Healing Of Extraction Sockets Research Articles

Cone Beam Computed Tomography Evaluation of Socket Healing After Third Molar Germ Extraction: A Case Series Study Including Adolescents with Osteogenesis Imperfecta Type I Treated with Bisphosphonates and Healthy Age-Matched Subjects

Bisphophonates (BPs) are widely used in Osteogenesis imperfecta (OI). Cone Beam Computed Tomography (CBCT) shows clinical usefulness in evaluating impacted teeth and adjacent structure relationships, extraction socket healing, bone mineral density (BMD) and BP-related jaw osteonecrosis (BRONJ). The aim of the study was to compare alveolar sockets and the adjacent bone area before and after third molar extraction in OI type I (OI-I) adolescents treated with BPs and age-matched healthy subjects (HSs) by CBCT. Methods: Five adolescents with genetically proven OI-I treated with BPs (three males and two females, mean age: 15.2 ± 1.78 years) and four age-matched healthy subjects (two males and two females, mean age: 15.5 ± 1.29 years) were included in this study. Eight Regions of Interest (ROIs) were evaluated: between 3.7 and 3.8 (ROI-1) and 4.7 and 4.8 (ROI-2); after 3.8 (ROI-3) and 4.8 (ROI-4); alveolar sockets 3.8 (ROI-5) and 4.8 (ROI-6); left (ROI-7) and right (ROI-8) cortical bone. Results: ROIs were evaluated on both sides of the mandible for all the subjects except one OI patient in which CBCTs were performed pre- and-post third molar extraction only on the right side. CBCT was performed 12.8 ± 4.60 and 11.5 ± 2.51 days before and 8.0 ± 1.41 and 7.7 ± 0.5 months after extraction in OI-I and HSs, respectively. BPs were discontinued 62.0 ± 36.5 months before extraction. None of the OI-I adolescents developed BRONJ. Statistically significant greater values were observed in OI-I for ROI-1 and -2 (p = 0.0464), ROI-3 and -4 (p = 0.0037) and ROI-7 and -8 (p = 0.0079) after extraction. Conclusions: This descriptive study confirms that, in OI-I adolescents treated with BPs, third molar extraction is safe, and socket healing occurs properly. In addition, it demonstrates that, if the same device and imaging conditions are used and comparisons to predetermined standard values are avoided, CBCT can be used to monitor BMD changes. The significant greater BMD observed for different ROIs in OI-I could reflect the increased secondary mineralization related to the BP-dependent reduction in bone turnover.

Comparative Study of Photobiomodulation Effects on Alveolar Socket Hard Tissue Healing in Rats: Application of 980 nm Versus 810 nm Lasers.

Background: This study aimed to explore the differential effects of photobiomodulation (PBM) via 980 nm and 810 nm lasers on the hard tissue healing of rat alveolar sockets, with a focus on a comparative analysis of hard tissue regeneration and osteogenic gene expression. Objective: This study aimed to explore the effects of PBM using 980 nm and 810 nm lasers on hard tissue healing of rat alveolar sockets, focusing on hard tissue regeneration and osteogenic gene expression. Materials and Methods: Thirty-six male Wistar rats (5 weeks old) had both right and left maxillary first molars extracted. Post extraction, the right alveolar sockets received PBM treatment with either 980 nm (0.3 W, 18 J/cm2) or 810 nm (0.1 W, 6 J/cm2) lasers for seven days, whereas the left sockets served as controls. Rats were euthanized on days 3, 7, 14, and 28 for histopathological, immunohistochemical, micro computed tomography (micro-CT), and quantitative polymerase chain reactionanalyses. Results: On day 3, early granulation tissue, neovascularization, and inflammatory cell aggregates were observed in all groups. By day 7, active osteoclasts and osteoblasts were noted, with a significant increase in CD31-positive cells in the 980 nm group (p < 0.05). Day 14 showed new bone formation, and by day 28, increased cancellous bone and collagen content were present in all groups, with no significant differences between them (p > 0.05). Gene expression analysis revealed higher BMP-2 and Runx-2 levels in laser-treated groups on day 14 (p < 0.05), with the 980 nm group having higher BMP-2 levels than the 810 nm group (p < 0.05). Bone sialoprotein expression was higher in laser-treated groups on days 14 and 28 (p < 0.05), and osteocalcin expression was highest in the 980 nm group on both days (p < 0.05). Micro-CT analysis showed no significant differences among groups in bone mineral density, bone surface (BS)/bone volume (BV), or bone volume (BV)/TV (total volume) indices. Conclusion: PBM with 980 nm and 810 nm lasers promotes early-stage hard tissue healing in extraction sockets, with the 980 nm laser more effectively enhancing osteogenic gene expression, suggesting its potential as an adjunctive therapy in dental and oral surgery.

