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

Alveolar Ridge Preservation Using a Collagenated Xenograft: A Randomized Clinical Trial

OBJECTIVES

This study sought to evaluate the efficacy of cancellous bovine bone mineral granules and 10% porcine collagen (deproteinized bovine bone mineral with collagen [DBBM-C]; (OCS-B Collagen® [Straumann XenoFlex], NIBEC, Korea) in a mouldable block form, with or without socket seal, using autogenous free gingival graft (FGG).

METHODS

Fifty-four patients were included and randomly assigned to one of three groups: (1) spontaneous healing (control group), (2) alveolar ridge preservation (ARP) using DBBM-C (DBBM-C group), and (3) ARP employing DBBM-C sealed with FGG (DBBM-C/FGG group). Bone biopsy and implant fixture placement were performed 180 days after ARP. Cone-beam computed tomography, histological analysis, implant stability, and three-dimensional volumetric analysis were conducted.

RESULTS

Of the 54 patients, 4 dropped out owing to loss of follow-up and osseointegration failure. The changes in alveolar bone during follow-up were not significantly different. Between 84- and 180-day postextraction, the volume of the DBBM-C and DBBM-C/FGG groups was maintained at 3 mm below the alveolar ridge crest (0.72 ± 0.80 mm, 6.05 ± 6.69%), whereas the volume in the control group decreased (-0.37 ± 1.31 mm, -2.10% ± 8.37%) (P = .026). The DBBM-C/FGG group exhibited less horizontal ridge resorption at 1 mm below the alveolar crest (-9.19 ± 5.09 mm, -73.67% ± 32.53%) between preextraction and 84 days postextraction (P = .049). In all groups, the implant stability quotient remained above 70.

CONCLUSIONS

Within the limitations of this study, both ARP using DBBM-C with and without socket sealing effectively preserved the width dimension of the alveolar ridge, with no significant difference in alveolar bone resorption. However, socket sealing appeared to enhance the stability of the bone graft and bone quality.

CLINICAL RELEVANCE

The use of DBBM-C for ARP seems to aid in volume maintenance as compared with spontaneous healing. Gingival sealing with an FGG can help maintain the width of the alveolar ridge. This clinical trial was not registered prior to participant recruitment and randomization. This study was registered at WHO ICTRP (https://trialsearch.who.int/Trial2.aspx?TrialID=KCT0008266).

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.

Advances in biomaterials for oral-maxillofacial bone regeneration: spotlight on periodontal and alveolar bone strategies

The intricate nature of oral-maxillofacial structure and function, coupled with the dynamic oral bacterial environment, presents formidable obstacles in addressing the repair and regeneration of oral-maxillofacial bone defects. Numerous characteristics should be noticed in oral-maxillofacial bone repair, such as irregular morphology of bone defects, homeostasis between hosts and microorganisms in the oral cavity and complex periodontal structures that facilitate epithelial ingrowth. Therefore, oral-maxillofacial bone repair necessitates restoration materials that adhere to stringent and specific demands. This review starts with exploring these particular requirements by introducing the particular characteristics of oral-maxillofacial bones and then summarizes the classifications of current bone repair materials in respect of composition and structure. Additionally, we discuss the modifications in current bone repair materials including improving mechanical properties, optimizing surface topography and pore structure and adding bioactive components such as elements, compounds, cells and their derivatives. Ultimately, we organize a range of potential optimization strategies and future perspectives for enhancing oral-maxillofacial bone repair materials, including physical environment manipulation, oral microbial homeostasis modulation, osteo-immune regulation, smart stimuli-responsive strategies and multifaceted approach for poly-pathic treatment, in the hope of providing some insights for researchers in this field. In summary, this review analyzes the complex demands of oral-maxillofacial bone repair, especially for periodontal and alveolar bone, concludes multifaceted strategies for corresponding biomaterials and aims to inspire future research in the pursuit of more effective treatment outcomes.

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.

Potentials of pure xenograft materials in maxillary ridge augmentation: A case series

Many patients require edentulous ridge augmentation for dental implant placement. The main objective of this study was to evaluate the results of maxillary edentulous ridge augmentation exclusively with xenograft materials with and without simultaneous sinus floor elevation. This study reports the data retrieved from the records of 16 patients. The treatment outcome was assessed at least 6 months, postoperatively. Paired samples t-test or Wilcoxon Signed Rank test was used to compare the pre-and postoperative ridge dimensions. Dental implants were placed simultaneously in 7 patients, while 9 patients underwent delayed implant placement. In total, 68 implants were placed, and 12 patients also underwent maxillary sinus floor augmentation. A significant bone gain was achieved in both horizontal and vertical dimensions of edentulous maxillary ridges (P < 0.001). Ridge width increased by an average of 4.35 ± 1.90 mm (95% CI: 3.84 to 4.85 mm) while ridge height in areas of sinus floor augmentation increased by 8.19 ± 2.91 mm (95% CI: 7.33 to 9.05 mm). Within the study limitations, it appears that maxillary ridge augmentation according to the guided bone regeneration (GBR) protocols with exclusive use of xenograft particulate materials can provide optimal bone quantity for dental implant placement.

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.

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.

A three-in-one alveolar process reconstruction protocol for maxillary molar sites with severe residual bone height deficiency: A proof-of-concept pilot study

BACKGROUND

Implant placement in maxillary molar sites with severe height deficiency often requires multiple surgeries, which was time-consuming, invasive, and subject to serious postoperative complications.

PURPOSE

To introduce and assess a three-in-one technique (extraction, alveolar ridge preservation [ARP], and sinus elevation) for augmenting deficiency maxillary molar alveolar ridges.

MATERIAL AND METHODS

Fourteen patients with severe posterior maxillary ridge height deficiency underwent extraction, sinus elevation via an intrasocket window and ARP using sticky bone and then covered with acellular dermal matrix (ADM). Primary closure was intentionally not obtained. Cone-beam computed tomography and periapical radiography were used to measure dimensional ridge changes over time. Bone biopsies were taken at implant placement 7-21 months after surgery, which proceeded without additional grafting. Peri-implant soft tissue was assessed after 8-12 months of functional loading.

RESULTS

Maxillary molar sites (13 first molars, 1 second molar) with a mean sinus floor height of 1.73 ± 0.86 mm and mean buccal plate thickness of 1.62 ± 1.15 mm were elevated and grafted. Immediately after surgery, the mean sinus floor height was 14.03 ± 1.97 mm and the alveolar thickness at virtual implant platform level was 12.99 ± 1.88 mm. After 5-9 months healing, those measurements decreased by 2.45 ± 1.73 mm (p = 0.000) and 3.88 ± 3.95 mm (p = 0.006), respectively. Healed ridges were composed of 18.74% ± 4.34% mean vital bone and 19.08% ± 9.10% mean residual graft. After 8-12 months of functional loading, the peri-implant tissue appeared healthy, and there was a mean marginal bone loss of 0.12 ± 0.11 mm.

CONCLUSIONS

For maxillary first molar sites with severe sinus floor height deficiency, this minimally invasive three-in-one treatment allows for uncomplicated implant placement and short-term functional stability.