Ridge regeneration of damaged extraction sockets using rhBMP-2: an experimental study in canine

In vivo experimental study comparing alveolar ridge preservation versus guided bone regeneration after unassisted socket healing at intact and damaged sites in narrow alveolar ridges

BACKGROUND

To compare bone regeneration and dimensional alteration of alveolar ridge at intact and damaged extraction sockets after alveolar ridge preservation (ARP) and implant placement versus unassisted socket healing followed by guided bone regeneration (GBR) with simultaneous implant placement.

METHODS

In 6 beagle dogs, 3 types of extraction sockets in the mandible were created: (1) intact sockets, (2) 1-wall defect sockets and (3) 2-wall defect sockets. The sockets were allocated to undergo either (1) ARP and implant placement 8 weeks later (ARP group) or (2) GBR with simultaneous implant placement after 8 weeks of unassisted socket healing (GBR group). After an additional healing period of 8 weeks, bone regeneration and dimensional changes were evaluated radiographically and histologically.

RESULTS

GBR showed superior bone formation and greater bone gains compared to ARP, regardless of the initial extraction-socket configuration. Although ARP maintained the preexisting alveolar ridge dimensions, peri-implant bone defects were still detected at 8 weeks of follow-up. Histomorphometric analyses confirmed that GBR increased dimensions of the alveolar ridge compared to baseline, and the augmentation and bone regeneration were greater with GBR than with ARP.

CONCLUSION

Early implant placement with ARP can mitigate alveolar ridge changes in the narrow alveolar ridge. However, early implant placement with simultaneous GBR creates the conditions for enhanced bone regeneration around the implant and greater ridge augmentation compared to ARP, irrespective of the extraction-socket configuration.

Alveolar ridge preservation of two-wall bone defects using mineralized dentin matrix: An experimental pre-clinical study

OBJECTIVES

To study bone healing of two-wall bone defects after alveolar ridge preservation using mineralized dentin matrix.

MATERIALS AND METHODS

After distal roots extraction of second and fourth premolars (P2, P4) on one lateral mandible in 12 beagles, two-wall bone defects (5 × 5 × 5 mm) were surgically created distally to the remaining mesial roots of P2 and P4. A total of 24 sites were randomly allocated to three groups (implant material- time of execution): mineralized dentin matrix (MDM)-3 m (MDM + collagen membrane; 3 months), MDM-6 m (MDM particles + collagen membrane; 6 months), and C-6 m (collagen membrane only; 6 months). Clinical, radiographic, digital, and histological examinations were performed 3 and 6 months after surgery.

RESULTS

The bone healing in MDM groups were better compared to Control group (volume of bone regenerated in total: 25.12 mm3 vs. 13.30 mm3, p = .046; trabecular volume/total volume: 58.84% vs. 39.18%, p = .001; new bone formation rate: 44.13% vs. 31.88%, p = .047). Vertically, the radiological bone level of bone defect in MDM-6 m group was higher than that in C-6 m group (vertical height of bone defect: 1.55 mm vs. 2.74 mm, p = .018). Horizontally, no significant differences in buccolingual bone width were found between MDM and C groups at any time or at any level below the alveolar ridge. The percentages of remaining MDM were <1% in both MDM-3 m and MDM-6 m groups.

CONCLUSIONS

MDM improved bone healing of two-wall bone defects and might be considered as a socket fill material used following tooth extraction.

Ridge preservation using a self-retaining block type bone substitute for extraction sockets with buccal dehiscence defects - A preclinical study

OBJECTIVE

To evaluate the effect of a self-retaining block-type bone substitute (srBB) on the dimensional stability of the horizontal ridge width at the coronal level in a buccal dehiscence model.

MATERIALS AND METHODS

Four box-shaped bone defects with a buccal dehiscence were surgically prepared in the partially edentulous mandible (n = 6). Experimental biomaterials were randomly assigned to each site: (1) Control group: no treatment, (2) particle-type bone substitute (PBS) group, (3) collagenated soft block bone substitute (csBB) group, and (4) self-retaining synthetic block bone (srBB) group. In all grafted groups, a collagen membrane covered the biomaterials. At 16 weeks, clinical, histological, and radiographic analyses were performed.

RESULTS

Three of the six blocks in the srBB group became exposed and fell out during the first week after surgery. Therefore, the remaining three specimens were renamed RsrBB group. The RsrBB group showed an increase horizontal ridge compared to the pristine bone width at 2-4 mm below the CEJ, while the other groups showed resorption (augmented width at 2 mm below: 4.2, 42.4, 36.2, and 110.1% in the control, PBS, csBB, and RsrBB groups, respectively). The mineralized bone area was largest in the RsrBB group (4.74, 3.44, 5.67, and 7.77 mm2 in the control, PBS, csBB, and RsrBB groups, respectively.).

CONCLUSIONS

The srBB group demonstrated the highest volume stability at the coronal level. These findings would potentially suggest that self-retaining block bone substitute might be a good candidate for alveolar ridge preservation.

Effectiveness of a collagen matrix seal and xenograft in alveolar ridge preservation: an experimental study in dogs

Majority of previous studies on alveolar ridge preservation (ARP) used collagen membranes as barrier membranes, and further evidence for ARP in dehiscent extraction sockets with a deproteinized bovine bone mineral (DBBM) and matrix is needed. The aim of this study is to assess the impact of non-cross linked collagen membranes (membrane) and crosslinked collagen matrices (matrix) on ARP using DBBM in extraction sockets with buccal dehiscence. In six mongrel dogs, the mesial roots of three mandibular premolars (P2, P3, and P4) were extracted 1 month after dehiscence defect induction. Two experimental groups were randomly assigned: (1) DBBM with a membrane (DBBM/membrane group) and (2) DBBM with a matrix (DBBM/matrix group). Three-dimensional (3D) volumetric, microcomputed tomography (μCT), and histologic analyses were performed to assess the ridge preservation. Both groups were effective to maintain the ridge width (p > 0.05), and the DBBM/matrix group showed more favorable soft tissue regeneration and bone quality in the histological analysis (p = 0.05). Based on these results, DBBM/matrix could be better choice for ARP in cases of buccal dehiscence defects.

