Ridge preservation with the use of Bio-Oss®collagen: A 6-month study in the dog

Intraoral ultrasonography image registration for evaluation of partial edentulous ridge: A methodology and validation study

OBJECTIVES

Ultrasound (US) reveals details for diagnosing soft- and hard-tissue dimensions around teeth, implants, and the edentulous ridge, not seen in 2D radiographs. Co-registering free-hand US scans with other 3D modalities presents reliability challenges. This study first aims to develop and validate a registration method to longitudinally reproduce US images of the jawbone on a simulator. In addition, it also evaluates the degree of the anatomical match in humans between US images acquired by the proposed registration method and the commonly used freehand acquisitions in comparison to cone beam computed tomography (CBCT) and intra-oral optical scan (IOS), used as references.

METHODS

A previously introduced ultrasound phantom was employed as a CBCT-US hybrid, suitable for training and technique development of US guides in edentulous ridges. After establishing feasibility in the phantom, the methodology was validated in a cohort of 24 human subjects (26 cases). Soft tissues were delineated on US and IOS, and hard tissues on US and CBCT. US accuracy and repeatability from both guided and freehand scans (non-guided) was assessed as the average distance between US and the references.

RESULTS

Guided US images resembled the references more closely than freehand (non-guided) scans. Notably, delineation of soft and hard tissues was significantly more accurate when employing guides. In the phantom, guided scans exhibited an absolute mean deviation of 81.8 µm for gingiva and 90.4 µm for bone, whereas non-guided scans showed deviations of 150.4 µm and 177.2 µm, respectively. Similarly, in vivo, guided US outperformed non-guided US, with gingiva deviations of 125 µm and 196 µm, and bone deviations of 354 µm and 554 µm, respectively.

CONCLUSIONS

By using a registration method, guided US scans improved repeatability and accuracy of mapping hard and soft tissue of the edentulous ridge when compared to non-guided scans.

CLINICAL RELEVANCE

This guided US imaging method could lay the foundation for longitudinal evaluation of tissue behavior and dimensional changes with improved accuracy.

Alveolar ridge preservation versus early implant placement in single non-molar sites: A systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analyses was to evaluate the outcomes of alveolar ridge preservation (ARP) following extraction of non-molar teeth in comparison to early implant placement (EIP) in terms of clinical and radiographic changes, need for additional augmentation at the time of implant placement, patient-reported outcomes, and implant failure rate.

METHODS

Electronic databases were searched to identify randomized and non-randomized studies that compared ARP to EIP. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool. Data were analyzed using a statistical software program.

RESULTS

A total of 106 studies were identified, of which five studies with 198 non-molar extraction sockets in 198 participants were included. Overall meta-analysis showed significant differences in changes in midfacial mucosal margin (mean difference (MD) -0.09; 95% confidence interval (CI) -0.17 to -0.01; p = .03) and ridge width (MD -1.70; 95% CI -3.19 to -0.20; p = .03) in favor of ARP. The use of ARP was also associated with less need for additional augmentation at implant placement, but the difference was not statistically significant.

CONCLUSIONS

Within the limitation of this review, ARP following extraction of non-molar teeth has short-term positive effects on soft tissue contour, mucosal margin and thickness, and alveolar ridge width and height. It can also simplify future implant treatment by minimizing the need for additional augmentation.

Healing of Extraction Sites after Alveolar Ridge Preservation Using Advanced Platelet-Rich Fibrin: A Retrospective Study

BACKGROUND

Over time, numerous surgical procedures and biomaterials have been proposed for the reconstruction of post-extraction bone defects, each with their advantages and disadvantages. The main objective of this study was to evaluate dimensional changes in the alveolar bone 3 months after tooth extraction, before implant planning, comparing alveolar ridge preservation (ARP) with spontaneous healing.

METHODS

A total of 84 patients with non-restorable molars were included in the study. Forty-two patients received ARP with advanced platelet-rich fibrin (A-PRF) and spontaneous healing was evaluated in these patients. Cone beam computed tomography (CBCT) analysis performed before and after surgical intervention was used to determine the changes in vertical and horizontal bone dimensions produced after tooth extraction.

RESULTS

CBCT measurements showed reduction in both vertical and horizontal alveolar bone size in both groups. For the study group, the alveolar parameters (height, width) were higher compared to the control group. The percentage variations between dimensional differences from the two groups were 38.58% for height, and for width were 36.88% at 0 mm, 35.56% at 3 mm, 36.61% at 5 mm, and 38.73% at 7 mm. The differences were statistically significant (p ˂ 0.0005).

CONCLUSIONS

The results obtained after ARP with A-PRF showed a reduced loss of bone volume compared to spontaneous healing.

Ultrasound-based jawbone surface quality evaluation after alveolar ridge preservation

BACKGROUND

Bone readiness for implant placement is typically evaluated by bone quality/density on 2-dimensional radiographs and cone beam computed tomography at an arbitrary time between 3 and 6 months after tooth extraction and alveolar ridge preservation (ARP). The aim of this study is to investigate if high-frequency ultrasound (US) can classify bone readiness in humans, using micro-CT as a reference standard to obtain bone mineral density (BMD) and bone volume fraction (BVTV) of healed sockets receiving ARP in humans.

METHODS

A total of 27 bone cores were harvested during the implant surgery from 24 patients who received prior extraction with ARP. US images were taken immediately before the implant surgery at a site co-registered with the tissue biopsy collection location, made possible with a specially designed guide, and then classified into 3 tiers using B-mode image criteria (1) favorable, (2) questionable, and (3) unfavorable. Bone mineral density (hydroxyapatite) and BVTV were obtained from micro-CT as the gold standard.

RESULTS

Hydroxyapatite and BVTV were evaluated within the projected US slice plane and thresholded to favorable (>2200 mg/cm3; >0.45 mm3/mm3), questionable (1500-2200 mg/cm3; 0.4-0.45 mm3/mm3), and unfavorable (<1500 mg/cm3; <0.4 mm3/mm3). The present US B-mode classification inversely scales with BMD. Regression analysis showed a significant relation between US classification and BMD as well as BVTV. T-test analysis demonstrated a significant correlation between US reader scores and the gold standard. When comparing Tier 1 with the combination of Tier 2 and 3, US achieved a significant group differentiation relative to mean BMD (p = 0.004, true positive 66.7%, false positive 0%, true negative 100%, false negative 33.3%, specificity 100%, sensitivity 66.7%, receiver operating characteristics area under the curve 0.86). Similar results were found between US-derived tiers and BVTV.

CONCLUSION

Preliminary data suggest US could classify jawbone surface quality that correlates with BMD/BVTV and serve as the basis for future development of US-based socket healing evaluation after ARP.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model

This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

The adjunctive effect of polydeoxyribonucleotide on bone formation in alveolar ridge preservation: A pre-clinical in vivo study

AIM

This study investigated the adjunctive effect of polydeoxyribonucleotide (PDRN) on bone formation in alveolar ridge preservation (ARP) sockets.

MATERIALS AND METHODS

Both mandibular second, third and fourth premolars of eight beagle dogs were randomly divided into ARP and ARP/PDRN groups. Following tooth extraction, ARP procedures were conducted using collagenized alloplastic graft material and bilayer collagen membrane soaked with normal saline (ARP group) or PDRN (ARP/PDRN group) for 10 min before application. Both groups were also randomly allocated to 2-, 4- or 12-week healing subgroups. The primary endpoint of this study was to compare histomorphometric differences between ARP and ARP/PDRN. The secondary endpoints of this study were to compare micro-CT analysis and three-dimensional volumetric measurement between the two groups.

RESULTS

In the histomorphometric analysis, the ARP/PDRN group exhibited greater new bone formation at coronal, middle and total position compared with the ARP group at 2-week healing. The number of newly formed blood vessels was higher in the ARP/PDRN group than in the ARP group at 2- and 4-week healing. In micro-CT analysis, the mean new bone volume/total bone volume between ARP and ARP/PDRN was statistically significant at 2-week healing. Ridge volume alterations were significantly decreased in the ARP/PDRN group during entire healing time compared with the ARP group, especially on the buccal side.

CONCLUSIONS

The application of PDRN in ARP might provide additional benefits for early bone regeneration and maintenance of buccal ridge volume.

