20-Year Follow-up in Maxillary Sinus Floor Elevation Using Bovine-Derived Bone Mineral: A Case Report with Histologic and Histomorphometric Evaluation

Clinical and radiographic assessment of cross-linked hyaluronic acid addition in demineralized bovine bone based alveolar ridge preservation: A human randomized split-mouth pilot study

PURPOSE

To investigate clinically and radiographically at 4 months post-operatively the outcomes of mixing demineralized bovine bone material (DBBM) with cross-linked hyaluronic acid in alveolar ridge preservation.

MATERIAL AND METHODS

Seven patients presenting bilateral hopeless teeth (14 teeth) were enrolled in the study, the test site contained demineralized bovine bone material (DBBM) mixed with cross-linked hyaluronic acid (xHyA) while the control site contained only DBBM. 4 months post-operatively prior to implant placement a Cone beam computed tomography (CBCT) scan was recorded and compared to the initial scan to assess the volumetric and linear bone resorption that occurred in both sites. Clinically, sites that needed further bone grafting at the implant placement stage were recorded. Differences in volumetric and linear bone resorption between both groups were assessed using Wilcoxon signed rank test. McNemar test was also used to evaluate difference in bone grafting need between both groups.

RESULTS

All sites healed uneventfully, volumetric and linear resorption differences between the baseline and 4 months post-operatively were obtained for each site. The mean volumetric and linear bone resorption were respectively 36.56 ± 1.69%, 1.42 ± 0.16 mm in the controls sites and 26.96 ± 1.83%; 0.73 ± 0.052 mm in the tests sites. The values were significantly higher among controls sites (P=0.018). No significant differences were observed in the need for bone grafting between both groups.

CONCLUSION

Cross-linked hyaluronic acid (xHyA) appears to limit the post-extractional alveolar bone resorption when mixed with DBBM.

Horizontal Alveolar Ridge Augmentation with Xenogenic Block Grafts Compared with Autogenous Bone Block Grafts for Implant-retained Rehabilitation: a Systematic Review and Meta-Analysis

Objectives

The objective of the present systematic review and meta-analysis was to test the 0-hypothesis of no difference in implant treatment outcome after horizontal alveolar ridge augmentation with xenogenic block compared with autogenous bone block.

Material and Methods

A literature search was conducted using PubMed, Embase and Cochrane Library databases in combination with a hand-search of relevant journals until 25^th of January 2022. Comparative and non-comparative studies evaluating horizontal alveolar ridge augmentations with xenogenic blocks were included. Quality and risk of bias were evaluated by Cochrane Collaboration's revised tool and Newcastle-Ottawa scale.

Results

Meta-analysis revealed no statistically significant difference in implant survival rate after more than 6 months of functional implant loading (P = 0.71), no difference in alveolar ridge width (P = 0.07) or gain of alveolar ridge width at re-entry (P = 0.13). Non-comparative studies revealed moderate to high short-term implant survival rate and gain in alveolar ridge width, however, complications including dehiscences, graft exposure and graft failure were observed in several studies.

Conclusions

No significant difference could be identified in short-term implant treatment outcome following horizontal alveolar ridge augmentation using xenogenic block compared with autogenous bone block with the limited data available. A high incidence of healing complications and implant failures necessitates further investigation, as well as long-term results on implant survival rate.

Effect of Alleviating Fibrosis with EGCG-Modified Bone Graft in Murine Model Depended on Less Accumulation of Inflammatory Macrophage

In response to current trends in the modification of guided bone regeneration (GBR) materials, we aimed to build upon our previous studies on epigallocatechin-3-gallate (EGCG) by immersing a commonly used bone graft primarily composed of hydroxyapatite (HA) in EGCG solution, expecting to obtain superior bone material integration after implantation. Bone grafts are commonly used for bone repair, in which the bone extracellular matrix is stimulated to promote osteogenesis. However, due to its profibrosis effect, this osteoconductive material commonly exhibits implant failure. In addition to providing a basic release profile of EGCG-modified bone graft (E-HA) to clarify the relationship between this material and the environment, we have examined the integration effect via subcutaneous implantation experiments. In this manner, we have assessed the aggregation of proinflammatory macrophages, the formation of fibrous capsules, and an enhanced cell viability observed in cultured RAW 264.7 cells. Among these results, we focus on proinflammatory macrophages due to their close relationship with fibrosis, which is the most important process in the immune response. Immunofluorescent staining results showed that E-HA substantially compromised the formation of fibrous capsules in hematoxylin-eosin-stained sections, which exhibited less proinflammatory macrophage recruitment; meanwhile, the cell viability was improved. This work lays the foundation for future studies on GBR.