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.

Alveolar ridge preservation of damaged or periodontally compromised extraction sockets with bovine- and porcine-derived block bone substitutes: A retrospective case-control study

PURPOSE

Alveolar ridge preservation (ARP) was introduced to minimize postextraction alveolar bone loss and extraction socket remodeling; however, current knowledge of the ARP procedure for nonintact extraction sockets is still limited and inconclusive. This retrospective study aimed to evaluate the difference between using deproteinized bovine bone mineral with 10% collagen (DBBM-C) and deproteinized porcine bone mineral with 10% collagen (DPBM-C) when performing ARP procedures in damaged or periodontally compromised extraction sockets based on clinical, radiographic, and profilometric outcomes.

METHODS

In total, 108 extraction sockets were grafted with 67 DBBM-C and 41 DPBM-C. Changes in radiographic (horizontal width and vertical height) and profilometric outcomes were measured after the ARP procedure and before the implant surgery. Postoperative discomfort (including the severity and duration of pain and swelling), early wound healing outcomes (including spontaneous bleeding and persistent swelling), implant stability, and treatment modalities for implant placement were also assessed.

RESULTS

Radiographically, the DBBM-C group decreased by -1.70 ± 2.26 mm (-21.50%) and - 1.39 ± 1.85 mm (-30.47%) horizontally and vertically, and the corresponding DPBM-C group decreased by -1.66 ± 1.80 mm (-20.82%) and -1.44 ± 1.97 mm (-27.89%) horizontally and vertically at an average of 5.6 months. There were no serious or adverse complications in any of the cases, and none of the measured parameters differed significantly between the groups.

CONCLUSION

Within the limitations of this study, ARP with DBBM-C and DPBM-C showed similar clinical, radiographic, and profilometric outcomes in nonintact extraction sockets.

Occlusive membranes for guided regeneration of inflamed tissue defects

Guided bone regeneration aided by the application of occlusive membranes is a promising therapy for diverse inflammatory periodontal diseases. Symbiosis, homeostasis between the host microbiome and cells, occurs in the oral environment under normal, but not pathologic, conditions. Here, we develop a symbiotically integrating occlusive membrane by mimicking the tooth enamel growth or multiple nucleation biomineralization processes. We perform human saliva and in vivo canine experiments to confirm that the symbiotically integrating occlusive membrane induces a symbiotic healing environment. Moreover, we show that the membrane exhibits tractability and enzymatic stability, maintaining the healing space during the entire guided bone regeneration therapy period. We apply the symbiotically integrating occlusive membrane to treat inflammatory-challenged cases in vivo, namely, the open and closed healing of canine premolars with severe periodontitis. We find that the membrane promotes symbiosis, prevents negative inflammatory responses, and improves cellular integration. Finally, we show that guided bone regeneration therapy with the symbiotically integrating occlusive membrane achieves fast healing of gingival soft tissue and alveolar bone.

Evaluation of alveolar ridge preservation in sockets with buccal dehiscence defects using two types of xenogeneic biomaterials: An in vivo experimental study

OBJECTIVES

Alveolar ridge preservation (ARP) has been extensively investigated in various preclinical and clinical studies, yielding favorable results. We aim to evaluate the effects of ARP using collagenated bovine bone mineral (CBBM) alone or particulated bovine bone mineral with a non-cross-linked collagen membrane (PBBM/NCLM) in tooth extraction sockets with buccal dehiscence in an experimental dog model.

MATERIALS AND METHODS

The mesial roots of three mandibular premolars (P2, P3, and P4) were extracted from six mongrel dogs 4 weeks after inducing dehiscence defects. ARP was randomly performed using two different protocols: 1) CBBM alone and 2) PBBM/NCLM. Three-dimensional (3D) volumetric, micro-computed tomography, and histological analyses were employed to determine changes over a span of 20 weeks.

RESULTS

In 3D volumetric and radiographic analyses, CBBM alone demonstrated similar effectiveness to PBBM/NCLM in ARP (p > .05). However, in the PBBM/NCLM group (3.05 ± 0.60 mm), the horizontal ridge width was well maintained 3 mm below the alveolar crest compared with the CBBM group (2.11 ± 1.01 mm, p = .002).

CONCLUSION

Although the radiographic changes in the quality and quantity of bone were not significant between the two groups, the use of PBBM/NCLM resulted in greater horizontal dimensions and more favorable maintenance of the ridge profile.

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.

Platelet-rich fibrin combined with a particulate bone substitute versus guided bone regeneration in the damaged extraction socket: An in vivo study

AIM

It has been proposed that platelet-rich fibrin (PRF) can be used to support bone regeneration during alveolar ridge augmentation. The aim of this study was to determine whether an approach utilizing PRF provides similar performance to the established guided bone regeneration (GBR) procedure.