NLRP3 deficiency improves bone healing of tooth extraction sockets through SMAD2/3-RUNX2 mediated osteoblast differentiation.

Impaired bone healing following tooth extraction poses a significant challenge for implantation. As a crucial component of the natural immune system, the NLRP3 inflammasome is one of the most extensively studied Pattern-Recognition Receptors (PRRs), and is involved in multiple diseases. Yet, the role of NLRP3 in bone healing remains to be clarified. Here, to investigate the effect of NLRP3 on bone healing, we established a maxillary first molar extraction model in wild-type (WT) and NLRP3KO mice using minimally invasive techniques. We observed that NLRP3 was activated during the bone repair phase, and its depletion enhanced socket bone formation and osteoblast differentiation. Moreover, NLRP3 inflammasome activation was found to inhibit osteogenic differentiation in alveolar bone-derived mesenchymal stem cells (aBMSCs), an effect mitigated by NLRP3 deficiency. Mechanistically, we established that SMAD2/3-RUNX2 signaling pathway is a downstream target of NLRP3 inflammasome activation, and SMAD2/3 knockdown partially reversed the significant decrease in expression of RUNX2, OSX, and ALP induced by NLRP3. Thus, our findings demonstrate that NLRP3 negatively modulates alveolar socket bone healing and contribute to the understanding of the NLRP3-induced signaling pathways involved in osteogenesis regulation.

Healing sequelae following tooth extraction and dental implant placement in an aged, ovariectomy model.

At present, a lack of consensus exists regarding the clinical impact of osteoporosis on alveolar bone metabolism during implant osseointegration. While limited preclinical and clinical evidence demonstrates a negative influence of osteoporosis on dental extraction socket healing, no preclinical studies offer data on the results of implant placement in 6-mo-old, ovariectomized (OVX) Sprague-Dawley rats. This study aimed to investigate the outcomes of dental tooth extraction socket healing and implant placement in a rodent model of osteoporosis following daily vehicle (VEH) or abaloparatide (ABL) administration. Micro-CT and histologic analysis demonstrated signs of delayed wound healing, consistent with alveolar osteitis in extraction sockets following 42d of healing in both the VEH and ABL groups. In a semiquantitative histological analysis, the OVX-ABL group demonstrated a tendency for improved socket regeneration with a 3-fold greater rate for moderate socket healing when compared to the OVX-VEH group (43% vs 14%), however, this finding was not statistically significant (p=.11). No significant differences were observed between vehicle and test groups in terms of implant outcomes (BMD and bone volume/total volume) at 14- and 21-d post-implant placement. Abaloparatide (ABL) significantly increased BMD of the femoral shaft and intact maxillary alveolar bone sites in OVX animals, demonstrating the therapeutic potential for oral hard tissue regeneration. The present model involving estrogen-deficiency-induced bone loss demonstrated an impaired healing response to dental extraction and implant installation.

Effects of Simvastatin-Loaded Nanomicelles on the Early Preservation of Tooth Extraction Sites.

