The Processing of Xenografts Will Result in Different Clinical Responses

Three Factors for Long-Term Dental Implant Success: Up to 40-year Follow-up

This article provides clinicians with 3 main factors that relate to long-term success. Long term in this article represents the lifespan of the patient, often requiring more than 40 years of function on the implant restoration. Literature is reviewed and used to provide evidence for these recommendations. Cases are presented to demonstrate these critical factors.

Comparative Effectiveness of an Autologous Dentin Matrix for Alveolar Ridge Preservation

An urgent issue is the preservation or reconstruction of the volume of bone tissue in planning and surgical treatment in the fields of medicine, such as traumatology, orthopedics, maxillofacial surgery and dentistry. After tooth extraction, resorption of the bone tissue of the alveolar crest of the jaws occurs, which must either be further eliminated by performing additional operations or using osteoplastic material for socket preservation at the extraction stage. Background and Objectives: The aim of the study was a comparative analysis of various osteoplastic materials used to preserve the volume of bone tissue in the preimplantation period. Materials and Methods: As part of the study, 80 patients were treated, who underwent socket preservation using xenografts, plasma enriched with growth factors, an autologous dentin matrix (ADM) and hydroxyapatite. Results: The results of the treatment 16 weeks after removal were comprehensively analyzed using a morphometric analysis of the bone's volume, cone beam tomography and morphological examination of burr biopsy specimens, as well as by determining the stability of the installed implant at different stages of treatment. Conclusions: The lowest level of bone tissue resorption according to the CBCT data was noted in the ADM and xenograft groups. It should be noted that the use of osteoplastic material in jaw surgery when reconstructing alveolar defects is an essential procedure for preventing the atrophy of bone tissue.

Comparison of the healing process of xenografts with three different sources in critical-size bone defects: An in vivo study

Background

Xenograft bone substitutes can be obtained from different animals and processed using various methods. The present in vivo study evaluated bone regeneration after using three types of xenografts with different sources in critical-sized bone defects in rabbit calvaria.

Methods

Four 8-mm defects were created in calvaria of 14 New Zealand and white male rabbits. Three out of four defects were filled with xenografts of bovine, camel, and ostrich sources. The fourth defect was left unfilled as the control group. Seven rabbits were sacrificed after eight weeks and seven others after 12 weeks. Micro-CT imaging and histologic evaluation were further performed on dissected calvarias.

Results

After 8 and 12 weeks, the highest and lowest percentages of new bone formation were observed in the camel (27.71% and 41.92%) and control (11.33% and 15.96%) groups, respectively. In the case of residual material, the ostrich group had the most value after eight weeks (53%), while after 12 weeks, it was highest in the camel group (37%). Micro-CT findings were consistent with histologic results.

Conclusion

Although all three xenografts can be good choices for treating bone defects, camel-sourced xenograft seemed to be better than the other two groups. The origin and processing procedures of xenografts affected their final characteristics, which should be considered for clinical use.

Success of Xenografts in Alveolar Ridge Preservation Based on Histomorphometric Outcomes

Different xenograft approaches in alveolar ridge preservation (ARP) are essential to understand relative to their histomorphometric outcomes. Therefore, the aim of this study involved studying biomaterials of a xenograft nature that are used in ARP procedures, to compare the different approaches and evaluate their efficacy in relation to histomorphometric data. An electronic search was completed using the databases: Ovid (Medline), Google Scholar and Wiley Online Library, including a hand search for relevant articles and grey literature. Only randomised controlled trials, using xenograft biomaterials for alveolar ridge preservation procedures involving human studies, dated from 2010-2022 were included in the review. An initial search yielded 4918 articles, after application of the eligibility criteria, 18 studies were deemed eligible for inclusion in the systematic review. The two main xenograft groups found were of bovine origin and of porcine origin. The main histomorphometric outcomes evaluated included new bone percentage (N.B%) and residual graft percentage (R.G%). The mean N.B% for the bovine and porcine groups were 33.46% and 39.63% respectively and the mean R.G% for the bovine and porcine groups were 19.40% and 18.63% respectively. The current evidence suggests that the two main xenograft biomaterials used in ARP procedures after tooth extraction, which are of bovine and porcine origin, displayed effectiveness in producing new bone.

Clinical application of platelet-rich fibrin to enhance dental implant stability: A systematic review and meta-analysis

Objective

To investigate the effect of platelet-rich fibrin application on implant stability.

Study design

Five databases, namely, PubMed, Embase, Web of Science, Wiley, and China National Knowledge Infrastructure, were searched for reports published up to November 20, 2022. Randomized controlled trials (RCT), including parallel RCTs and split-mouth RCTs, with at least 10 patients/sites were considered for inclusion.

Results

After screening based on the inclusion criteria, ten RCTs were included. Low heterogeneity was observed in study characteristics, outcome variables, and estimation scales (I2 = 27.2%, P = 0.19). The qualitative and meta-analysis results showed that PRF increased the effect of implant stabilizers after implant surgery.