MATERIALS AND METHODS

Two-wall defects were surgically created in beagle dogs and treated in three experimental groups: (i) a sticky bone (SB) substitute prepared using liquid PRF and deproteinized porcine bone mineral (DPBM); (ii) SB covered with solid PRF compressed into a membrane; and (iii) GBR performed using DPBM covered by a collagen membrane. Quantitative reverse-transcription polymerase chain reaction was applied to the specimen after 1 week of healing, and microcomputed tomography (micro-CT) and histological outcomes were analysed after 8 weeks of healing.

RESULTS

Compared with GBR, PRF resulted in a moderate increase in the expression levels of osteoblast and osteoclast markers, osteocalcin, and calcitonin receptor. Moreover, PRF modestly increased angiogenesis and the inflammation markers vascular endothelial growth factor (VEGF) and IL-6. Micro-CT and histological analyses confirmed the expected increased alveolar ridge area, with no significant differences between the three groups. Consistently, graft consolidation, as indicated by new bone formation at the defect site, did not differ significantly between groups.

CONCLUSIONS

The present results demonstrate that PRF-based approaches perform comparably to the established GBR procedure in terms of the consolidation of DPBM in two-wall alveolar defects.

Primary flap closure in alveolar ridge preservation for periodontally damaged extraction socket: A randomized clinical trial

INTRODUCTION

The effect of primary wound closure (PC) on alveolar ridge preservation (ARP) in periodontally damaged sockets has yet to be fully discovered.

METHODS

Periodontally damaged sockets were allocated to one of the following groups: (1) ARP with PC (group PC), and (2) ARP without PC (group secondary wound closure [SC]). Following tooth extraction and flap elevation, granule-type xenogeneic bone substitute material and a collagen barrier were applied. Ridge change was evaluated using cone-beam computed tomographic (CBCT) scans immediately after ARP and at 4 months. Core biopsy specimens were examined histomorphometrically.

RESULTS

A total of 28 patients were included in the analysis (13 in group PC, 15 in group SC). Histomorphometrically, the percentage of newly formed bone was 26.2 ± 17.7% and 24.6 ± 18.4% in groups PC and SC, respectively (independent t-test, degree of freedom [df] = 25, p > 0.05). Horizontal ridge changes on CBCT were -4.9 ± 3.1 mm and - 4.2 ± 2.5 mm in groups PC and SC at the 1 mm level below the ridge crest, respectively (independent t-test, df = 26, p > 0.05). Approximately half of the sites required additional bone augmentation at implant placement.

CONCLUSIONS

ARP with/without PC yielded similar new bone formation and radiographic ridge change. This clinical trial was not registered prior to participant recruitment and randomization (https://cris.nih.go.kr/cris/search/detailSearch.do/19718).

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.

Preclinical Evaluation of BMP-9-Treated Human Bone-like Substitutes for Alveolar Ridge Preservation following Tooth Extraction

The success of dental implant treatment after tooth extraction is generally maximized by preserving the alveolar ridge using cell-free biomaterials. However, these treatments can be associated with inflammatory reactions, leading to additional bone volume loss hampering dental implant positioning. Our group developed a self-assembled bone-like substitute constituted of osteogenically induced human adipose-derived stromal/stem cells (hASCs). We hypothesized that a bone morphogenetic protein (BMP) supplementation could improve the in vitro osteogenic potential of the bone-like substitute, which would subsequently translate into enhanced alveolar bone healing after tooth extraction. ASCs displayed a better osteogenic response to BMP-9 than to BMP-2 in monolayer cell culture, as shown by higher transcript levels of the osteogenic markers RUNX2, osterix (OSX/SP7), and alkaline phosphatase after three and six days of treatment. Interestingly, BMP-9 treatment significantly increased OSX transcripts and alkaline phosphatase activity, as well as pro-angiogenic angiopoietin-1 gene expression, in engineered bone-like substitutes after 21 days of culture. Alveolar bone healing was investigated after molar extraction in nude rats. Microcomputed tomography and histological evaluations revealed similar, or even superior, global alveolar bone preservation when defects were filled with BMP-9-treated bone-like substitutes for ten weeks compared to a clinical-grade biomaterial, with adequate gingival re-epithelialization in the absence of resorption.

Ridge preservation applying a novel hydrogel for early angiogenesis and osteogenesis evaluation: an experimental study in canine

Ridge preservation is universally acknowledged as the conventional method for the post-extraction healing yet there are no standard materials for the ideal healing outcome. Herein, a composite gel comprising gelatin nanoparticles (GNPs) and injectable platelet-rich-fibrin (i-PRF) as the potential candidate for extracted socket healing is introduced. The combination of GNPs and i-PRF not only possesses favorable mechanical properties to withstand external force but also accelerate the blood clotting time significantly. In addition, six beagle dogs were adopted to assess the angiogenic and osteogenic capacity of GNPs+i-PRF gel in vivo. The GNPs+i-PRF gel significantly produced the most blood vessels area, woven bone and low osteoclast activity in extracted sockets at 2 weeks postoperation and remarkably generated corticalization on the alveolar ridge crest at 8 weeks postoperation according to histological results. Therefore, GNPs+i-PRF gel can be recommended as the candidate grafting material regarding ridge preservation for its cost effectiveness, excellent biocompatibility, facilitation of blood clotting and favorable capacity of promoting angiogenesis and osteogenesis.

Comparing success of immediate versus delay loading of implants in fresh sockets: a systematic review and meta-analysis

BACKGROUND AND AIMS

The replacement of teeth with osseointegrated implants is one of the significant advances in the field of restorative dentistry. The time interval between tooth extraction and the implant can be very short or long. This systematic review and meta-analysis aimed to collect and evaluate articles related to determining the effect of instant loading of dental implants are placed in the fresh socket initial stability on the clinical success of the implant compared to delay loading dental implants.

