to the control group.

Conclusion

The application of DDM in alveolar ridge preservation has been found to diminish initial gingival inflammation after tooth extraction. Additionally, it has shown the ability to accelerate early gingival soft tissue healing and preserve its anatomical contour.

Clinical trial registration

chictr.org.cn, identifier ChiCTR2100050650.

Current Knowledge on the Healing of the Extraction Socket: A Narrative Review

The concept of extraction socket healing has been severally researched and reported over the years, since tooth extraction remains one of the most common procedures performed in the dental clinic. Understanding this healing process is of utmost importance because the outcome has a direct bearing on future prosthetic rehabilitation and, by extension, on patients' esthetics and masticatory function, among others. This mini review, therefore, summarized the current knowledge on the different stages of socket healing, including the biologic and clinical events that occur following tooth extraction up until the complete closure of the socket. Additionally, the modeling of the alveolar bone/process post extraction, and the resultant dimensional changes that, altogether, shape the bone, were reviewed and documented. The effects of various socket preservation interventions to mitigate these dimensional changes, and therefore preserve the alveolar process in a condition suitable for future prosthetic rehabilitation, were highlighted. Finally, a review of some of the factors that influence the entire process was also carried out.

Research Hotspots and Trends of Bone Xenograft in Clinical Procedures: A Bibliometric and Visual Analysis of the Past Decade

BACKGROUND

Bone defect therapy is a common clinical challenge for orthopedic and clinical physicians worldwide, and the therapeutic effect affects the physiological function and healthy life quality of millions of patients. Compared with traditional autogenous bone transplants, bone xenografts are attracting attention due to their advantages of unlimited availability and avoidance of secondary damage. However, there is currently a lack of bibliometric analysis on bone xenograft. This study aimed to use bibliometric methods to analyze the literature on bone xenograft from 2013 to 2023, to explore the current status, hotspots, and future trends of research in this field, and to promote its development and progress.

METHODS

Using the Web of Science Core Collection database, we retrieved and collected publication data related to xenogeneic bone grafting materials worldwide from January 2013 to March 2023. Origin (2021), CiteSpace (6.2.R2 standard), and an online bibliometric platform were used for bibliometric analysis and data visualization.

RESULTS

A total of 3395 documents were retrieved, and 686 eligible papers were selected. The country and institutions with the highest number of publications and centrality were the United States (125 papers, centrality = 0.44) and the University of Zurich (29 papers, centrality = 0.28), respectively. The most cited author was Araujo MG (163 times), and the author with the most significant centrality was Froum SJ (centrality = 0.09). The main keyword clusters were "tissue engineering", "sinus floor elevation", "dental implants", "tooth extraction", and "bone substitutes". The most significant bursting keywords in the last three years were "platelet rich fibrin".

CONCLUSIONS

Research on bone xenograft is steadily growing and will continue to rise. Currently, research hotspots and directions are mainly focused on dental implants related to bone-augmentation techniques and bone tissue engineering. In the future, research hotspots and directions may focus on decellularization technology and investigations involving platelet-rich fibrin.

Effect of the use of platelet concentrates on new bone formation in alveolar ridge preservation: a systematic review, meta-analysis, and trial sequential analysis

OBJECTIVES

To investigate the histomorphometric changes occurring in alveolar ridge preservation (ARP) based on the use of different plasma concentrates (PCs) in randomized clinical trials (RCT). There is controversy whether the placement of PCs in ARP is effective in the formation of new bone.

MATERIALS AND METHODS

A systematic review search was conducted in PubMed, Scopus, Web of Science, and Cochrane Database to answer the PICO question: In patients undergoing tooth extraction followed by ARP, do PCs alone in the post-extraction socket in comparison with spontaneous healing improve new vital bone formation percentage in histomorphometric analysis after more than 10 weeks? The risk of bias was assessed and a meta-analysis was conducted.