The present study intended to evaluate the effect of simvastatin-loaded nanomicelles (SVNs) on promoting new bone formation and reducing alveolar ridge resorption at the tooth extraction sites at the early healing of the extraction sockets. SVNs were synthesized using a dialysis method. The rabbit tooth extraction model was established, SVNs and simvastatin (SV) were loaded on gelatin sponge and inserted into the extraction socket. CBCT scans were performed at 0, 2, and 4weeks postoperatively to evaluate bone formation and alveolar ridge absorption in the extraction sockets. And all the animals were sacrificed and the mandibles were harvested. And HE staining and Masson staining were used for histological evaluation of the bone formation in the extraction sockets. Radiographic evaluation showed that compared with the blank control group, at 2 and 4weeks after extraction, SVNs increased the new bone density in the extraction sockets by 75.7% and 96.5%, and reduced the absorption rate of alveolar ridge length at the extraction sites by 60.8% and 49.1%, respectively. Histological evaluation showed that SVNs significantly improved the maturation of new bone tissue in the extraction sockets. SVNs can significantly accelerate healing and effectively reduce the absorption of alveolar ridge at the extraction sites in the early stage of tooth extraction socket healing.

Spontaneous bacterial peritonitis and soft tissue healing after tooth extraction in liver cirrhosis patients

The objective of this study was to identify the association between tooth extraction and occurrence of spontaneous bacterial peritonitis (SBP) and to assess delayed soft tissue healing of extraction sockets in patients with cirrhosis. One hundred nineteen participants awaiting liver transplantation who required tooth extraction were included. Seven days before the surgery, the patients underwent panoramic radiography and laboratory examinations. Soft tissue healing was evaluated 7 days after the tooth extraction and medical records were checked after 21 days for development of SBP. The relationship between predictive factors and outcomes was assessed by using multiple binomial logistic regression. One hundred ninety-five teeth were extracted, resulting in 146 alveolar wounds, in which the majority (47%) consisted of alveolar sockets of multirooted teeth. One participant was diagnosed with SBP (Escherichia coli [E. coli]) and another diagnosed with bacterascites (Streptococcus viridans [S. viridans] group), occurring 11 and 6 days after tooth extraction. Poor soft tissue healing was observed in 20 (13.7%) patients, which was correlated to 2 risk factors, that is, jaundice (P = .007, adjusted odds ratio [OR] = 4.91, 95% confidence interval [CI] = 1.56-15.47) and moderate neutropenia (P = .048, adjusted OR = 13.99, 95% CI = 1.02-192.07). No association was found between tooth extraction and SBP in patients with cirrhosis. The delayed soft tissue healing was related to jaundice (hyperbilirubinemia) and moderate neutropenia.

Comprehensive analysis of bone tissue in extraction sockets of third molars after leukocyte and platelet rich fibrin and photobiomodulation applications

ObjectivesThe aim of this study was to compare leukocyte and platelet-rich fibrin (L-PRF) and photobiomodulation (PBM) applications, which have been repeatedly reported to be superior to control groups, in terms of pain, soft tissue and bone healing in tooth extraction sockets.Materials and methodsThis double-blind, randomized clinical study was completed with 34 patients, who had an indication for extraction of their bilaterally impacted teeth. The right and left teeth of the patients were randomly divided into L-PRF and PBM groups. L-PRF group was treated with the blood product centrifuged for 12 min at 2700 rpm, and the PBM group was treated with a diode laser at different points for 60 s with a wavelength of 940 nm in repeated sessions. Postoperative pain was evaluated using Visual Analogue Scale (VAS), soft tissue healing with Landry Index (LI), tissue healing in the distal region of mandibular second molar by probing depth measurement, and bone healing via panoramic x-ray using the Image J program.ResultsNo statistically significant difference was found for any variable compared between the groups.ConclusionL-PRF and PBM applications provide similar support in the healing of extraction sockets. Nevertheless, the advantages and disadvantages of both methods determine their usage areas.Clinical relevanceWhile L-PRF is advantageous in the early healing of extraction sockets, PBM may be preferred in terms of bone trabeculation in the long term.

The Role of Sodium Fluoride Mouthwash in Regulating FGF-2 and TGF-β Expression in Human Gingival Fibroblasts.