Conclusions

The results of the present systematic review and meta-analysis suggest that PRF can increase implant stability after implant surgery. PRF may also have a role in accelerating bone healing and tends to promote new bone formation at the implant site.

Comparison of the effects of three different xenogeneic bone grafts used in sinus augmentation simultaneous with dental implant placement on the survival of the implants and the dimensional changes of the region

BACKGROUND

Xenografts can be produced in various particle sizes by using different bone types. Currently, there is no consensus about the ideal type of xenograft for sinus augmentations, and this choice depends on the personal experience of clinicians. This retrospective study aimed to evaluate the effects of three different xenografts used in sinus augmentation simultaneously with implant placement on the survival of the implants and the dimensional changes of the region.

METHODS

One hundred nine sinus augmentations and 164 implants were evaluated in 76 patients. Three different xenografts were used: 41 Gen-Os^® (250-1000µm, Corticocancellous; Tecnoss, Giaveno, Turin, Italy), 35 Bio-Oss^® (1000-2000µm, Cancellous; Geistlich Biomaterials italia S.r.l., Vicenza, Italy) and 33 Apatos-Cortical^® (600-1000µm, Cortical; Tecnoss). The preoperative, postoperative, and follow-up (21±8.8 month) radiographs were evaluated for the dimensional changes and the implant survivals. The data were statistically analyzed.

RESULTS

Among the implant failures; 3 (5.6%) in 53 implants in Apatos, 2 (3.6%) in 55 implants in Bio-Oss, 9 (16%) in 56 implants in Gen-Os, and 14 (8.5%) total implant failures were observed. This difference between the groups was statistically significant and was due to the high loss rate in the Gen-Os (P=0.044). There was a mean difference of -1.8±1.5mm between the measured bone heights on postoperative day (14.2±2.4mm) and the last follow-up (12.4±2.5 mm). While the loss of height was not affected due to the graft type (P=0.981), the general 12.6% vertical loss was statistically significant (P<0.0001), also the length of implants placed reduced this loss (P=0.036).

CONCLUSIONS

Within the limits of this retrospective study, it can be concluded that: 1) The sinus augmentation procedures with thicker particle size grafts achieved higher success rate; and 2) over the time, 12.6% loss may occur in the height of grafted area.

Effect of increasing mineralization on pre-osteoblast response to native collagen fibril scaffolds for bone tissue repair and regeneration

With limited availability of auto- and allografts, there is increasing demand for alternative bone repair and regeneration materials. Inspired by a mimetic approach, the utility of producing engineered native protein scaffolds is being increasingly realized, demonstrating the need for continued research in this field. In previous work, we detailed a process for producing mineralized collagen scaffolds using tendon to create collagen templates of highly aligned, natively crosslinked collagen fibrils. The process produced mineral phase closely matching that of native bone, and integration of mineral with the collagen template was demonstrated to be easily controlled, allowing scaffolds to be mechanically tuned. In the current study, we have extended this work to investigate how variation in the mineralization level of these scaffolds affects the osteogenic response of pre-osteoblastic cells. Scaffolds were produced under three treatment groups, where collagen templates underwent 0, 5, or 20 mineralization cycles. Scaffolds in each treatment group were cultured with MC3T3-E1 cells for 1, 7, or 14 days. Morphologic assessment under SEM indicated decreased attachment to the mineralized scaffolds, supported by DNA results showing a significant drop between culture days 1 and 7 for mineralized scaffolds only. For adherent cells, increasing scaffold mineralization also delayed cell spreading. While mineralization presented a barrier to cell coverage of scaffolds, it increased osteogenic activity, with cells on the mineralized scaffolds showing significantly greater alkaline phosphatase activity and osteocalcin production. Understanding how increasing collagen mineralization effects pre-osteoblast function may enable design of more advanced mineralized collagen scaffolds for bone repair and regeneration.

Surgical treatment of peri-implantitis defects with two different xenograft granules: A randomized clinical pilot study

Objectives

To investigate whether xenograft EB (EndoBon) is non‐inferior to xenograft BO (Bio‐Oss) when used in reconstructive surgery of peri‐implant osseous defects.

Materials and methods

Dental patients with one implant each demonstrating peri‐implantitis were randomized to receive surgical debridement and defect fill with either BO or EB. Changes in bone level (BL) and intrabony defect depth (IDD) evaluated radiographically were the primary outcomes. The secondary outcomes included changes in probing pocket depth (PPD), bleeding on probing (BoP), and suppuration on probing (SoP). All outcomes were recorded before treatment and at 6 and 12 months post‐treatment.