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.

Clearance of Bone Substitute in Gel Form Accidentally Dispersed into the Sinus Cavity during Transcrestal Maxillary Sinus Floor Elevation: Two-Case Report

Sinus membrane perforation is the most frequent intraoperative complication occurring during maxillary sinus floor elevation. Although numerous techniques for perforation management are present, grafting material dissemination may still occur, representing a potential trigger factor leading to acute or chronic sinusitis. This case report describes two cases of xenogeneic bone substitute in gel form accidentally dispersed into the sinus cavity during maxillary sinus floor elevation with a transcrestal approach. In both cases, immediately postoperative radiographic imaging showed an important amount of gel graft dislodged into the sinus cavity as a consequence of hidden perforations that remained undetected during surgery. Patients were monitored for 6 months after surgery and reported no signs or symptoms related to possible sinus disease. Control radiographs showed no sinus membrane hypertrophy and/or presence of residual disseminated gel, confirming complete clearance of the accidentally dispersed graft through the ostiomeatal complex. In order to minimize postoperative complications, bone substitutes in gel form could represent an interesting alternative to granular grafts for their easier clearance from the maxillary sinus cavity in case of accidental dissemination during sinus augmentation procedures.

Evaluation of hard tissue 3-dimensional stability around single implants placed with guided bone regeneration in the anterior maxilla: A 3-year retrospective study

STATEMENT OF PROBLEM

Guided bone regeneration (GBR) is widely used to reconstruct peri-implant bone defects in the esthetic zone. However, the dimensional stability of this bone-biomaterial composite is not fully understood.

PURPOSE

The primary aim was to evaluate the hard tissue 3-dimensional (3D) stability around single implants placed with simultaneous GBR by using deproteinized bovine bone mineral (DBBM) in the anterior maxilla and explore possible influencing factors.

MATERIAL AND METHODS

The records of patients who had received implants in the anterior maxilla from January 2015 to March 2016 were reviewed retrospectively. The change in volume and thickness of the facial hard tissue were analyzed. To explore possible influencing factors, the thickness and surface area of facial graft were measured, and the time point at which implants were placed and the healing protocol were recorded. Secondary outcome measures were peri-implant marginal bone loss, bleeding on probing (BOP), and pink esthetic score (PES). Statistical analysis was conducted by using the Student t test, Mann-Whitney U test, Kruskal-Wallis test, or generalized estimating equation analysis (α=.05).

RESULTS

Fifty-five participants were included in this study, and no implants had been lost after 3 years. BOP was present in 10 (18.2%) participants. The mean ±standard deviation PES of all implants for this study was 11.0 ±2.1. The mean ±standard deviation percentage of residual hard tissue volume was 36.9 ±23.5%, with a significant difference found between time points before 9 months (P<.05). Type 3 implant placement (OR=1.449, P=.031) was found to have a higher percentage of residual hard tissue volume. A greater reduction of the facial hard tissue thickness was observed in participants with thicker postoperative facial grafting (OR=1.463, P=.001). No statistically significant difference was found between the facial, palatal, mesial, and distal peri-implant sites in terms of marginal bone loss (P>.05).

CONCLUSIONS

Although single-tooth implant placement combined with GBR using DBBM in the anterior maxilla offered satisfactory esthetic and functional outcomes after a 3-year follow-up, significant hard tissue volume and thickness reduction in grafted sites was detected, especially during the initial 9-month postoperative period. This phenomenon may be correlated with the timing of implant placement and the thickness of the facial graft.