Sodium fluoride (NaF) is a fluoride application recommended by the World Health Organization for its efficacy and safety in preventing dental caries. Gingival fibroblasts that constitute the majority of connective tissue cells play a major role in wound healing via the expression of growth factors, including fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta (TGF-β). This study examined the effect of NaF mouthwash on FGF-2 and TGF-β expression in human gingival fibroblasts (HGnFs). Fibroblasts were exposed to a medium with 225 ppmF NaF for 1 min, then switched to either 15 ppmF NaF for continuous stimulation or no NaF for transient stimulation. Continuous NaF stimulation significantly increased the gene and protein expression of FGF-2 and TGF-β in HGnFs compared to controls, suggesting NaF's potential role in modulating periodontal tissue wound healing. Signaling pathway investigations showed the involvement of heterotrimeric GTP-binding proteins, calcium/calmodulin-dependent kinase II (CaMKII), and extracellular signal-regulated kinase (ERK) phosphorylation. Inhibiting CaMKII reduced NaF-induced FGF-2 and TGF-β expression, while ERK phosphorylation increased after NaF stimulation. These results highlight NaF mouthwash's potential in promoting wound healing in extraction sockets, particularly during the mixed dentition period. Understanding NaF's effects is clinically relevant due to the common use of fluoride products.

Evaluation of 4 and 8 Weeks of Healing in a Murine Implant Model.

Dental implants are increasing in prevalence as desirable options for replacing missing teeth. Unfortunately, implants come with complications, and animal models are crucial to studying the pathophysiology of complications. Current murine model experiments can be lengthy, with 8 weeks of extraction socket healing before implant placement. Therefore, we aimed to investigate the efficacy of decreasing extraction healing time from 8 to 4 weeks in a dental implant mouse model. Thirty-one 3-week-old C57BL/6J male mice underwent maxillary first and second molar extractions followed by 8 (control) or 4 (test) weeks of extraction socket healing before implant placement. Mice were euthanized after 4 weeks of implant osseointegration. Samples were analyzed via microcomputerized tomography and histology. When mice received implants 4 weeks after extractions, there was no statistical difference in initial bone crest remodeling or surrounding bone volume compared to those after 8 weeks of healing. Histologically, the hard and soft tissues surrounding both groups of implants displayed similar alveolar bone levels, inflammatory infiltrate, osteoclast count, and collagen organization. A 4-week extraction healing period can be utilized without concern for osseointegration in a murine implant model and is a viable experimental alternative to the previous eight weeks of healing. While small animal implant models are less directly applicable to humans, advancements in experimental methods will ultimately benefit patients receiving dental implants through improved prevention and treatment of complications. Subsequent research could investigate occlusal effects or whether healing time affects prognosis after induction of peri-implantitis.

Role of sclerostin deletion in bisphosphonate-induced osteonecrosis of the jaw

PurposeBone resorption inhibitors, such as bisphosphonates (BP) and denosumab, are frequently used for the management of osteoporosis. Although both drugs reduce the risk of osteoporotic fractures, they are associated with a serious side effect known as medication-related osteonecrosis of the jaw (MRONJ). Sclerostin antibodies (romosozumab) increase bone formation and decrease the risk of osteoporotic fractures: however, their anti-resorptive effect increases ONJ. Thus, this study aimed to elucidate the role of sclerostin deletion in the development of MRONJ. MethodsSclerostin knockout (SostΔ26/Δ26) mice were used to confirm the development of ONJ by performing tooth extractions. To confirm the role of sclerostin deficiency in a more ONJ-prone situation, we used the BP-induced ONJ model in combination with severe periodontitis to evaluate the development of ONJ and bone formation in wild-type (WT) and SostΔ26/Δ26 mice. Wound healing assay using gingival fibroblasts with or without sclerostin stimulation and tooth extraction socket healing were evaluated in the WT and SostΔ26/Δ26 mice. ResultsONJ was not detected in the extraction socket of SostΔ26/Δ26 mice. Moreover, the incidence of ONJ was significantly lower in the SostΔ26/Δ26 mice treated with BP compared to that of the WT mice. Osteogenic proteins, osteocalcin, and runt-related transcription factor 2, were expressed in the bone surface in SostΔ26/Δ26 mice. Recombinant sclerostin inhibited gingival fibroblast migration. The wound healing rate of the extraction socket was faster in SostΔ26/Δ26 mice than in WT mice. ConclusionSclerostin deficiency did not cause ONJ and reduced the risk of developing BP-induced ONJ. Enhanced bone formation and wound healing were observed in the tooth extraction socket. The use of romosozumab (anti-sclerostin antibody) has proven to be safe for surgical procedures of the jaw.