RESULTS

Of 3809 results, 8 studies were considered suitable for inclusion. A total of 255 teeth were extracted in 250 patients. Regarding the PCs used, ARP was performed with platelet- and leukocyte-rich fibrin (L-PRF) in 120 sockets, and with pure platelet-rich plasma (P-PRP) in 31 sockets and 104 sockets were controlled. PCs improved new bone formation in ARP with respect to the spontaneous healing group (SMD = 1.77, 95%C.I. = 1.47-2.06, p-value < 000.1). There were no differences between the different PCs (L-PRF and P-PRP).

CONCLUSION

The results of this meta-analysis support the efficacy of the use of PCs in new bone formation in ARP. With respect to the different types of PCs studied, no differences were observed.

CLINICAL RELEVANCE

When planning implant surgery after tooth extraction, treatment with PCs should be considered for ARP. Any PC increases new bone formation compared to spontaneous healing.

Evaluation between Biodegradable Magnesium Metal GBR Membrane and Bovine Graft with or without Hyaluronate

Bone substitutes and barrier membranes are widely used in dental regeneration procedures. New materials are constantly being developed to provide the most optimal surgical outcomes. One of these developments is the addition of hyaluronate (HA) to the bovine bone graft, which has beneficial wound healing and handling properties. However, an acidic environment that is potentially produced by the HA is known to increase the degradation of magnesium metal. The aim of this study was to evaluate the potential risk for the addition of HA to the bovine bone graft on the degradation rate and hence the efficacy of a new biodegradable magnesium metal GBR membrane. pH and conductivity measurements were made in vitro for samples placed in phosphate-buffered solutions. These in vitro tests showed that the combination of the bovine graft with HA resulted in an alkaline environment for the concentrations that were used. The combination was also tested in a clinical setting. The use of the magnesium metal membrane in combination with the tested grafting materials achieved successful treatment in these patients and no adverse effects were observed in vivo for regenerative treatments with or without HA. Magnesium based biodegradable GBR membranes can be safely used in combination with bovine graft with or without hyaluronate.

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The Effect of Terra-Cortril as Local Pain Medication on the Healing Process of a Fresh Extraction Socket: A Retrospective Cohort Study

(1) Background: Use of Terra-Cortril may reduce pain and discomfort after tooth extraction. It is widely used among dentists, especially for third molar extraction and for treatment of dry socket. Only few case reports described unsuccessful healing with formation of myospherulosis. (2) Aim: The primary objective of this retrospective cohort study was to compare the occurrence of unsuccessful healing between extraction sockets locally treated with Terra-Cortril (TC) (exposure cohort) and extraction sockets subjected to unassisted healing (non-exposure cohort). The assessment of the three-dimensional morphology of the bone was a secondary objective. (3) Material and methods: The records of patients who had one or more extractions between 1 January 2020 and 1 July 2021 followed by implant placement in one private practice were retrieved and data were extracted. At the time of implant placement, practitioners established, both clinically and radiographically, if the healing was successful or unsuccessful. Explanatory demographic as well as clinical variables were extracted from patient files, checked and supplemented by contacting patients in cases of missing data. (4) Results: 69 patients were included who had, in total, 99 extractions. The exposure cohort included 55 sites, while the non-exposure cohort included 44 sites. A total of 56 sites demonstrated successful healing, and 53 showed unsuccessful healing. The regression model identified TC as a significant predictor (p = 0.014) for unsuccessful healing with an odds ratio of 2.86. Sites treated with Terra-Cortril had a significantly greater bone defect at level -1 mm, level -3 mm, and level -5 mm from the bone crest, and significantly greater maximal vertical and horizontal bone defects. At sites where Terra-Cortril was used, significantly more surgical consequences were reported (70.91% vs. 18.18%, p < 0.001). (5) Conclusions: fresh extraction sockets treated with Terra-Cortril increased the likelihood of unsuccessful healing with an odds ratio of 2.86. The greater defect size leads to significantly more limitations when planning implants at sites previously treated with TC.