Effect of radiation cross-linked collagen scaffold in alveolar ridge preservation of extraction socket

This study aimed to evaluate the properties of radiation cross-linked collagen scaffold (RCS) and its efficacy for alveolar ridge preservation (ARP). RCS was prepared from collagen dispersion by electron beam irradiation and freeze-drying. The microstructure, swelling ratio, area alteration and mechanical properties of RCS were characterized. Fifty-four New Zealand rabbits performing incisor extraction on maxilla and mandible were randomly assigned into positive, sham operation or treatment groups. Micro-computed tomography (micro-CT) scans, performed after 1, 4, and 12 weeks of surgery, were to assess changes in ridge height at buccal and palatal side, in ridge width and in micromorphological parameters. Histological analysis accessed socket microarchitecture. The results showed that RCS had stable mechanical properties and morphologic features that provided a reliable physical support for ARP. Dimensional changes in treatment group revealed significantly greater vertical height at buccal (5.32 [3.37, 7.26] mm, p < .0001) and palatal (4.37 [2.66, 6.09] mm, p < .0001) side, and horizontal width at the maxilla (0.16 [0.04, 0.28] mm, p < .01) and mandible (0.33 [0.11, 0.54] mm, p < .01) than those in sham operation group after 12 weeks. The treatment group had advantage than positive group in vertical height preservation, quantitatively. The order and density of bone trabeculae were improved in treatment group. These findings indicated that RCS had the potential to serve as an effective scaffold for ARP.

Application of modified porcine xenograft by collagen coating in the veterinary field: pre-clinical and clinical evaluations

Introduction

This study aimed to identify a collagen-coating method that does not affect the physicochemical properties of bone graft material. Based on this, we developed a collagen-coated porcine xenograft and applied it to dogs to validate its effectiveness.

Methods

Xenografts and collagen were derived from porcine, and the collagen coating was performed through N-ethyl-N'-(3- (dimethylamino)propyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) activation. The physicochemical characteristics of the developed bone graft material were verified through field emission scanning electron microscope (FE-SEM), brunauer emmett teller (BET), attenuated total reflectance-fourier transform infrared (ATR-FTIR), and water absorption test. Subsequently, the biocompatibility and bone healing effects were assessed using a rat calvarial defect model.

Results

The physicochemical test results confirmed that collagen coating increased bone graft materials' surface roughness and fluid absorption but did not affect their porous structure. In vivo evaluations revealed that collagen coating had no adverse impact on the bone healing effect of bone graft materials. After confirming the biocompatibility and effectiveness, we applied the bone graft materials in two orthopedic cases and one dental case. Notably, successful fracture healing was observed in both orthopedic cases. In the dental case, successful bone regeneration was achieved without any loss of alveolar bone.

Discussion

This study demonstrated that porcine bone graft material promotes bone healing in dogs with its hemostatic and cohesive effects resulting from the collagen coating. Bone graft materials with enhanced biocompatibility through collagen coating are expected to be widely used in veterinary clinical practice.

Recombinant bone matrix maintains the graft space, induces vascularized bone regeneration and preserves canine tooth extraction socket structure

AIM

Recombinant bone matrix (RBM) is a newly conceived and engineered porous bone graft granule of average size 600 μm composed of purified recombinant collagen peptide. We sought to examine the behaviour with time of RBM that was grafted in the canine tooth extraction socket.

MATERIALS AND METHODS

The canine tooth extraction socket of the hemisectioned mandibular third premolar distal root was grafted with RBM granules, whereas the opposite side extraction socket served as non-grafted control. The mandibular samples were harvested at 1, 3 and 6 months of healing and subjected to micro-CT imaging and decalcified paraffin-embedded histology. Separately, the effect of RBM was compared with that of deproteinized cancellous bovine bone (DCBB) and bovine atelocollagen plug (BACP) in the canine tooth extraction model at 3 months of healing.

RESULTS

RBM maintained the grafted space in the socket and the gingival connective tissue until new bone was formed within its porous space. The regenerated bone was highly vascularized and continued to mature, while RBM was completely bioresorbed by 6 months. The buccal and lingual alveolar ridge heights of the RBM-grafted extraction socket was better preserved than those of non-grafted control sockets. The degree of socket preservation by RBM was equivalent to that by DCBB, although their healing mechanisms were different.

CONCLUSIONS

This study demonstrated that RBM induced controlled active bone regeneration and preserved the extraction socket structure in a canine model. Bioresorbable RBM engineered without animal or human source materials presents a novel bone graft category with robust bone regenerative property.

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.

Alveolar ridge preservation in sockets with severe periodontal destruction using autogenous partially demineralized dentin matrix: A randomized controlled clinical trial

BACKGROUND

The preservation and reconstruction of alveolar ridge volume in extraction sockets of molars affected by severe periodontitis is a critical challenge that requires clinical attention.

PURPOSE

This randomized controlled clinical trial was designed to evaluate the efficiency of autogenous partially demineralized dentin matrix (APDDM) for alveolar ridge preservation (ARP) in severely periodontally compromised sockets compared to spontaneous healing (SH) on radiographic and histomorphometric outcomes.

MATERIALS AND METHODS

Thirty-two patients with 32 periodontally compromised molars were randomized into either the test group, which received ARP using APDDM covered with a collagen sponge, or the control group, which underwent SH. Linear and volumetric changes were assessed using superimposed cone-beam computed tomography (CBCT) acquired pre-extraction and after a 4-month healing time. Histomorphometric evaluation was performed on trephine cores harvested during implant placement.

RESULTS

All sites healed uneventfully. The ridge width at 1 mm apical to the bone crest increased by 5.03, 4.50, and 5.20 mm in the mesial, middle, distal area in the APDDM group, while decreasing by -1.98, -2.19, and -1.98 mm in the SH group, respectively (p < 0.05). The height increase of the central bone was significantly higher in the APDDM group than in the SH group (p < 0.05). The height decrease of the buccal (mesial, middle, distal) bone plate was lower in the APDDM group than in the SH group (p < 0.05). After a 4-month healing time, bone volume increased by 37.07% in the APDDM group and by only 2.33% in the SH group (p < 0.05). Histomorphometric analysis revealed that APDDM particles were surrounded by newly formed bone, with partially absorbed residual APDDM materials observed. New bone, APDDM remnants, and connective tissue occupied 39.67 ± 8.28%, 23.66 ± 9.22%, and 36.67 ± 17.05% of the areas in the APDDM group, respectively.

CONCLUSIONS

ARP using APDDM was effective, resulting in a significant increase in both linear and volumetric changes in severely periodontally compromised extraction sockets compared to SH. These findings suggest that APDDM may serve as a promising new clinical option for the reconstruction of alveolar ridge dimensions.

Anatomical characteristics of the alveolar process and basal bone that have an effect on socket healing

Following tooth extraction, a sequence of events takes place in order to close the wound and restore tissue homeostasis, a process called socket healing. The outcome of socket healing includes a marked reduction of the ridge dimensions. The amount of tissue loss that occurs during healing is influenced by several local and systemic factors. Thus, the aim of the present review was to describe the effect of anatomical characteristics of the alveolar process and basal bone on the socket healing outcome. The studies included showed that the quantity (number) and quality (composition) of socket walls exhibited a significant influence on the ridge diminution. A damaged socket (3 walls or less), as well as a thin buccal bone wall, which quickly resorbs negatively affected the healing outcome. Periodontally compromised sockets appeared to promote more extensive dimensional changes. Angulation between tooth and basal bone in addition to basal bone dimensions may also have altered the wound environment and influenced socket healing. The findings from the present review suggest that some anatomical characteristics of the alveolar process and basal bone have an effect on socket healing.

Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Clinical and Tomographic Study

Horizontal bone augmentation is a common surgical procedure used in implant therapy to achieve adequate bone volume to permit dental implant placement. However, most current techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate a new device that will permit bidirectional bone augmentation. Ten patients of both sexes (7 women and 3 men), with ages ranging from 29 to 62 years, who needed a bidirectional horizontal bone augmentation in maxilla were separated in accordance with the horizontal alveolar change (HAC) classification published by Pelegrine et al (2018). The patients classified as HAC 3 (ie, containing remaining cancellous bone at the recipient bed) received the Barbell device with xenogeneic biomaterial and a collagen membrane, whereas HAC 4 patients (ie, with no remaining cancellous bone at the recipient bed) received the Barbell device with a mixture of autogenous bone chips and xenogeneic biomaterial covered by a collagen membrane. For each patient, two computerized tomography scans were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness (T0) in the studied sites were 3.25 ± 0.35 in HAC 3 and 1.98 ± 0.5 in HAC 4 patients. The mean bone thickness achieved after 6 months was 7.70 ± 0.89 mm and 8.62 ± 0.89 in HAC 3 and 4, respectively. All grafted sites were able to receive dental implants in adequate prosthetic positions. Based on these results, the use of this novel device permits bidirectional horizontal bone augmentation.