MATERIALS AND METHODS

In this study, all the available articles indexed in leading databases, including PubMed, ISI Web of Science, Embase, PsycINFO, PROSPERO, and Scopus, were searched. The full text of the articles meeting the primary criteria to be included in this research was obtained and appraised. Data of studies were extracted if they were scored as a high or moderate level of evidence.

RESULTS

A total of 2258 published articles were found through electronic database searching. After screening the titles and abstracts, and full text of articles, 16 studies met the inclusion criteria and were included in the analysis. The results of this study revealed that regarding the success rate, although there was no significant difference between immediate and delayed of dental implants, immediate procedure showed a lower incidence of bone loss in single implants.

CONCLUSION

Based on the results of this study, immediate loading of dental implant, under certain conditions, is a successful treatment process and is effective in reducing treatment time. Thus, immediate loading represents a valid alternative to the traditional delayed loading rehabilitation.

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.

Combination of bone substitutes and vectors in periodontology and implantology: A systematic review

The aim of the systematic review was to analyze the use of combination of bone substitutes and vectors in periodontology and implantology among animals models and humans. Electronic databases were searched, and additional hand search was performed. The research strategy was achieved according to the PRISMA guidelines. The including criteria were: combination of bone substitutes and vectors, in vivo studies, a precise number of specimens, histological and radiographic analysis, written in English. The risk of bias was evaluated for individual studies. Thirty-two articles were selected and investigated in this systematic review. The results do not show a superiority of the use of composite biomaterial in comparison with simple biomaterial but suggest the efficacity of their utilization as a carrier of bioactive agents. Future studies need to identify the suitable association of bone substitutes and vectors and explore interest in their use such as the support of growth factors.

Efficacy of Flat-Top Hand-Piece Using 980 nm Diode Laser Photobiomodulation on Socket Healing after Extraction: Split-Mouth Experimental Model in Dogs

The objective was to evaluate the effect of photobiomodulation (PBM) using 980 nm diode laser therapy (0.60 W, 0.77 W cm^-2 , 36 J, 46 J cm^-2 , 60 s) irradiated in continuous wave mode by flat-top hand-piece on socket healing in the maxilla and mandible. A split-mouth experimental design was performed on 6 dogs. The 3^rd premolar tooth was extracted from the maxilla and mandibles for both sides. The right-sided sockets were irradiated (PBM group), and the left-sided sockets were kept as control. Irradiation was done after extraction and at 48-h interval for 14 days. Both the buccal and lingual sides were irradiated to reach a total irradiation time of 120 s. Bone density was evaluated at 3, 4 and 5 weeks using cone beam computed tomography. We showed that maxillary sockets in the PBM group had higher bone density compared to control one at 3, 4, 5 weeks (P = 0.029, <0.001, <0.001), respectively. Mandibular sockets revealed no significant difference between PBM and control at 3 weeks (P = 0.347), while at 4 and 5 weeks PBM group showed higher bone density (P = 0.004, <0.001). In both groups, there was a significant increase (P < 0.001) in bone density by time which was higher in the PBM group. We concluded that PBM using a flat-top hand-piece of 980-nm improved the bone density of extraction sockets.

Evaluation of the mechanical properties and clinical efficacy of biphasic calcium phosphate-added collagen membrane in ridge preservation

PURPOSE

This study aimed to evaluate the biocompatibility and the mechanical properties of ultraviolet (UV) cross-linked and biphasic calcium phosphate (BCP)-added collagen membranes and to compare the clinical results of ridge preservation to those obtained using chemically cross-linked collagen membranes.

METHODS

The study comprised an in vitro test and a clinical trial for membrane evaluation. BCP-added collagen membranes with UV cross-linking were prepared. In the in vitro test, scanning electron microscopy, a collagenase assay, and a tensile strength test were performed. The clinical trial involved 14 patients undergoing a ridge preservation procedure. All participants were randomly divided into the test group, which received UV cross-linked membranes (n=7), and the control group, which received chemically cross-linked membranes (n=7). BCP bone substitutes were used for both the test group and the control group. Cone-beam computed tomography (CBCT) scans were performed and alginate impressions were taken 1 week and 3 months after surgery. The casts were scanned via an optical scanner to measure the volumetric changes. The results were analyzed using the nonparametric Mann-Whitney U test.

RESULTS

The fastest degradation rate was found in the collagen membranes without the addition of BCP. The highest enzyme resistance and the highest tensile strength were found when the collagen-to-BCP ratio was 1:1. There was no significant difference in dimensional changes in the 3-dimensional modeling or CBCT scans between the test and control groups in the clinical trial (P>0.05).

CONCLUSIONS

The addition of BCP and UV cross-linking improved the biocompatibility and the mechanical strength of the membranes. Within the limits of the clinical trial, the sites grafted using BCP in combination with UV cross-linked and BCP-added collagen membranes (test group) did not show any statistically significant difference in terms of dimensional change compared with the control group.

Immediate versus delayed application of bone morphogenetic protein-2 solution in damaged extraction sockets: a preclinical in vivo investigation

OBJECTIVE

To compare the clinical, radiographic, and histological healing patterns between the immediate and delayed applications of bone morphogenetic protein-2 (BMP-2) in damaged extraction sockets in dogs.

MATERIALS AND METHODS

The distal roots of the fourth premolars of the mandible were extracted bilaterally in five beagle dogs, and buccal bone defects (4 mm wide and 9 mm high) were surgically created. Collagenated biphasic calcium phosphate (CBCP) soaked for 10 min in 100 μL of BMP-2 solution was applied immediately to the defect site in the control group. In the test group, the BMP-2 solution of same dose was injected into the grafted site 2 weeks after grafting with a saline-soaked CBCP. The dogs were sacrificed 2 weeks later. Clinical, histological, and radiographic analyses were followed.