“Comparative Study on the Effect of Nano- hydroxyapatite and Theobromine on Healing of Extraction Socket in Albino Rats (Histological and Immuno-Histochemical Study)’’

“Comparative Study on the Effect of Nano- hydroxyapatite and Theobromine on Healing of Extraction Socket in Albino Rats (Histological and Immuno-Histochemical Study)’’

Microbial colonization in the partially exposed nonabsorbable membrane during alveolar ridge preservation.

This study evaluated the impact of the partial exposition of the nonabsorbable membrane (dPTFE) on microbial colonization during bone healing. Patients indicated for tooth extraction were randomized to dPTFE group (n = 22) - tooth extraction and alveolar ridge preservation (ARP) using an intentionally exposed dPTFE membrane and USH group (n = 22) - tooth extraction and unassisted socket healing. Biofilm samples were collected at the barrier in the dPTFE and on the natural healing site in the USH after 3 and 28 days. Samples from the inner surface of the dPTFE barrier were also collected (n = 13). The microbiome was evaluated using the Illumina MiSeq system. Beta diversity was different from 3 to 28 days in both groups, and at 28 days, different microbial communities were identified between therapies. The dPTFE was characterized by a higher prevalence and abundance of gram-negative and anaerobic species than USH. Furthermore, the inner surface of the dPTFE membrane was colonized by a different community than the one observed on the outer surface. Intentionally exposed dPTFE membrane modulates microbial colonization in the ARP site, creating a more homogeneous and anaerobic community on the inner and outer surfaces of the membrane. DPTFE promoted faster biofilm colonization and enrichment of gram-negative and anaerobes close to the regenerated site in the membrane's inner and outer surfaces. dPTFE membrane can be used exposed to the oral site, but approaches for biofilm control should still be considered. The study was retrospectively registered at Clinicaltrials.gov (NCT04329351).

Detection of senescent cells in the mucosal healing process on type 2 diabetic rats after tooth extraction for biomaterial development.

The delayed mucosal healing of tooth extraction sockets in diabetes has few known effective treatment strategies, and its underlying mechanism remains unknown. Senescent cells may play a pivotal role in this delay, given the well-established association between diabetes, senescent cells, and wound healing. Here, we demonstrated an increase in p21- or p16-positive senescent cells in the epithelial and connective tissues of extraction sockets in type 2 diabetic rats compared to those in control rats. Between 7 and 14 days after tooth extraction, a decrease in senescent cells and improvement in re-epithelialization failure were observed in the epithelium, while an increase in senescent cells and persistence of inflammation were observed in the connective tissue. These results suggest that cellular senescence may have been induced by diabetes and contributed to delayed mucosal healing by suppressing re-epithelization and persistent inflammation. These findings provide new targets for treatment using biomaterials, cells, and drugs.

An Injectable Black Phosphorus Hydrogel for Rapid Tooth Extraction Socket Healing.

The excess production of reactive oxygen species (ROS) will delay tooth extraction socket (TES) healing. In this study, we developed an injectable thermosensitive hydrogel (NBP@BP@CS) used to treat TES healing. The hydrogel formulation incorporated black phosphorus (BP) nanoflakes, recognized for their accelerated alveolar bone regeneration and ROS-scavenging properties, and dl-3-n-butylphthalide (NBP), a vasodilator aimed at enhancing angiogenesis. In vivo investigations strongly demonstrated that NBP@BP@CS improved TES healing due to antioxidation and promotion of alveolar bone regeneration by BP nanoflakes. The sustained release of NBP from the hydrogel promoted neovascularization and vascular remodeling. Our results demonstrated that the designed thermosensitive hydrogel provided great opportunity not only for ROS elimination but also for the promotion of osteogenesis and angiogenesis, reflecting the "three birds with one stone" concept, and has tremendous potential for rapid TES healing.