Cone-Beam Computed Tomography and Histological Findings for Socket Preservation Techniques Using Different Grafting Materials: A Systematic Review

OBJECTIVE

Socket preservation techniques have been used to maintain the ridge dimension following tooth extraction. The materials used influence the quality and quantity of newly formed bone. Therefore, the aim of this article was to systematically review the literature reporting both histological and radiographic outcomes of socket preservation techniques after tooth extraction in human subjects.

MATERIAL AND METHOD

A systematic electronic search was performed in the electronic databases. English language clinical studies that were published between 2017 and 2022 and included both histological and radiographic findings for the test and control groups. Our primary search produced 848 articles, and of these, 215 were duplicate studies. A total of 72 articles were then eligible for full-text reading.

RESULTS

The review included eight studies that met its inclusion criteria. Three outcomes were compared in the included studies. The percentage of newly formed bone ranged from 21.34 ± 9.14% to more than 50% of new bone formation. The materials that showed more than 50% of newly formed bone formation were demineralized dentin graft, platelet-rich fibrin, freeze-dried bone allograft, corticocancellous porcine, and autogenous bone. Four Studies did not report the percentage of the residual graft materials, while those who reported showed a variable range of a minimum 1.5% to more than 25%. One study did not report the changes in horizontal width at the follow-up period, while other studies ranged from 0.6 mm to 10 mm.

CONCLUSION

Socket preservation represents an efficient technique to preserve the ridge contour with satisfactory newly formed bone in the augmented site and maintaining the vertical and horizontal dimensions of the ridge.

Soft-tissue dimensional change following guided bone regeneration on peri-implant defects using soft-type block or particulate bone substitutes: 1-year outcomes of a randomized controlled clinical trial

AIM

To compare the peri-implant soft-tissue dimensional changes following guided bone regeneration between particulate (particle group) and collagenated soft-block-type (block group) biphasic calcium phosphate (BCP).

MATERIALS AND METHODS

This study investigated 35 subjects: 18 in the particle group and 17 in the block group. Cone-beam computed tomography obtained at 6 months post surgery and optical impressions taken periodically (before surgery, 6 months post surgery, and 1 year post surgery) were superimposed. The ridge contour changes over time and the peri-implant mucosal thicknesses were measured diagonally and horizontally, and analysed statistically.

RESULTS

The increases in diagonal (1.12 ± 0.78 mm) and horizontal (2.79 ± 1.90 mm) ridge contour of the block group were significantly higher than those in the particle group during the first 6 months (p < .05); however, the contour hardly changed thereafter (diagonal: 0.07 ± 0.75 mm; horizontal: -0.34 ± 1.26 mm), resulting in the 1-year contour changes similar between the two groups. Regardless of the type of BCP, the ridge contour increased significantly over 1 year when the dehiscence defect had a contained configuration (p < .05).

CONCLUSIONS

The increase in soft-tissue dimensions for 1 year was similar between the two groups. The mucosal contour increase was larger when the surgery was conducted in a more contained defect, and this was not influenced by the type of BCP.

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.

Immediate implants with buccal defects filled with bone from the tuberosity or a xenograft: 1-year randomized trial

The aim of this study was to compare the use of autologous bone from tuberosity (TUBER) and deproteinized bovine bone mineral (DBBM) in immediate implants with buccal bone defects. A total of 31 patients with one single tooth in the upper anterior region indicated for extraction presenting tomographic buccal bone defect were analyzed. Immediate implantation was conducted for all patients. In one group, DBBM and a collagen membrane were inserted into the buccal defect; in the other group, a small block of bone from tuberosity was used. The primary outcome was facial-palatal ridge thickness (FPT) measured in casts 1 year after function. The implant success rate was 100% in both groups. FPT changes were <0.5 mm and did not differ significantly between groups. FPT reductions in the DBBM and TUBER groups were 1% and 0.6%, respectively, at the gingival margin and 5% and 2%, respectively, at 6 mm apical of the gingival margin (p > 0.05). No significant differences were observed between groups for patient's esthetic, satisfaction, pain and quality of life. Pink esthetic scores for the DBBM and TUBER were 11.5±1.7 and 10.8±1.9, respectively (p=0.37). It can be concluded that DBBM and TUBER did not differ in terms of ridge alterations, peri-implant clinical parameters and patient-reported outcomes.

A comparison between anorganic bone and collagen-preserving bone xenografts for alveolar ridge preservation: systematic review and future perspectives

After tooth extraction, dimensional changes affect the alveolar socket, leading to loss in alveolar bone height and width. Histological modifications also occur, with initial formation of a blood clot that is replaced with granulation tissue and subsequently with a provisional connective tissue matrix. Spontaneous healing ends with socket filling with woven bone, which is gradually replaced with lamellar bone and bone marrow. Adequate alveolar ridge dimensions and bone quality are required to assure optimal stability and osseointegration following dental implant placement. When a tooth is extracted, alveolar ridge preservation (ARP) procedures are an effective method to prevent collapse of the post-extraction socket. Heterologous bone is widely chosen by clinicians for ARP, and anorganic bone xenografts (ABXs) made bioinert by heat treatment represents the most used biomaterial in clinical applications. Collagen-preserving bone xenografts (CBXs) made of porcine or equine bone are fabricated by less invasive chemical or enzymatic treatments to remove xenogenic antigens, and these are also effective in preserving post-extraction sites. Clinical differences between anorganic bone substitutes and collagen-preserving materials are not well documented in the literature but understanding these differences could clarify how processing protocols influence biomaterial behavior in situ. This systematic review of the literature compares the dimensional changes and histological features of ABXs versus CBXs in ridge preservation procedures to promote awareness of different bone xenograft efficacies in stimulating the healing of post-extraction sockets.

Alveolar ridge preservation in extraction sockets of periodontally compromised teeth: a systematic review and meta-analysis

OBJECTIVES

Alveolar ridge preservation (ARP) procedures can limit bone changes following tooth extraction. However, the role of ARP in periodontally compromised socket lacks strong scientific evidence. The aim of this systematic review and meta-analysis was to evaluate the outcomes of ARP following extraction of periodontally compromised teeth in comparison to extraction alone in terms of hard tissue changes, need for additional augmentation at the time of implant placement and patient-reported outcomes.

MATERIAL AND METHODS

Electronic databases were searched to identify randomized controlled trials (RCTs) that compared ARP in periodontally compromised sockets to spontaneous socket healing. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool.

RESULTS

Five studies with 134 extraction sockets in 126 participants were included. Of these, ARP was performed in 77 sites, while the remaining sites were intentionally left to heal without any ARP treatment. The follow-up time varied between six and 12 months. Overall meta-analysis showed significant differences in changes in ridge height (mean difference (MD) -0.95; 95% confidence interval (CI) -1.43 to -0.47; P = 0.0001) and bone volume (MD -38.70; 95% CI -52.17 to -25.24; P < 0.0001) in favour of ARP. The use of ARP following extraction of periodontally compromised tooth was also associated with significantly less need for additional bone grafting at the time of implant placement.

CONCLUSIONS

Within the limitation of this review, ARP following extraction of periodontally compromised teeth may have short-term positive effects on alveolar ridge height and bone volume and minimize the need for additional augmentation procedures. However, the evidence is of very low to low certainty.

Effect of different thresholds on the accuracy of linear and volumetric analysis of native- and grafted-bone

The study aimed to evaluate the accuracy of Micro-CT in linear and volumetric measurements in native (NB) and grafted bone (GB) areas. A total of 111 biopsies of maxillary sinuses grafted with deproteinized bovine bone (DBB) in humans were evaluated. The linear measurements were performed to measure the length of the NB and GB. Furthermore, the amount of mineralized tissues at the NB and GB was performed. In the histomorphometry analysis the percentage of mineralized tissues at the NB and GB was obtained in two histological sections while the mineralized tissues were measure in the micro-CT varying the thresholds of the grayscale varying from 90-250 to 90-150 with 10 levels of variation between each one was applied. Then these data were correlated in order to check the higher r level between the histomorphometry and micro-CT thresholds intervals. The linear length of the NB was 2.44±0.91mm and 2.48±1.50mm, respectively, for micro-CT and histomorphometry (r =0.57), while the linear length of the GB was 3.63±1.66mm and 3.13±1.45mm, respectively, for micro-CT and histomorphometry (r =0.74) Histomorphometry showed 45.91±11.69% of bone in NB, and 49.57±5.59% of bone and biomaterial in the GB. The total volume of mineralized tissues that were closest to the histometric analysis were 43.75±15.39% in the NB (Threshold:90-240; r = 0.50) and 51.68±8.42% in the GB (Threshold:90-180; r =-0.028). The micro-CT analysis showed good accuracy in the linear analysis in both portions of the biopsies but for volumetric analysis just in NB.