RESULTS

Swelling and inflammatory reactions were predominantly observed in the control group at 2 weeks. The area of new bone formation was significantly larger in the control group compared with the test group (10.8 ± 7.0 mm² [mean ± SD] and 6.3 ± 3.1 mm², respectively; p = 0.043). No significant difference was found in ridge width at 2 mm, 4 mm and 6 mm below the lingual bone crest between the control (2.6 ± 1.0 mm, 3.2 ± 0.9 mm and 4.5 ± 0.5 mm, respectively) and test group (3.3 ± 1.0 mm, 3.7 ± 1.3 mm and 4.2 ± 1.0 mm; all p > 0.05).

CONCLUSIONS

Delayed application of BMP-2 2 weeks after surgery did not show any advantage over immediate application of BMP-2 in terms of new bone formation.

CLINICAL RELEVANCE

This study suggests that it might be better to apply BMP-2 immediately in alveolar ridge preservation, instead of delayed application, in order to enhance new bone formation.

Ridge Augmentation Using β-Tricalcium Phosphate and Biphasic Calcium Phosphate Sphere with Collagen Membrane in Chronic Pathologic Extraction Sockets with Dehiscence Defect: A Pilot Study in Beagle Dogs

This study was conducted to comparatively examine spontaneous healing versus ridge augmentation, in surgically-created dehiscence defects, associated with chronic pathology in dogs. Mandibular second, third and fourth premolars (P2, P3 and P4) were hemi-sectioned, and a dehiscence defect was created at the mesial root, while a groove was made on the buccal area from the top of the teeth to the bottom of the defect, exposing the dental pulp. The mesial roots of P2, P3 and P4 were extracted 1 month after the induction of the dehiscence defect with chronic pathology. Three teeth were randomly allocated to these experimental groups: (i) spontaneous healing without any bone graft (Control group: C); (ii) ridge augmentation with β-tricalcium phosphate (β-TCP) granules (Test 1 group: T1); and (iii) ridge augmentation with 60% hydroxyapatite (HA) and 40% β-TCP microspheres (Test 2 group: T2). Postmortem histopathologic examination showed significant between-group differences in C and T1 and C and T2 in bone volume/tissue volume in qualitative micro-computed tomography (CT) analysis, as well as significant intergroup differences in the coronal area at 4 and 12 weeks. The composition of connective tissue and mineralized bone in C and T1 were higher than in T2 at 4 weeks of healing, whereas the composition of mineralized bone was higher in T2 than in T1 at 12 weeks of healing. Biphasic calcium phosphate, composed of 60% HA and 40% β-TCP microsphere (i) potentially prevented marked osteoclastic resorption and (ii) promoted ridge preservation in the extraction socket with the dehiscence defect and chronic pathology.

Ridge reconstruction in damaged extraction sockets using tunnel β-tricalcium phosphate blocks: A 6-month histological study in beagle dogs

OBJECTIVE

The present study aimed to evaluate the histological outcome of tunnel β-TCP blocks grafting in extraction sockets missing the buccal bone wall, after 6 months of healing.

BACKGROUND

Tunnel β-tricalcium phosphate (β-TCP) blocks made of randomly organized tunnel-shaped β-TCP ceramics appeared promising for alveolar ridge preservation in tooth extraction sockets missing the buccal bone, in a previous study in dogs, with a 2-month healing time.

METHODS

In six beagle dogs, the maxillary first premolars were extracted and the buccal bone was surgically removed to create bone defects of 4 mm (mesio-distal) × 5 mm (apico-coronal) × 4 mm (bucco-palatal). Thus, extraction sockets missing the buccal bone plate were grated with tunnel β-TCP blocks (test) or left empty for spontaneous healing (control). Histology/histomorphometry was performed after 6 months of healing.

RESULTS

The horizontal bucco-palatal width of the alveolar ridge was significantly greater at test sites than at control sites. The amount of mineralized tissue was greater at test sites (57.8% ± 11.1%) than at control sites (28.9% ± 8.5%), while the amount of connective tissue was significantly greater at control sites (41.7% ± 6.4%) than at test sites (19.6% ± 9.2%). No significant difference was found between sites in terms of basic multicellular units and bone marrow. Residual β-TCP at test sites was 5.8% ± 3.2%.

CONCLUSION

Grafting with tunnel β-TCP block significantly limited the resorption of the alveolar ridge at extraction sockets missing the buccal bone compared with sites left to heal spontaneously, even after 6-month follow-up.

Comparative assessment of anterior maxillary alveolar ridge preservation with and without adjunctive use of enamel matrix derivative: A randomized clinical trial

OBJECTIVES

The aim of this randomized, controlled, parallel-arm study was to evaluate the (a) radiographic bone dimensional changes, (b) postoperative discomfort, and (c) early soft tissue wound healing outcomes, following extraction of maxillary anterior teeth (central and lateral incisors) and treatment with alveolar ridge preservation (ARP) with and without the adjunctive use of enamel matrix derivative (EMD).

METHODS

Thirty extraction sockets were randomly assigned to two groups: deproteinized bovine bone mineral with 10% collagen covered with collagen membrane with the adjunctive use of EMD (test group) and without EMD (control group). Bone dimensional changes were measured using cone beam computed tomography at 3 and 5 months after ARP. The severity and duration of pain and swelling were evaluated using self-reported questionnaires, and soft tissue wound healing outcomes were assessed clinically. Chi-square tests and t tests were conducted to compare differences between the two groups.