Results

Twenty‐four patients (n = 11 BO, n = 13 EB) completed the study. Both groups demonstrated significant within‐group improvements in all clinical and radiographic parameters at 6 and 12 months (p ≤ .001). At 12 months, both groups presented with IDD reductions of 2.5–3.0 mm on average. The inter‐group differences were not statistically significant at all time points and for all the examined parameters (p > .05). While the radiographic defect fill in both groups exceeded > 1 mm and can be considered treatment success, successful treatment outcomes as defined by Consensus Reporting (no further bone loss, PPD ≤ 5 mm, no BOP, and no SoP) were identified in 2/11 (18%) BO and 0/13 (0%) EB individuals (Fisher's exact test, p = .199).

Conclusions

Within the limitations of this pilot study, the application of xenograft EB showed to be non‐inferior to xenograft BO when used in reconstructive surgery of peri‐implant osseous defects.

Does the Use of High-Temperature-Processed Xenografts for Ridge Augmentation Result in Ridge Width Stability Over Time?

PURPOSE

Alveolar ridge augmentation is often required before implant placement. The purpose of the present study was to determine whether maxillary and mandibular ridge augmentation with a high-temperature xenograft remains stable over time.

MATERIALS AND METHODS

A retrospective case series was performed of subjects who had undergone maxillary anterior or posterior ridge augmentation with a high-temperature xenograft (HTX). The primary predictor variable was the HTX. The primary outcome variable was the ridge width, measured T0 (before augmentation), T1 (immediately after augmentation), T2 (4 to 6 months after augmentation), and T3 (>4 years after augmentation). The secondary outcome variable was implant success. Analysis of variance and linear regression analysis were used to determine significance. A P value < .05 was considered statistically significant.

RESULTS

A total of 31 patients (age, 52.4 ± 18 years; 61.3% women) were identified who had undergone ridge width augmentation performed using HTX. Of these, 23 had cone-beam computed tomography scans available 4 to 10 years after augmentation had been performed. At the anterior maxilla, the initial ridge augmentation (T1) was 4.7 ± 1.3 mm, which had decreased to 3.7 ± 1.0 mm within 6 months of augmentation (T2) and to 3.3 ± 1.1 mm after an average of 7 years (T3) of follow-up (P < .05). At the posterior mandible, the initial ridge augmentation was 5.4 ± 0.9 mm, which had decreased to 4.1 ± 0.7 mm within 6 months of augmentation and to 3.5 ± 1.0 mm at an average of 7 years of follow-up. A total of 61 implants had been placed in these 23 patients, 3 (4.9%) of which had failed to integrate.

CONCLUSIONS

The use of HTX does result in long-term stability for ridge augmentation.

High Potential of Bacterial Adhesion on Block Bone Graft Materials

Bone graft infections represent a challenge in daily clinics, resulting in increased patient discomfort and graft removal. The aim of this study was to investigate the initial adhesion of five representative pathogens on three different block bone graft materials (xenogeneic, alloplastic and allogeneic) and to assess if chlorhexidine (CHX) can effectively control the initial bacterial adhesion. Three different block bone grafting materials (Tutobone®, Endobon® and human spongiosa) were incubated with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Pseudomonas aeruginosa in the presence or absence of 0.2% CHX solution. Bacterial adhesion was assessed by the direct counting of the colony-forming units (CFUs) and visualized by scanning electron microscopy (SEM). Overall, the selected bacterial species adhered successfully to all tested bone replacement scaffolds, which showed similar bacterial counts. The lg CFU values ranged from 5.29 ± 0.14 to 5.48 ± 0.72 for E. coli, from 4.37 ± 0.62 to 5.02 ± 0.48 for S. aureus, from 4.92 ± 0.34 to 4.95 ± 0.21 for S. mutans, from 4.97 ± 0.40 to 5.22 ± 0.13 for E. faecalis and from 4.23 ± 0.54 to 4.58 ± 0.26 for P. aeruginosa. CHX did not interfere with initial microbial adhesion, and yet it killed all adhered bacterial cells. Thus, CHX can be used to prevent subsequent biofilm infections.

Bone Levels Are Preserved After Simultaneous Sinus Elevation at Time of Implant Placement

PURPOSE

The purpose of this study was to confirm that after simultaneous implant placement and vertical bone augmentation in the posterior maxilla, the immediate postoperative bone height is maintained after 2 to 3 years of follow-up.

PATIENTS AND METHODS

Consecutive patients treated with implant placement in the posterior maxilla were evaluated. Cone-beam scans were taken preoperatively; immediately after implant placement; and for the sinus-grafted cases, 2 to 3 years after surgery. Crestal bone heights were measured. Patients were grouped according to the use of sinus augmentation or no sinus augmentation at the time of implant placement.

RESULTS

The increase in bone height was significant in the graft group when we compared immediate and 3-year follow-up measurements (P < .00001). In the graft group, there were no significant differences in bone height when we compared the immediate and 3-year follow-up periods (P = .31).

CONCLUSIONS

Simultaneous sinus floor elevation with grafting at implant placement results in stable bone levels after 2 to 3 years' follow-up.