Decoronation-induced infected alveolar socket defect rat model for ridge preservation

Current rat alveolar ridge preservation models have not been well standardized. In this study, we proposed decoronation-induced infected alveolar socket model of rat. The bilateral maxillary first molars (M1) of twenty-four rats were decoronized or extracted. After 2, 6, 10, and 14 weeks, bone and soft tissue changes at M1 and periodontal conditions of maxillary second (M2) and third molars (M3) were evaluated by micro-computed tomography and histological analysis. Additional eighteen rats with standardized size defects were grafted with Bio-Oss Collagen to compare with unmanipulated contralateral side. Decoronation preserved greater bone and soft tissue dimensions at M1, provided larger three-dimensional (3D) bone contour volume, but also promoted periodontal breakdown of M2 Histological results showed intense inflammatory cell infiltrations and severe bone resorption within M1 socket and at mesial aspect of M2. The critical dimensions to accommodate largest standardized defect at M1 were 2.2-2.3 mm at vertical bone height and 2.8-3.2 mm at alveolar crestal width. Bio-Oss Collagen could not fully preserve buccal or palatal bone height but could be beneficial in preserving ridge width in large alveolar defects. Collectively, if periodontally-involved alveolar bone defect is preferred, we suggest extracting M1 roots 6 weeks after decoronation to allow periodontitis to occur at M2. If standardized critical dimension defect is preferred, we suggest extracting M1 roots 2 weeks after decoronation, and creating defect in the middle of M1 site with size no larger than 2.7 mm diameter to its full depth.

Comparison of osseointegration in areas grafted with deproteinized bovine bone and native bone. A preclinical study

The aim of this study was to evaluate the osseointegration of implants placed in rat tibia sites grafted with Deproteinized Bovine Bone (DBB) and Native Bone (NB). Twenty-eight rats were divided into two groups according to the type of substrate in which the implants were to be placed: NB - implants placed in native bone; DBB - implants placed in areas grafted with DBB. In the DBB group, the bone defect was made and filled with the bone substitute 60 days before placing the implant. The animals were euthanized 15 or 45 days after implant placement. Osseointegration was assessed by the removal torque, volume of mineralized tissues around the implants (BV/TV), bone-implant contact (%BIC), and bone between threads (%BBT). The implants placed in NB presented higher removal torque (8.00 ± 1.26 Ncm vs. 2.33 ± 0.41 Ncm at 15 days and 22.00 ± 2.44 Ncm vs. 4.00 ± 1.41 Ncm at 45 days), higher %BV/TV (47.92 ± 1.54% vs. 33.33 ± 4.77% at 15 days and 70.06 ± 0.91% vs. 39.89±5.90%at 45 days), higher %BIC (39.68 ± 5.02% vs. 9.12 ± 5.56% at 15 days and 83.23 ± 4.42% vs. 18.81 ± 7.21% at 45 days), and higher %BBT (34.33 ± 5.42% vs. 13.24 ± 8.72% at 15 days and 82.33 ± 3.13% vs. 22.26 ± 8.27% at 45 days) than the implants placed in DBB grafted areas. The degree of osseointegration was lower in implants placed in the area grafted with DBB than in NB in rat tibias.

Comparison of the osseointegration of implants placed in areas grafted with HA/TCP and native bone

This study evaluated the osseointegration of implants in areas grafted with biphasic ceramic based on hydroxyapatite/β-tricalcium phosphate (HA/TCP) and in native bone (NB). Twenty-eight rats were randomly assigned into two groups of 14 animals each: HA/TCP group: implants installed in areas grafted with HA/TCP and NB group: implants installed in areas of native bone. Bone defects were made in both tibiae of the rats belonging to the HA/TCP group and then filled with this bone substitute. After 60 days, the rats were submitted to surgical procedures for implant placement in grafted areas in both tibiae in the HA/TCP group while the implants were installed directly in native bone in the NB group. The animals were euthanized 15 and 45 days, respectively, after the implant placement. Biomechanical (removal torque), microtomographic (volume of mineralized tissues around the implants), and histomorphometric (Bone-Implant contact-%BIC and bone area between the implant threads-%BBT) analyzes were conducted to assess the osseointegration process. The HA/TCP group showed lower values of removal torque, volume of mineralized tissue around the implants, lower %BIC, and %BBT compared to the NB group in both experimental periods. Osseointegration of implants placed in grafted areas with HA/TCP was lower compared to the osseointegration observed in native bone areas.

Radiographic assessment of deproteinized bovine bone mineral (DBBM) and collagen-stabilized DBBM for transalveolar sinus floor elevation: A 2-year retrospective cohort study

BACKGROUND

Theoretically, collagen-stabilized deproteinized bovine bone mineral (DBBM-C) has better operability compared with DBBM. DBBM-C avoids dispersing during the transalveolar sinus floor elevation (TSFE) because of its block shape.

PURPOSE

To evaluate radiological changes of using DBBM-C in TSFE.

MATERIALS AND METHODS

Patients who received TSFE using DBBM (Bio-Oss®) or DBBM-C (Bio-Oss® collagen) with simultaneous implantation were recruited. Graft bone height apically (aGH), endo-sinus bone gain (ESBG), and crest bone level (CBL) were assessed through panoramic radiograph and cone beam computed tomography (CBCT).

RESULTS

A total of 138 patients (138 implants) were retrospectively enrolled. After 2 years of implantation, the incidence of postoperative complications was 4.2% (95% CI: 0.9%-11.7%) and 4.5% (95% CI: 0.9%-12.7%) for DBBM and DBBM-C groups, respectively. Measured in panoramic radiograph, ΔaGH of DBBM-C (1.8 mm, SD: 1.4, 95% CI: 1.2-2.4, P = 0.044) group was significantly higher than that of DBBM (1.2 mm, SD: 1.4, 95% CI: 0.7-1.7) after 24 months. No significant differences for ΔCBL were noted during the entire observation period. Measured through CBCT, ESBG was 5.0 (SD: 1.8, 95% CI: 4.1-5.8) mm in DBBM group and 4.6 (SD: 1.6, 95% CI: 3.9-5.3) mm in DBBM-C group 24 months after implantation. The aGH value of DBBM-C group was significantly higher compared with DBBM in CBCT (OR = 1.4, 95% CI: 1.1-1.9, P = 0.020).

CONCLUSIONS

DBBM-C could achieve similar bone generation as DBBM in TSFE. Both materials could maintain aGH, ESBG, and CBL relatively stable 2 years after implantation.

Comparison of osseointegration in areas grafted with different osteoconductive biomaterials. Preclinical study

Abstract This study evaluated osseointegration in areas grafted with deproteinized bovine bone (DBB) and biphasic ceramic based on hydroxyapatite and beta-tricalcium phosphate (HA/TCP) in rat tibias. Noncritical bone defects were made in the tibias of 28 rats that were randomly assigned to 2 groups: DBB: DBB-filled defects and HA/TCP: HA/TCP-filled defects. Bone defects were made in the tibias bilaterally and filled with biomaterials. After 60 days, the implants were inserted, and the animals were euthanized 15 and 45 days after the implants were installed. Osseointegration was evaluated by biomechanical, microtomographic and histometric analysis. Implants installed in the defects filled with DBB presented higher removal torque forces (2.33 ± 0.51 Ncm vs. 1.50 ± 0.54 Ncm) and mineralized tissue volume around implants at 15 days (34.96 ± 3.68 % vs. 25.61 ± 2.95 %) and greater bone-implant contact (20.87 ± 8.28 % vs. 11.52 ± 7.42 %) and bone area within implant threads (26.83 ± 12.35 % vs. 11.98 ± 7.56 %) at 45 days compared to the measurements of implants in areas grafted with HA/TCP. Implants installed in defects in areas grafted with DBB had a better osseointegration pattern than implants placed in defects in areas grafted with HA/TCP.

Clinical evaluation of 3D printed nano-porous hydroxyapatite bone graft for alveolar ridge preservation: A randomized controlled trial

Background/purpose

Ridge resorption after tooth extraction may result in inadequate bone volume and unfavorable ridge architecture for ideal implant placement. The use of bone substitutes has been advocated to fill extraction sites and to enhance primary implant stability. This study was made to evaluate the clinical efficacy of novel 3D printed nano-porous hydroxyapatite (3DP HA, test group) in comparison to nano-crystalline bone graft (NanoBone®, control group) in alveolar ridge preservation prior to implant placement.