RESULTS

Radiographic and clinical analyses showed no significant differences in horizontal and vertical bone dimensional changes and soft tissue wound healing outcomes (including spontaneous bleeding, persistent swelling, and ulceration) between the two groups. There were no significant differences in the severity of pain and swelling between the two groups, but the durations of pain (difference [df] = 1.20, 95% CI = 0.33-2.06; p = .008) and swelling (df = 1.06, 95% CI = 0.11-2.01; p = .029) were significantly reduced in the test group.

CONCLUSION

Alveolar ridge preservation with the adjunctive use of EMD reduced the durations of postoperative pain and swelling following maxillary anterior teeth extraction.

The influence of deproteinised bovine bone mineral on dimensional changes in the maxillary second incisor socket

OBJECTIVES

To investigate the dimensional changes following the extraction of maxillary second incisors and to evaluate the influence of deproteinised bovine bone mineral on the healing outcomes.

MATERIALS AND METHODS

The second maxillary incisors in nine dogs were extracted bilaterally in a minimally traumatic manner. Deproteinised bovine bone mineral with collagen (DBBMC) and a collagen matrix (CM) was placed in one socket with the contralateral socket left to heal naturally. After 3 months of healing, the dogs were sacrificed and the pre-maxilla resected. Cone beam computerised tomography scans (CBCTs) were obtained and the specimens prepared for histological preparation and analysis. Surface scans of study models taken pre- and post-extraction were digitally subtracted to analyse volumetric changes.

RESULTS

All dogs healed uneventfully without any complications. No inflammation was seen, and DBBMC was well integrated into a network of mineralised tissues, bone marrow and connective tissue. The horizontal width of the buccal crest was found to be significantly greater in grafted sockets, but the vertical height to be similar. No significant difference was seen in regard to volumetric changes in sockets over 3 months post-extraction.

CONCLUSION

Maxillary second incisor sockets of dogs grafted with DBBMC post-extraction had significantly greater horizontal width at the ridge crest compared with ungrafted sockets. Volumetric analysis revealed no significant difference between grafted and non-grafted sockets, suggesting possible soft tissue thickening post-extraction to counteract osseous resorption.

Periodontal regenerative therapy in endo-periodontal lesions: a retrospective study over 5 years

Purpose

The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions.

Methods

A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up.

Results

At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction (4.52±1.06 mm) than the DBBM + collagen membrane group (4.04±0.82 mm). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group (5.15±1.54 mm) was comparable to that of the DBBM + collagen membrane group (5.35±1.84 mm). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%.

Conclusions

This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

Recombinant human BMP9 (RhBMP9) in comparison with rhBMP2 for ridge augmentation following tooth extraction: An experimental study in the Beagle dog

OBJECTIVES

The purpose of this study was to compare the effects of rhBMP2 with rhBMP9 on ridge augmentation following healing of extraction sockets in dogs.

MATERIAL AND METHODS

Five male Beagle dogs, approximately 12 months of age, were used. The mesial roots of the four maxillary premolars were endodontically treated. The distal roots were extracted, and the buccal bony walls removed. All extraction sockets were filled with deproteinized bovine bone mineral (DBBM). A collagen membrane was soaked with 4 μg or 20 μg of rhBMP9, 20 μg of rhBMP2 or sterile saline and placed over the augmented sites. All animals were euthanized after 8 weeks of healing and investigated by micro-CT and histologic analysis. A one-way ANOVA with Tukey's HSD post hoc test was used to compare the differences between the four groups.

RESULTS

New bone apposition in all defects was observed from the original bone. RhBMP samples showed an increase in bone formation in the buccal area and better integration of DBBM particles when compared to control sites. Both rhBMP9 defects showed higher values of bone (p = 0.024), bone marrow (p = 0.044), and total augmentation volume (p = 0.033) than the rhBMP2 (20 μg) or control sites. Highest bone area was found in rhBMP9 defects (p = 0.895).

CONCLUSIONS

Within the limitations of the present study, rhBMP9 sites demonstrated higher bone-inducing potential in combination with DBBM than rhBMP2. While rhBMP9s failed to demonstrate a clear dose-response relationship to the outcomes, future studies are necessary to evaluate the appropriate dose and carrier systems.

Volumetric, Radiographic, and Histologic Analyses of Demineralized Dentin Matrix Combined with Recombinant Human Bone Morphogenetic Protein-2 for Ridge Preservation: A Prospective Randomized Controlled Trial in Comparison with Xenograft

The aim of this study was to evaluate the clinical, volumetric, radiographic, and histologic aspects of autogenous demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) used for ridge preservation, compared to those of deproteinized bovine bone with collagen (DBBC). Following atraumatic extraction, the socket was filled with DBBC, DDM, or rhBMP-2/DDM. Scanned images of dental casts and cone beam computed tomographs (CBCT) were superimposed for the calculation of soft and hard tissue volume alteration. Preoperative and postoperative measurements of the height and width of the alveolar ridge were compared using CBCT images. After 4 months, bone specimens were harvested for histomorphometric assessment. Loss of hard and soft tissue volume occurred at 4 months after extraction and ridge preservation in all groups. No volumetric differences were detected among the three groups before and 4 months after ridge preservation. The reduction in the horizontal width at 5 mm was higher in the DBBC compared to the DDM. Histologically, approximately 40% newly formed bone was founded in rhBMP-2/DDM group. The autogenous dentin matrix used to fill the socket was as beneficial for ridge preservation as conventional xenografts. The combination of rhBMP-2 with dentin matrix also demonstrated appreciable volumetric stability and higher new bone formation compared to DDM alone and DBBC.