Comparison between the Effects of Stem Cells and Lepidium Sativum on the Healing of Extraction Socket in Albino Rats (Histological and Immunohistochemical Study)

Comparison between the Effects of Stem Cells and Lepidium Sativum on the Healing of Extraction Socket in Albino Rats (Histological and Immunohistochemical Study)

4-Octyl itaconate promotes alveolar ridge preservation following tooth extraction.

The search for medications that can effectively reduce alveolar bone loss following tooth extraction is of great interest. This study aimed to observe the roles of 4-octyl itaconate (4-OI) in RANKL-induced osteoclastogenesis of bone marrow macrophages (BMMs) in vitro. Mandibular second molars were extracted to evaluate whether 4-OI could alleviate alveolar bone loss. 4-OI inhibited RANKL-induced osteoclastogenesis and promoted Nrf2 expression in bone marrow macrophages in vitro. Positive Nrf2 expressions were observed in inflammatory cells and osteoclasts in vivo. Treatment with 4-octyl itaconate increased Nrf2 expression, resulting in reduced inflammatory infiltration and osteoclastic activity after tooth extraction. Furthermore, increased expression of OCN and enhanced-alveolar bone healing of extraction socket were observed in the 4-OI group compared to the control group. Our results suggested that 4-OI could serve as a promising pharmacologic candidate for alveolar ridge preservation by alleviating alveolar bone loss following tooth extraction in rats.

Effect of low-level laser therapy in wound healing of primary molar teeth extraction

IntroductionTooth extraction in children requires attention to wound healing and pain management, which are influenced by patient-related factors and behavioral guidance. Aim of the study: The study aimed to evaluate the effect of LLLT on healing sockets in pediatric patients with bilateral primary molar teeth extraction and determine its impact on pain management.Methods6–10 years of age, systemically healthy, and with atraumatic extraction indications of bilateral primary molar teeth were included in the study (n = 40). In the first session, randomly selected teeth were extracted under local anesthesia. In the control group, only clot formation in the socket was observed and photographed. The other group extractions were performed 2 weeks later. The low-level laser therapy (LLLT) group was treated with a 980 nm wavelength, in a continuous emission mode, 0.5 W power, 300 J of energy, 400 µm tip, 60 s diode laser and photographed. Nonepithelialized surface measurements were performed using ImageJ. Pain assessment was performed using the Wong-Baker Pain Scale. Statistical analyses were performed using SPSS software.ResultsThere was a statistically significant difference between the groups in the Wong-Baker values in 3rd day (p < 0.05). In soft tissue healing on the 3rd and 7th day, the nonepithelialized surface of the laser socket was smaller than that of the control group, and the measurement results were found to be statistically significant (p < 0.05).ConclusionAlthough LLLT was not found to be very effective in reducing postoperative discomfort after extraction of primary molars, it provided better wound healing in extraction sockets.

Leptin receptor (+) stromal cells respond to periodontitis and attenuate alveolar bone repair via CCRL2-mediated Wnt inhibition.