Materials and methods

Thirty patients were randomized into two groups following tooth extraction. All extracted sockets were filled with 3DP HA or NanoBone® and covered with a non-resorbable membrane. After four months, cone-beam computed tomography (CBCT) and intraoral scanner were used to measure dimensional changes of bone and soft tissue surface. Bone core specimens were harvested for histological analysis during implant osteotomy. Implant stability was assessed using a modified damping capacity analysis.

Results

At four months postoperatively, dimensional changes in soft tissue surface resorption were less in the test group than in the control group; however, alveolar bone resorption was the same in both groups. Histological analysis revealed new bone formation, residual graft and fibrous connective tissue in both groups. The average primary implant stability (IST) value for both groups was approximately 70. There was no statistically significant difference in all parameters between two groups (p > 0.05).

Conclusion

3DP HA could potentially be used as an alternative bone graft material for alveolar ridge preservation.

Metformin-Incorporated Gelatin/Nano-Hydroxyapatite Scaffolds Promotes Bone Regeneration in Critical Size Rat Alveolar Bone Defect Model

In this study, we fabricated gelatin/nano-hydroxyapatite/metformin scaffold (GHMS) and compared its effectiveness in bone regeneration with extraction-only, Sinbone, and Bio-Oss Collagen^® groups in a critical size rat alveolar bone defect model. GHMS was synthesized by co-precipitating calcium hydroxide and orthophosphoric acid within gelatin solution, incorporating metformin, and cross-linked by microbial transglutaminase. The morphology, characterization, and biocompatibility of scaffold were examined. The in vitro effects of GHMS on osteogenic gene and protein expressions were evaluated. In vivo bone formation was assessed in a critical size rat alveolar bone defect model with micro-computed tomography and histological examination by comparing GHMS with extraction-only, Sinbone, and Bio-Oss Collagen^®. The synthesized GHMS had a highly interconnected porous structure with a mean pore size of 81.85 ± 13.8 µm. GHMS exhibited good biocompatibility; promoted ALPL, RUNX2, SP7, BGLAP, SPARC and Col1a1 gene expressions; and upregulated the synthesis of osteogenic proteins, including osteonectin, osteocalcin, and collagen type I. In critical size rat alveolar bone defects, GHMS showed superior bone regeneration compared to extraction-only, Sinbone, and Bio-Oss Collagen^® groups as manifested by greater alveolar ridge preservation, while more bone formation with a lower percentage of connective tissue and residual scaffold at the defect sites grafted with GHMS in histological staining. The GHMS presented in this study may be used as a potential bone substitute to regenerate alveolar bone. The good biocompatibility, relatively fast degradation, interconnected pores allowing vascularization, and higher bioactivity properties of the components of the GHMS (gelatin, nHA, and metformin) may contribute to direct osteogenesis.

[Influencing Hard and Soft Tissue Changes Following Tooth Extraction]

Influencing Hard and Soft Tissue Changes Following Tooth Extraction Abstract. Influencing Hard and Soft Tissue Changes Following Tooth Extraction The loss of a tooth leads to the initiation of resorption processes and thus to the remodeling of the tissues of the alveolar process. At the hard tissue level, this resorption mainly affects the bundle bone at the buccal side of the extracted tooth and occurs most rapidly in the first weeks and months after extraction. Tissue changes occur not only at the level of the hard tissue (bone), but also at the level of the soft tissue. These changes lead to a significant loss of volume, especially at the buccal area of the alveolar ridge. They are responsible for a volume loss of the alveolar ridge contour of up to 50 %.

Effectiveness of a Nanohydroxyapatite-Based Hydrogel on Alveolar Bone Regeneration in Post-Extraction Sockets of Dogs with Naturally Occurring Periodontitis

Pathological mandibular fracture after dental extraction usually occurs in dogs with moderate to severe periodontitis. A nanohydroxyapatite-based hydrogel (HAP hydrogel) was developed to diminish the limitations of hydroxyapatite for post-extraction socket preservation (PSP). However, the effect of the HAP hydrogel in dogs has still not been widely investigated. Moreover, there are few studies on PSP in dogs suffering from clinical periodontitis. The purpose of this study was to evaluate the effectiveness of the HAP hydrogel for PSP in dogs with periodontitis. In five dogs with periodontitis, the first molar (309 and 409) of each hemimandible was extracted. Consequently, all the ten sockets were filled with HAP-hydrogel. Intraoral radiography was performed on the day of operation and 2, 4, 8 and 12 weeks post operation. The Kruskal-Wallis test and paired t-test were adopted for alveolar bone regeneration analysis. The results demonstrated that the radiographic grading, bone height measurement, and bone regeneration analysis were positively significant at all follow-up times compared to the day of operation. Moreover, the scanning electron microscopy with energy-dispersive X-ray spectroscopy imaging after immersion showed a homogeneous distribution of apatite formation on the hydrogel surface. Our investigation suggested that the HAP hydrogel effectively enhances socket regeneration in dogs with periodontitis and can be applied as a bone substitute for PSP in veterinary dentistry.

Soft-tissues stabilization after immediate implant; platform switch with supraperiosteal augmentation

The architecture around an oral implant pushes the clinicians for an equalization of biological and physiological requirements. An esthetic implant-supported restoration needs plethora of knowledge and expertise. Surgeon skills can be of use for correct tridimensional position of implant in the extraction socket, shaped abutment contours, and anatomical final crown. An immediate implant placement for a fresh socket requires existing oral parameters judgment and evidence-based treatment plan. They are hard- and soft-tissue relationship, gingival biotype, and the tooth position. In this article, we describe a case of immediate implant placement, provisional crown, bovine bone contraction, soft-tissue collapse, and its management.

Bone Regeneration of a 3D-Printed Alloplastic and Particulate Xenogenic Graft with rhBMP-2

This study aimed to evaluate the bone regeneration capacity of a customized alloplastic material and xenograft with recombinant human bone morphogenetic protein-2 (rhBMP-2). We prepared hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic bone blocks made using a 3D printing system and added rhBMP-2 to both materials. In eight beagle dogs, a total of 32 defects were created on the lower jaws. The defective sites of the negative control group were left untreated (N group; 8 defects), and those in the positive control group were filled with particle-type Bio-Oss (P group; 12 defects). The defect sites in the experimental group were filled with 3D-printed synthetic bone blocks (3D group; 12 defects). Radiographic and histological evaluations were performed after healing periods of 6 and 12 weeks and showed no significant difference in new bone formation and total bone between the P and 3D groups. The 3D-printed custom HA/TCP graft with rhBMP-2 showed bone regeneration effects similar to that of particulate Bio-Oss with rhBMP-2. Through further study and development, the application of 3D-printed customized alloplastic grafts will be extended to various fields of bone regeneration.

LED photobiomodulation therapy combined with biomaterial as a scaffold promotes better bone quality in the dental alveolus in an experimental extraction model

A bone scaffold added to the dental alveolus immediately after an extraction avoids bone atrophy and deformity at the tooth loss site, enabling rehabilitation with implants. Photobiomodulation accelerates bone healing by stimulating blood flow, activating osteoblasts, diminishing osteoclastic activity, and improving the integration of the biomaterial with the bone tissue. The aim of the present study was to evaluate the effect of photobiomodulation with LED at a wavelength of 850 nm on bone quality in Wistar rats submitted to molar extraction with and without a bone graft using hydroxyapatite biomaterial (Straumann® Cerabone®). Forty-eight rats were distributed among five groups (n = 12): basal (no interventions); control (extraction) (basal and control were the same animal, but at different sides); LED (extraction + LED λ = 850 nm); biomaterial (extraction + biomaterial), and biomaterial + LED (extraction + biomaterial + LED λ = 850 nm). Euthanasia occurred at 15 and 30 days after the induction of the extraction. The ALP analysis revealed an improvement in bone formation in the control and biomaterial + LED groups at 15 days (p = 0.0086 and p = 0.0379, Bonferroni). Moreover, the LED group had better bone formation compared to the other groups at 30 days (p = 0.0007, Bonferroni). In the analysis of AcP, all groups had less resorption compared to the basal group. Bone volume increased in the biomaterial, biomaterial + LED, and basal groups in comparison to the control group at 15 days (p < 0.05, t-test). At 30 days, the basal group had greater volume compared to the control and LED groups (p < 0.05, t-test). LED combined with the biomaterial improved bone formation in the histological analysis and diminished bone degeneration (demonstrated by the reduction in AcP), promoting an increase in bone density and volume. LED may be an important therapy to combine with biomaterials to promote bone formation, along with the other known benefits of this therapy, such as the control of pain and the inflammatory process.