Alveolar ridge regeneration of damaged extraction sockets using deproteinized porcine versus bovine bone minerals: A randomized clinical trial

Backgrounds

Clinical benefits in bone grafting of intact extraction socket have been widely known, but limited evidence is available for the procedure in damaged extraction sockets due to periodontal disease.

Purpose

This study aimed to determine the dimensional alteration of alveolar ridge following bone grafting of damaged extraction sockets, and compare the outcomes of using deproteinized bovine (DBBM) versus porcine bone mineral (DPBM) in the damaged sockets.

Materials and Methods

One hundred patients (n = 50 for each group) with periodontitis‐induced damaged extraction socket were included in this randomized, single‐blind trial. After removal of tooth and granulation tissue, sites were grafted with either DBBM (DBBM group) or DPBM (DPBM group), and covered with collagen membrane. Linear/volumetric analyses of hard and soft‐tissue dimensions were performed on reconstructed/superimposed computed tomography and scanned cast images, taken immediately and 4 months after surgery.

Results

The two groups showed comparable hard tissue augmentation with minimal reductions in the grafted volume, as well as in vertical (1.22 ± 2.16 and 1.45 ± 1.92 mm for DPBM and DBBM group, respectively) and horizontal (1.43 ± 3.40 and 1.83 ± 2.85 mm on the central section, respectively) dimensions at 4 months after surgery. However, several cases showed large variations in maintenance of the grafted volume. None of the measured parameters in hard and soft tissue dimensions differed significantly between DBBM and DPBM sites.

Conclusions

DBBM and DPBM can comparably augment damaged extraction sockets with minimal postoperative reduction of the grafted volume. However, the large variations in the results should be further evaluated for application in routine dental clinics.

Effect of Hypoxia-Inducible Factor 1α on Early Healing in Extraction Sockets

The aim of the present study was to investigate the effect of hypoxia-inducible factor 1α (HIF1A) on the early healing (4 weeks) of extraction sockets exhibiting partial loss of the labial bone. Two extraction sockets of the maxillary incisors from each of six dogs were assigned to two treatment modalities: deproteinized bovine bone mineral (i) with 10% collagen (DBBM-C) soaked with HIF1A and covered by a collagen membrane (CM) (HIF group) or (ii) treated with DBBM-C only and covered by a CM (control group). Microcomputed tomography revealed some degree of collapse of the labial contour. The totally augmented volume and new bone volume did not differ significantly between two groups (P > 0.05). The histological analysis revealed that the apical area of the socket was mostly filled with newly formed bone, while there was less newly formed bone in the coronal area and incomplete cortex formation. The histomorphometric analysis revealed that the area of newly formed bone was significantly larger in the HIF group than the control group (12.16 ± 3.04 versus 9.48 ± 2.01 mm², P < 0.05), while there was no significant intergroup difference in the total augmented area. In conclusion, even though DBBM-C soaked with HIF1A enhanced histomorphometric bone formation, this intervention did not demonstrate superiority in preventing ridge shrinkage compared to DBBM-C alone. Clinical relevance of these findings should be further studied.

Three-dimensional analysis of bone remodeling following ridge augmentation of compromised extraction sockets in periodontitis patients: A randomized controlled study

OBJECTIVES

The aim of this study was to analyze linear and volumetric hard tissue changes in severely resorbed alveolar sockets after ridge augmentation procedure and to compare them with spontaneous healing using three-dimensional cone beam computed tomography (CBCT).

MATERIAL AND METHODS

Thirty patients (mean age 53.2 ± 6.3 years) requiring tooth extraction for advanced periodontitis were randomly allocated to test and control groups. The test sites were grafted using a collagenated bovine-derived bone (DBBM-C) covered with a collagen membrane, while control sites had spontaneous healing. Both groups healed by secondary intention. Linear and volumetric measurements were taken on superimposed CBCT images obtained after tooth extraction and 12 months later.

RESULTS

Greater horizontal shrinkage, localized mainly in the crestal zone, was observed in the control group (4.92 ± 2.45 mm) compared to the test group (2.60 ± 1.24 mm). While both groups presented a rebuilding of the buccal wall, it was most pronounced in the grafted sockets (2.50 ± 2.12 mm vs. 0.51 ± 1.02 mm). A significant difference was also registered in the percentage of volume loss between grafted and non-grafted sites (9.14% vs. 35.16%, p-value <.0001).

CONCLUSION

Alveolar sockets with extensive buccal bone deficiencies undergo significant three-dimensional volumetric alterations following natural healing. The immediate application of a slow-resorbing xenograft with a covering collagen membrane seems to be effective in improving alveolar ridge shape and dimensions, thus potentially reducing the need for adjunctive regenerative procedures at the time of implant placement.

A Novel Procedure for the Immediate Reconstruction of Severely Resorbed Alveolar Sockets for Advanced Periodontal Disease

Background. Several clinical techniques and a variety of biomaterials have been introduced over the years in an effort to overcome bone remodeling and resorption after tooth extraction. However, the predictability of these procedures in sockets with severely resorbed buccal/lingual plate due to periodontal disease is still unknown. Case Description. A patient with advanced periodontitis underwent extraction of upper right lateral and central incisors. The central incisor exhibited complete buccal bone plate loss and a 9 mm vertical bone deficiency on its palatal side. The alveolar sockets were filled with collagen sponge and covered with a nonresorbable high-density PTFE membrane. Primary closure was not attained and any rigid scaffold material was not used. Histologic analysis provided evidence of new bone formation. At 12 months a cone-beam computed tomographic scan revealed enough bone volume to insert two conventional dental implants in conjunction with minor horizontal bone augmentation procedures. Clinical Implications. This case report would seem to support the potential of the proposed reconstructive approach in changing the morphology of severely resorbed alveolar sockets, minimizing the need for advanced bone regeneration procedures during implant placement.