The impaired bone healing in tooth extraction sockets due to periodontitis presents a major obstacle to restoring oral health. The mechanisms regulating the osteogenic capacity of jawbone-derived stromal cells in the periodontitis microenvironment remain elusive. Leptin receptor (LepR) expressing stromal cells, which largely overlap with Cxcl12-abundant reticular (CAR) cells in bone tissue, rapidly proliferate and differentiate into bone-forming cells during extraction socket healing to support alveolar bone repair. In this study, we identify that CCRL2 is significantly expressed and inhibits osteogenesis in LepR+/CAR cells of alveolar bones with periodontitis. The Ccrl2-KO mice exhibit significant improvements in bone healing in extraction sockets with periodontitis. Specifically, the binding of CCRL2 to SFRP1 on the surface of LepR+/CAR cells can amplify the suppressive effect of SFRP1 on Wnt signaling under inflammation, thus hindering the osteogenic differentiation of LepR+/CAR cells and resulting in poor bone healing in extraction sockets with periodontitis. Together, we clarify that the CCRL2 receptor of LepR+/CAR cells can respond to periodontitis and crosstalk with Wnt signaling to deteriorate extraction socket healing.

Regeneration of alveolar bone defects in the experimental pig model: A systematic review and meta-analysis.

Pigs are emerging as a preferred experimental invivo model for bone regeneration. The study objective was to answer the focused PEO question: in the pig model (P), what is the capacity of experimental alveolar bone defects (E) for spontaneous regeneration in terms of new bone formation (O)? Following PRISMA guidelines, electronic databases were searched for studies reporting experimental bone defects or extraction socket healing in the maxillae or mandibles of pigs. The main inclusion criteria were the presence of a control group of untreated defects/sockets and the assessment of regeneration via 3D tomography [radiographic defect fill (RDF)] or 2D histomorphometry [new bone formation (NBF)]. Random effects meta-analyses were performed for the outcomes RDF and NBF. Overall, 45 studies were included reporting on alveolar bone defects or extraction sockets, most frequently in the mandibles of minipigs. Based on morphology, defects were broadly classified as 'box-defects' (BD) or 'cylinder-defects' (CD) with a wide range of healing times (10 days to 52 weeks). Meta-analyses revealed pooled estimates (with 95% confidence intervals) of 50% RDF (36.87%-63.15%) and 43.74% NBF (30.47%-57%) in BD, and 44% RDF (16.48%-71.61%) and 39.67% NBF (31.53%-47.81%) in CD, which were similar to estimates of socket-healing [48.74% RDF (40.35%-57.13%) and 38.73% NBF (28.57%-48.89%)]. Heterogeneity in the meta-analysis was high (I2 > 90%). A substantial body of literature revealed a high capacity for spontaneous regeneration in experimental alveolar bone defects of (mini)pigs, which should be considered in future studies of bone regeneration in this animal model.

Bone formation in large/moderate gap after immediate implantation in response to different treatments: a pre-clinical study in the canine posterior mandible.

This study aims to investigate different treatments on new bone formation around immediate implants in the canine posterior mandible with varying sized mesial-distal gap. The 4th premolar and the 1st molar of six Labrador dogs were extracted from the mandible, and 4 dental implants were placed 1mm below the level of the buccal bone crest. Moderate/large mesial-distal gaps between the implants and the sockets were treated with one of four methods and divided into the following groups: (1) the blank group, (2) the collagen membrane (CM) group, (3) the deproteinized bovine bone mineral (DBBM) group, and (4) the DBBM + CM group. Sequential fluorescent labeling was performed at 4, 8, and 10 weeks after the operation. After 12 weeks, the dogs were euthanized, and specimens were collected for micro-CT scanning and histological analysis. The survival rate of immediate implant was 100%. Micro-CT showed significant differences in bone mineral density (BMD) and bone volume fraction (BVF) among groups (P = 0.040, P = 0.009); other indicators were not significantly different among groups. Histological analysis showed the proportion of new bone formation and bone-to-implant contact were not significantly different among groups. No significant difference in bone reduction height around dental implant among four groups and varied mesial-distal gap size. Owing to the restricted sample size, this pilot study lacks conclusive findings. Within the limitation, this study demonstrated that although DBBM significantly increase BMD and BVF, the use of DBBM/CM didn't significantly improve bone formation and healing in extraction sockets around the implants in both moderate and large mesial-distal gap. The use of deproteinized bovine bone in conjunction with collagen is a common practice in immediate implantation procedures in the posterior mandible. However, there is a lack of conclusive evidence regarding the timing and circumstances under which they should be employed.