Effects of hyaluronic acid and deproteinized bovine bone mineral with 10% collagen for ridge preservation in compromised extraction sockets

BACKGROUND

The aim of this study was to evaluate the efficacy of deproteinized bovine bone mineral with 10% collagen (DBBM-C) soaked with hyaluronic acid (HA) for ridge preservation in compromised extraction sockets.

METHODS

Bilateral third, fourth premolars and first molar were hemisected, distal roots were extracted, and then combined endodontic periodontal lesion was induced in the remaining mesial roots. After 4 months, the mesial roots were extracted and the following four treatments were randomly performed: Absorbable collagen sponge (ACS), ACS soaked with HA (ACS+HA), ridge preservation with DBBM-C covered with a collagen membrane (RP), ridge preservation with DBBM-C mixed with HA and covered with a collagen membrane (RP+HA). Animals were sacrificed at 1 and 3 months following treatment. Ridge dimensional changes and bone formation were examined using microcomputed tomography, histology, and histomorphometry.

RESULTS

At 1 month, ridge width was significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups, while the highest proportion of mineralized bone was observed in ACS+HA group. At 3 months, ridge width remained significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups. ACS+HA and RP+HA treatments featured the highest proportion of mineralized bone and bone volume density compared with the other groups. No statistical difference was observed between ACS+HA and RP+HA treatments.

CONCLUSIONS

Ridge preservation with the mixture DBBM-C/HA prevented dimensional shrinkage and improved bone formation in compromised extraction sockets at 1 and 3 months.

Association of hyaluronic acid with a deproteinized bovine graft improves bone repair and increases bone formation in critical-size bone defects

BACKGROUND

This study is designed to evaluate the potential of different formulations of hyaluronic acid (HA) to improve new bone formation in critical-size calvaria defect (CSD) when combined with a deproteinized bovine graft (DBG) material.

METHODS

Thirty male rats were used. A 5-mm-diameter CSD was created and three experimental groups (n = 10) were randomly assigned based on the treatments performed. Group DBG: CSD filled with a DBG; group DBG/LV: CSD filled by the combination of DBG and HA in a low-viscosity crosslinking agent; group DBG/HV: CSD filled by the combination of DBG and HA in a high-viscosity crosslinking agent. Animals were euthanized 30 days postoperatively. Histological, histometric (percentage of newly formed bone [PNFB], percentage of remaining graft particles, histochemical, and immunohistochemical (bone morphogenetic protein 2/4 [BMP2/4], osteocalcin [OCN], and tartrate-resistant acid phosphatase [TRAP]) analyses were performed.

RESULTS

The highest PNFB was observed in DBG/HV when compared with the other groups (P ≤0.05). DBG/LV and DBG/HV presented almost no inflammatory cells. In contrast, inflammation was observed in group DBG. Extensive resorption of graft particles was observed in group DBG, which was not present in DBG/LV and DBG/HV as confirmed by the larger size of the particles (P ≤0.05). BMP2/4 and OCN immunolabeling were higher in DBG/HV when compared with group DBG (P ≤0.05). Increased number of TRAP-positive cells was observed in DBG/LV and DBG/HV (P ≤0.05). Lower percentage of mature collagen fibers was observed in DBG/HV (P ≤0.05).

CONCLUSION

The combination of HA in a high-viscosity crosslinking agent with DBG improves the bone repair process and increases the amount of newly formed bone towards CSDs in rat calvaria.

Peri-implant tissue changes at sites treated with alveolar ridge preservation in the aesthetic zone: Twenty-two months follow-up of a randomized clinical trial

AIM

To compare tissue changes at implant sites previously treated with two biomaterials for alveolar ridge preservation (ARP) in the aesthetic zone, 1 year after restoration.

MATERIALS AND METHODS

Sixty-six participants were treated with ARP using demineralized bovine bone mineral (DBBM) or DBBM +10% of collagen (DBBM-C), both covered with a collagen matrix (CM). Dental implants were placed, and definitive crowns were installed. Silicon impressions were taken before tooth extraction (T0), 2 weeks after crown insertion (T1) and 1 year after restoration (T2). Mid-facial mucosal level change (MLC), soft tissue thickness changes (TT), and marginal bone loss (MBL) were analysed using inter-group comparisons.

RESULTS

Fifty-four participants were included in the analysis. The mid-facial level change between T0-T1 and T1-T2 showed no statistical difference between DBBM and DBBM-C. Between T0 and T1 for soft tissue thickness, DBBM performed significantly better at 3 and 5 mm below the mucosal margin. From T1 to T2, no significant differences between groups were found at any level for soft tissue thickness and MBL.

CONCLUSION

At the aesthetic zone, advanced recession from tooth extraction to crown placement can be expected at sites treated with ARP regardless of biomaterial used. However, after crown insertion, tissue stability can be predicted.

Effect of alveolar ridge preservation on clinical attachment level at adjacent teeth: A randomized clinical trial

PURPOSE

To test whether or not alveolar ridge preservation (ARP) changes the clinical attachment level (CAL) at adjacent teeth of extraction sockets after 6 months.

MATERIAL AND METHODS

Seventeen patients requiring bilateral tooth extractions of the upper molars were recruited. After tooth extraction, the sockets were randomly allocated to two groups applying a split-mouth design: (1) ARP using deproteinized bovine bone mineral containing 10% collagen (DBBM-C) covered by a collagen membrane and (2) spontaneous healing (control). CAL, probing pocket depth (PD), bleeding on probing (BOP), gingival recession (REC), and bone levels were evaluated at the adjacent teeth of the extraction sockets at baseline and after 6 months of follow-up.

RESULTS

A total of 14 patients were available for reexamination. From baseline to 6 months of follow-up mean CAL changes of all six sites at adjacent teeth of the extraction sockets amounted to -0.23 ± 0.65 mm (gain) in ARP group and 0.05 ± 0.86 mm (loss) in the control group with significant differences in favor of ARP (p = 0.04). The CAL gain was significantly more favorable at mesiopalatal sites (p = 0.01). Consistently, the mean reduction of PD of all six sites amounted to -0.68 ± 0.84 mm in ARP and -0.34 ± 0.74 mm in the control group (intergroup p = 0.02). The PD reduction was significant (p = 0.001) at the mesiopalatal sites in ARP. BOP, REC, and bone levels showed no significant differences between the groups (intergroup p > 0.05).

CONCLUSION

Although ARP with DBBM-C revealed a trend toward CAL gain and PD reduction at adjacent teeth of extraction sites, these adjunctive benefits seem to be clinically negligible.

UV Light-Generated Superhydrophilicity of a Titanium Surface Enhances the Transfer, Diffusion and Adsorption of Osteogenic Factors from a Collagen Sponge

It is a significant challenge for a titanium implant, which is a bio-inert material, to recruit osteogenic factors, such as osteoblasts, proteins and blood effectively when these are contained in a biomaterial. The objective of this study was to examine the effect of ultraviolet (UV)-treatment of titanium on surface wettability and the recruitment of osteogenic factors when they are contained in an atelocollagen sponge. UV treatment of a dental implant made of commercially pure titanium was performed with UV-light for 12 min immediately prior to the experiments. Superhydrophilicity on dental implant surfaces was generated with UV-treatment. The collagen sponge containing blood, osteoblasts, or albumin was directly placed on the dental implant. Untreated implants absorbed only a little blood from the collagen sponge, while the UV-treated implants absorbed blood rapidly and allowed it to spread widely, almost over the entire implant surface. Blood coverage was 3.5 times greater for the UV-treated implants (p < 0.001). Only 6% of the osteoblasts transferred from the collagen sponge to the untreated implants, whereas 16% of the osteoblasts transferred to the UV-treated implants (p < 0.001). In addition, a weight ratio between transferred albumin on the implant and measured albumin adsorbed on the implant was 17.3% in untreated implants and 38.5% in UV-treated implants (p < 0.05). These results indicated that UV treatment converts a titanium surface into a superhydrophilic and bio-active material, which could recruite osteogenic factors even when they were contained in a collagen sponge. The transfer and subsequent diffusion and adsorption efficacy of UV-treated titanium surfaces could be useful for bone formation when titanium surfaces and osteogenic factors are intervened with a biomaterial.

Alveolar ridge regeneration in two-wall-damaged extraction sockets of an in vivo experimental model

Aim

To determine the healing outcome following grafting with deproteinized porcine bone mineral (DPBM) with or without collagen membrane coverage in two‐wall (both buccal and lingual)‐damaged extraction sockets.