Localized bone regeneration around dental implants using recombinant bone morphogenetic protein-2 and platelet-derived growth factor-BB in the canine

OBJECTIVES

To test whether or not one of two biological mediators (recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor (rhPDGF-BB)) is superior to the other and compared with control groups for bone regeneration around implants based on histomorphometrical outcome measures.

MATERIALS AND METHODS

Box-type defects (10 × 5 × 5 mm) were prepared on the buccal sides of the left and right edentulous ridge in ten mongrel dogs. Implants were placed at each site, the defects either received (i) bovine-derived particulated bone mineral (DBBM) mixed with rhBMP-2 and a collagen membrane (CM) (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB and CM (DBBM/PDGF), (iii) DBBM and CM (DBBM) and (iv) empty control (control). Animals were euthanized post-surgery at 8 weeks and 16 weeks. Histomorphometrical analyses were performed.

RESULTS

The mean percentages of regenerated area within total defect area amounted to 56.95% for DBBM/BMP-2, 48.86% for DBBM/PDFG, 33.44% for DBBM and 1.59% for control at 8 weeks, and 26.79% for DBBM/BMP-2, 23.78% for DBBM/PDFG, 30.21% for DBBM and 5.07% for control at 16 weeks with no statistically significant differences between the groups (P > 0.05). The mean amount of regenerated bone was 26.97% for DBBM/BMP-2, 22.02% for DBBM/PDFG, 5.03% for DBBM and 1.25% for control at 8 weeks, and at 16 weeks, these values were lower in the two groups with biological mediators (DBBM/BMP-2 = 13.35%; DBBM/PDGF = 6.96%) and only slightly increased in group DBBM (10.68%) and the control group (4.95%) compared with 8 weeks. The first bone-to-implant contact values on the buccal side were minimal for DBBM/BMP-2 (0.57 mm) and maximal for control (3.72 mm) at 8 weeks.

CONCLUSIONS

The use of biological mediators (rhBMP-2 and rhPDGF-BB) can increase the amount of bone regeneration at dehiscence-type defects compared with controls at 8 weeks, but not at 16 weeks due to enhanced hard tissue remodeling processes.

The use of leucocyte and platelet-rich fibrin in socket management and ridge preservation: a split-mouth, randomized, controlled clinical trial

AIM

To investigate the influence of the use L-PRF as a socket filling material and its ridge preservation properties.

MATERIALS AND METHODS

Twenty-two patients in need of single bilateral and closely symmetrical tooth extractions in the maxilla or mandible were included in a split-mouth RCT. Treatments were randomly assigned (L-PRF socket filling versus natural healing). CBCT scans were obtained after tooth extraction and three months. Scans were evaluated by superimposition using the original DICOM data. Mean ridge width differences between timepoints were measured at three levels below the crest on both the buccal and lingual sides (crest -1 mm (primary outcome variable), -3 mm and -5 mm).

RESULTS

Mean vertical height changes at the buccal were -1.5 mm (±1.3) for control sites and 0.5 mm (±2.3) for test sites (p < 0.005). At the buccal side, control sites values were, respectively, -2.1 (±2.5), -0.3 mm (±0.3) (p < 0.005) and -0.1 mm (±0.0), and test sites values were, respectively, -0.6 mm (±2.2) (p < 0.005), -0.1 mm (±0.3) and 0.0 mm (±0.1). Significant differences (p < 0.005) were found for total width reduction between test (-22.84%) and control sites (-51.92%) at 1 mm below crest level. Significant differences were found for socket fill (visible mineralized bone) between test (94.7%) and control sites (63.3%).

CONCLUSION

The use of L-PRF as a socket filling material to achieve preservation of horizontal and vertical ridge dimension at three  months after tooth extraction is beneficial.

Ridge preservation of extraction sockets with chronic pathology using Bio-Oss® Collagen with or without collagen membrane: an experimental study in dogs

OBJECTIVES

This study aimed to evaluate the dynamics of newly bone formation and dimensional change in diseased extraction sockets using Bio-Oss^® Collagen with or without a collagen membrane.

MATERIAL AND METHODS

In six beagle dogs, right and left 3rd and 4th mandibular premolars were hemisected and the distal roots were removed. Combined endodontic-periodontic lesions were induced in all sites using black silk, collagen sponge, endodontic files, and application of Porphyromonas gingivalis. After 4 months, among 4 premolars, three teeth were randomly selected per dog and allocated to the following experimental groups: Control group (no treatment but debridement), Test 1 group (only Bio-Oss^® Collagen graft), and Test 2 group (Bio-Oss^® Collagen graft with a collagen membrane). After 7 months from the baseline, the beagle dogs were sacrificed for histomorphometric and Micro-CT analysis.

RESULTS

The vertical distance between buccal and lingual crests in the Control group (2.22 ± 0.26 mm) and Test 2 group (1.80 ± 0.16 mm) was significantly different. The socket of the Test 2 group (27.04 ± 5.25%) was occupied by a greater quantity of bone graft compared to the Test 1 group (18.49 ± 2.11%).

CONCLUSION

Ridge preservation in diseased extraction sockets could compensate for buccal bone resorption by contact osteogenesis surrounding the bone graft particles at the bucco-coronal area during socket healing, and the application of a collagen membrane at the entrance of the socket is useful for preserving graft material at the coronal part of the socket.