An Analysis of Different Techniques Used to Seal Post-Extractive Sites—A Preliminary Report

Background: Bone grafting in post-extractive site improves tissue regeneration. Soft tissue sealing of the grafted post-extractive alveolus is supposed to limit microbiological contamination from the oral cavity and to stabilize the coagulum. Several techniques are presented in the literature to reach this goal using different heterologous matrices or autogenous grafts. In addition, recently, a technique based on the use of granulation tissue in the post-extractive alveolus has been proposed. Aim: To compare the effect of different graft sealing approaches in post-extractive sites by qualitatively evaluating their healing process. Materials and Methods: This retrospective investigation included 30 patients requiring post-extractive site regeneration in the aesthetic area. Post-extractive sites were regenerated using a bovine bone matrix and patients were divided into three groups (10 patients in each group) according to the material used to seal the alveolar socket. In the UD group, the granulation tissue was used to seal the defect; in the PC group, epithelial-connective soft tissue graft was used, and in the COLL group, a collagen-based membrane was employed. Images of the post-extractive sites at different follow-up periods (2 and 12 weeks) were taken and the healing process was blindly evaluated by two independent practitioners. The Healing Index (HI) by Landry, Turnbull and Howley was used to assess the quality of the healing process. The combination of presence/absence of five clinical criteria defines an HI ranging from 1 (very poor) to 5 (excellent). Patients’ clinical-pathological variables were recorded. One-way ANOVA was used to explore the dependence of HI on the different socket preservation protocols. Results: Based on clinical-pathological characteristics of the included patients, there were no statistically significant differences among the different sealing techniques. At the 2-week follow-up appointment, HI did not differ among the socket preservation protocols evaluated. Moreover, smoking status and reason for extraction did not influence the HI among the three groups (two-way ANOVA p-value = 0.686, p-value = 0.248 respectively). At the 2-week follow-up appointment, HI was significantly different among the socket preservation protocols investigated. Specifically, the group undergoing collagen-based socket preservation procedure reported the highest HI, compared to the other two techniques (COLL mean 4.60 ± 0.5; PC mean 3.5 ± 1.2; UD mean 3.4 ± 0.5, one-way ANOVA p-value 0.006). Conclusions: The use of collagen porcine membranes may represent a suitable option to improve the patient healing process in grafted post-extractive sites together with reducing the surgical intervention time compared to alternative sealing techniques.

Characterizations of alveolar repair after mandibular second molar extraction: an experimental study in rats

BACKGROUND

Characterizations of rat mandibular second molar extraction socket with significantly different buccal and lingual alveolar ridge width remain unclear.

OBJECTIVE

To observe alterations in the alveolar ridge after extraction of mandibular second molars, and to examine processes of alveolar socket healing in an experimental model of alveolar ridge absorption and preservation.

METHODOLOGY

Eighteen Wistar rats were included and divided into six groups regarding healing time in the study. Bilateral mandibular second molars were extracted. The rats with tooth extraction sockets took 0, 1.5, 2, 3, 4 and 8 weeks of healing. Histological observation, tartrate-resistant acidic phosphatase (TRAP) staining, Masson's trichrome staining, immunohistochemical staining and micro-computed tomography (micro-CT) were applied to estimate alterations in the alveolar ridge.

RESULTS

Different buccal and lingual alveolar ridge width led to different height loss. Lingual wall height (LH) decreased significantly two weeks after tooth extraction. Buccal wall height rarely reduced its higher ridge width. From two to eight weeks after extraction, bone volume (BV/TV), density (BMD), and trabecular thickness (Tb.Th) progressively increased in the alveolar socket, which gradually decreased in Tb.Sp and Tb.N. LH showed no significant change during the same period. Osteogenic marker OCN and OPN increased during bone repair from two to eight weeks. The reduced height of the lingual wall of the tooth extraction socket was rarely repaired in the later repair stage. Osteoclast activity led to absorption of the alveolar ridge of the alveolar bone wall within two weeks after operation. We observed positive expression of EMMPRIN and MMP-9 in osteoclasts that participated in the absorption of the spire region.

CONCLUSION

Extraction of rat mandibular second molars may help the study of alveolar ridge absorption and preservation. The EMMPRIN-MMP-9 pathway may be a candidate for further study on attenuating bone resorption after tooth extraction.