Materials and methods

Distal roots of three mandibular premolars in six beagle dogs were extracted, and the whole buccal and lingual bony walls were surgically removed. Three treatment protocols were then applied according to the following group allocation: no graft (None), grafting DPBM (BG), and grafting DPBM with coverage by a collagen membrane (BG + M). Two observational periods (2 and 8 weeks) were used with the split‐mouth design, and quantitative and qualitative analyses were performed by microcomputed tomography and histology.

Results

The dimensions of the alveolar ridge at both grafted sites (BG and BG + M) remained similar to those of the pristine ridge in the histologic and radiographic analyses, whereas the ungrafted sites (None) collapsed both vertically and horizontally. Both grafting protocols produced substantial bony regeneration, but the addition of a covering membrane enhanced the proportion of mineralized tissue within the augmented area, and the BG + M group also showed a significantly larger area of regenerated ridge than the None group (p < .05).

Conclusions

Bone grafting with collagen membrane can maintain the alveolar ridge dimensions with substantial bone regeneration in a two‐wall‐damaged extraction socket.

Accelerating Socket Repair via WNT3A Curtails Alveolar Ridge Resorption

Tooth extraction triggers alveolar ridge resorption, and when this resorption is extensive, it can complicate subsequent reconstructive procedures that use dental implants. Clinical data demonstrate that the most significant dimensional changes in the ridge occur soon after tooth extraction. Here, we sought to understand whether a correlation existed between the rate at which an extraction socket heals and the extent of alveolar ridge resorption. Maxillary molars were extracted from young and osteoporotic rodents, and quantitative micro-computed tomographic imaging, histology, and immunohistochemistry were used to simultaneously follow socket repair and alveolar ridge resorption. Extraction sockets rapidly filled with new bone via the proliferation and differentiation of Wnt-responsive osteoprogenitor cells and their progeny. At the same time that new bone was being deposited in the socket, tartrate-resistant acid phosphatase-expressing osteoclasts were resorbing the ridge. Significantly faster socket repair in young animals was associated with significantly more Wnt-responsive osteoprogenitor cells and their progeny as compared with osteoporotic animals. Delivery of WNT3A to the extraction sockets of osteoporotic animals restored the number of Wnt-responsive cells and their progeny back to levels seen in young healthy animals and accelerated socket repair in osteoporotic animals back to rates seen in the young. In cases where the extraction socket was treated with WNT3A, alveolar ridge resorption was significantly reduced. These data demonstrate a causal link between enhancing socket repair via WNT3A and preserving alveolar ridge dimensions following tooth extraction.

Comparative in vitro study of commercially available products for alveolar ridge preservation

BACKGROUND

Ridge preservation is performed by placing a biocompatible product, following tooth extraction, to maintain bone volume. However, current ridge preservation therapies do not always maintain the volume required for future implant placement. Variations in surgical technique and material selection contribute to determining clinical outcomes. The wide variety of grafting materials available and conflicting efficacy reports make selecting the appropriate graft materials challenging. To investigate how different commercially available ridge preservation products might perform clinically: Helistat (collagen control) (Material 1), OsteoGen Plug (Material 2), Bio-Oss Collagen (Material 3), and J-Bone (native bone) (Material 4) were evaluated.

METHODS

These products underwent field emission scanning electron microscopy, microcomputed tomography, helium pycnometry, and infrared spectra analysis. Human osteosarcomas were incubated on products and proliferation was monitored with CCK-8 and visualized with confocal microscopy. Scaffold osteoconductivity was evaluated through the cellular production of proteins osteocalcin, osteonectin, and osteopontin.

RESULTS

Results indicated that products varied in porosity and pore interconnectivity. Although Material 3 was chemically similar to Material 4, Material 2 demonstrated significantly better biocompatibility. Functionally, Material 1 and Material 2 elicited higher osteonectin release than Material 3 and Material 4 which suggests the latter products suppress endogenous osteonectin secretion. Furthermore, osteopontin secretion was minimal for all products, while osteocalcin was elevated. This seems to suggest that high levels of mineralization might be deleterious for bone regeneration.

CONCLUSIONS

Although all products are marketed as effective preservation products, the results demonstrated high variability in physical, chemical, and biological effects; however, this study suggests a product with higher ratio of collagen to mineral component may have the most desirable effects for the use in alveolar ridge preservation.

Evaluation of healing at molar extraction sites with ridge preservation using a non-resorbable dense polytetrafluoroethylene membrane: A four-arm cohort prospective study

Objectives

To examine ridge dimensional changes and histologic parameters of healing when ridge preservation (RP) was performed at molar sites using dense polytetrafluoroethylene (dPTFE) membrane alone, without a bone graft.

Material and Methods

Eighteen patients had molar extraction and RP using dPTFE membrane alone. Ridge dimensions were measured using two standardized cone beam computerized tomography (CBCT) scans taken within 72 h and 3 months following extraction. Following a 3‐month healing period, an implant osteotomy was prepared using a trephine drill and bone cores were collected for histological analysis. Four‐arm analyses were performed using data from three previously published study arms of the same research group.

Results

There was a significant change in the buccal ridge height between the four groups at all aspects of the socket. Alveolar ridge width reduction at 3 mm from crest for all aspects (mesial, midpoint, distal) of the socket showed statistically significant difference for dPTFE alone group compared to the other three groups. Percentage of vital bone formation (62.10%) was significantly greater in dPTFE alone group compared to the other groups.

Conclusions

RP using dPTFE membrane alone in molar sites with intact socket walls showed successful outcomes in maintaining ridge dimensions and in histologic wound healing.

Developments for Collagen Hydrolysate in Biological, Biochemical, and Biomedical Domains: A Comprehensive Review

The collagen hydrolysate, a proteinic biopeptide, is used for various key functionalities in humans and animals. Numerous reviews explained either individually or a few of following aspects: types, processes, properties, and applications. In the recent developments, various biological, biochemical, and biomedical functionalities are achieved in five aspects: process, type, species, disease, receptors. The receptors are rarely addressed in the past which are an essential stimulus to activate various biomedical and biological activities in the metabolic system of humans and animals. Furthermore, a systematic segregation of the recent developments regarding the five main aspects is not yet reported. This review presents various biological, biochemical, and biomedical functionalities achieved for each of the beforementioned five aspects using a systematic approach. The review proposes a novel three-level hierarchy that aims to associate a specific functionality to a particular aspect and its subcategory. The hierarchy also highlights various key research novelties in a categorical manner that will contribute to future research.

Early implant placement in ridge preserved extraction sockets: A pre-clinical in vivo study

OBJECTIVES

The aim was to analyse the outcomes of early implant placement after 6 and 12 weeks of healing in ridge preserved sites in a canine model.

MATERIALS AND METHODS

Implants were placed in second maxillary incisors sites in 9 dogs 6 weeks after grafting of the sockets with 90% deproteinized bovine bone mineral in 10% collagen matrix (DBBMC) and closure with resorbable type I/III porcine collagen matrix (PCM). The implants were randomly assigned to 6 (T6) and 12 (T12) weeks of healing.

RESULTS

The percentage of bone-to-implant contact (%BIC), old bone, new bone and residual DBBMC was similar between T6 and T12. In relation to the implant shoulder (IS), the original bone crest (IS-ROB) was more apical on the buccal than the palatal side. The regenerated bone crest (IS-C) and IS-ROB were similar between groups. However, the distance from IS to first bone-to implant contact (IS-fBIC) was significantly less in T12 compared with T6 (p = .022; Wilcoxon signed-rank test). The bucco-palatal ridge dimensions between T6 and T12 were similar.

CONCLUSIONS

This study confirms that implants can successfully be placed early in ridge preserved maxillary second incisor sites and are osseointegrated by 6 weeks. There were significantly lower IS-fBIC values at 12 weeks than at 6 weeks on the buccal aspect. The original buccal bone crest underwent greater corono-apical resorption than the palatal crest. The %BIC, relative proportions of mineralized tissues and dimensions of the alveolar ridge demonstrated stability between 6 and 12 weeks of healing.

Assessment of Bone Regeneration Using Tooth Ash and Injectable Platelet Rich Fibrin: A Microcomputed Tomographic (CT) Analysis

Introduction: One of the main challenge of bone graft or socket preservation in particular is to get good quality and quantity of bone in short time prior to implant bed preparation. The buccal bone at the crest of the ridge is a very thin bone and usually resorb faster than the rest of alveolar bone which may hinder an optimum dento-osseous implant insertion. The purpose of this study will be to assess the bone regeneration capabilities of Tooth Ash Particles (TAP) with injectable Plasma Rich Fibrin (i-PRF) and Tooth Ash Particles (TAP) alone at defects created in the goat mandible bone using micro-computed tomographic (micro-CT). Materials and Methods: A total, 54 bone defect (5 mm × 8 mm) were performed in the 18 goats. The created defect received different treatment (Tx): Tx.A: Unfilled defect (allow natural bone regeneration; Tx.B: Tooth Ash particle (TAP) alone; Tx.C: Tooth Ash + injectable PRF (TAP/i-PRF). Six goats, were sacrificed at different time points:Group 1: at 2nd week, Group2: at 5th week and Group3 at 8th week. The newly formed bone (NFB) was analyzed using micro-CT at different time points. Quantitative and qualitative assessment were carried out namely; the volume of new bone formation (NF-BV) within the defect and its mineral density (NF-BMD), Trabecular Thickness (Tb Th), Trabecular Number (Tb N) and Trabecular Separation (Tb Sp). Result: By 8th week, the mean NF-BV was 69.482 ± 6.554 mm3 (cubic millimeter), 65.872±6.804 mm3, 26.820±14.643 mm3, while the mean NF-BMD was 0.417±0.119g/mm3, 0.786±0.036 g/mm3, 0.805±0.033 g/mm3 for the defects which received Tx.C, Tx.B and Tx.A respectively. At 8th weekTb Th of NFB was 0.612±0.168, 0.913±0.112, and 0.701 ±0.126, Trabecular Number of NFB was 2.062±0.946, 1.002±0.155, and 1.816±2.042 and, Trabecular Separation of NFB was 0.330 ±0.131, 0.559 ±0.110, and 0.495 ±0.258 for the defects which received Tx.A, Tx.B and Tx.C respectively. Conclusion: Micro-CT study demonstrated that tooth ash particles mixed with injectable Platelet Rich Fibrin (i-PRF) on mandibular bone defect in goat’s model, resulting in new bone with significantly higher volume, mineral density and less remodeling rate when compared with normal bone regeneration of unfilled defects.

Ridge preservation of a novel extraction socket applying Bio-Oss® collagen: An experimental study in dogs

Background

Bio-Oss® collagen (BC) has been used in clinical applications for years but the ridge preservation property of BC remains controversial. There is no animal model accurately simulates the extraction socket in people. The aim of this study was to assess the ridge preservation of a novel extraction sockets with a thin buccal plate using BC.

Materials and methods

Two beagle dogs were used to assess the characterization of the novel extraction socket. The width and height of the socket were measured and biopsies of the socket were collected for histologic examination. Four beagle dogs were used to assess the ridge preservation property of BC. BC was placed in the socket and socket left untreated was set as control group (CT). Cone-beam computed tomography analysis, histological examination, and micro-CT analysis were used to evaluate the ridge preservation.

Results

The novel extraction socket had obvious larger volume with a markedly narrow buccal wall than mandible extraction sockets. At 12 weeks, the width of the crest of the alveolar ridge preservation ratios was 34% for the CT and 82% for the BC. BC group had larger socket volume compare to CT group. BC group had a significant higher bone density in the middle and apical areas of the alveolar bone. Socket placed with BC showed significantly less vertical bone loss compared with CT group.

Conclusion

Extraction site with a significantly larger dimension and a very thin buccal plate was established. Extraction sockets filled with BC exhibit excellent maintenance of alveolar bone volume.

Bone Graft Materials for Alveolar Bone Defects in Orthodontic Tooth Movement

Clinically, orthodontic tooth movement (OTM) across the narrow alveolar ridge area inevitably entails some adverse reactions such as limited movement and periodontal tissue damage. Hence, it is essential to reconstruct the morphology of the alveolar crest before the tooth movement. Unlike the routine reconstruction of alveolar ridge in the field of implant, the orthodontic practices are distinctive, which require dental movement across the constructed alveolar ridge with safety and stability. Herein, we addressed the pros and cons of reconstruction of the defected orthodontic alveolar ridge with different bone graft materials. Attention is also paid to other factors such as the postgraft initiation time of OTM that can substantially influence the bone reconstruction and tooth movement effect. Rather, considering the lack of a unified standard in orthodontic clinics related to bone reconstruction for OTM, we provide some recommendations and guidance for OTM through alveolar ridge defect area.

Comparison of extraction sites versus artificial defects with xenogenic bone substitute in minipigs

Objectives

The preclinical evaluation of bone substitutes is frequently performed in artificially created defects. However, such defects do not reflect the predominant clinical application of bone substitutes for socket preservation. Hence, the goal of this animal study was to compare the performance of a xenogenic bone substitute in extraction sites versus artificial defects.

Material and Methods

Four study sites each were created in the mandibles of four minipigs in the region of the third premolars and first molars, respectively. On one side, fresh extraction sockets were established while contralaterally trephine defects were created in healed alveolar bone. All sites were augmented using a particulate xenogenic bone substitute, covered by resorbable membranes and allowed to heal for 12 weeks. The amounts of new bone, non‐bone tissue and remaining bone substitute granules were quantified through histological and micro‐CT analysis. Comparative statistics were based on t‐tests for two samples and ANOVA with the level of significance set at α = 0.05.

Results

Histomorphometric data from only two animals could be quantitatively analyzed due to difficulty with identifying the surgical sites. The percentage of newly formed bone ranged between 53.2% ± 5.6% for artificial defects and 54.9% ± 12.4% for extraction sites. With the exception of ANOVA indicating a greater amount of non‐bone tissue in extraction sites as compared to artificial sites (p = 0.047), no statistically significant differences were observed. Micro‐CT scans showed patterns similar to the ones observed in histomorphometry. As extraction sites could be identified only in two micro‐CT reconstructions, quantitative assessment was not undertaken.

Conclusions

Despite the comparable performance of bone substitute material in artificial defects and extraction sites found here, the data gathered with this experiment was insufficient for showing equivalence of both approaches.

Comparative analysis of dimensional alterations following extraction of maxillary molars using three-dimensional images' superimposition: a CBCT study

The aims of this study were to (i) evaluate the bone alterations following maxillary molar extraction and (ii) identify the factors associated with bone alterations using a tomographic analysis. Cone Beam Computer Tomographies (CBCTs) of 17 subjects with 25 maxillary molars were analyzed, before and, in average, 12 months following extraction. Fifty CBCTs were segmented as 3D models that were used as reference for analysis. Cross-sectional planes were established to measure the dimensional changes in the vertical, horizontal aspects, and the area of the alveolar bone. Associations between root divergence, initial bone location related to the maxillary sinus, and the thickness of buccal and palatal bone at baseline was assessed using mixed-effect models. Overall, the average reduction in vertical bone height was 35.23% (2.61 ± 1.76 mm). The mean reduction of area of alveolar process and horizontal bone width were 18.89% (56.08 ± 44.23 mm²) and 65.10% (8.33 ± 4.51 mm), respectively. There was a marginal significant association between horizontal bone changes and the thickness of palatal bone (p = 0.05). The results of the present study indicated that following maxillary molar extraction, significant dimensional changes occur in both the vertical and horizontal directions. The vertical changes were mainly attributed to remodeling on the coronal aspect of the alveolar ridge and sinus pneumatization was rare.

Dimensional changes of the maxillary sinus augmented with a collagenated synthetic bone block or synthetic bone particulates: A pre-clinical study in rabbits

OBJECTIVE

To compare the efficacy of a collagenated synthetic bone substitute (C-SBS) to a particulated synthetic bone substitute (P-SBS) in volume maintenance and new bone formations in a rabbit sinus model.

MATERIALS AND METHODS

Either C-SBS or P-SBS was grafted in both sinuses of 16 rabbits. Four (N = 8) or 12 (N = 8) weeks after the surgery, total augmented volume (TAV) and area (TAA), as well as new bone volume (NBV) and area (NBA), were statistically compared by radiographic and histomorphometric analyses (p < .05).

RESULTS

The differences in TAV, NBV, TAA and NBA between C-SBS and P-SBS groups at 4 weeks were not statistically significant. The TAV (267.13 ± 62.08 vs. 200.18 ± 40.32 mm³ ) and NBV (103.26 ± 10.50 vs. 71.10 ± 7.58 mm³ ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05). The TAA (19.36 ± 2.88 vs. 14.48 ± 2.08 mm² ) and NBA (5.43 ± 1.20 vs. 3.76 ± 0.78 mm² ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05).

CONCLUSIONS

Collagenated synthetic bone substitute grafted in rabbit sinuses demonstrated more favourable outcomes across all outcome measures compared to P-SBS at 12 weeks.