Evaluation of Volumetric Changes of Augmented Maxillary Sinus With Different Bone Grafting Biomaterials

Three-dimensional volumetric assessment and stability of simultaneously placed implant following sinus floor augmentation with deproteinized human demineralized tooth matrix or deproteinized bovine bone mineral: a randomized controlled clinical trial

PURPOSE

This study aimed to analyze and compare three-dimensional volumetric bone changes and stability of simultaneously placed dental implants following sinus augmentation using deproteinized human demineralized tooth matrix (dpDTM) and deproteinized bovine bone mineral (DBBM).

METHODS

Twenty-four patients who required lateral maxillary sinus floor augmentation with simultaneous dental implant placement were randomly assigned to receive either dpDTM (n = 12) or DBBM (n = 12). Cone-beam computed tomography and resonance frequency analysis of implant stability were conducted immediately after surgery and 6 months postoperatively. Changes in the graft sinus floor and graft height volumes in the sagittal and coronal views, along with the implant stability quotient (ISQ), were analyzed and compared.

RESULTS

Volumetric graft alteration was comparable between dpDTM (120.33 ± 77.48 mm3) and DBBM (108.51 ± 65.15 mm3) (p = 0.690). Reduction in the average graft height was also comparable: dpDTM group ranged from - 0.59 to - 0.93 mm and the DBBM group ranged from - 0.55 to - 0.82 mm (p > 0.05) at most examined levels. However, greater reduction in the mesial-graft height occurred in the dpDTM group (- 1.08 ± 0.70 mm vs. -0.58 ± 0.39 mm, p = 0.04). The ISQ values increased similarly in both groups to reach 70 at 6 months.

CONCLUSION

dpDTM demonstrated comparable stability in graft volume and height during the healing process compared to DBBM and could serve as a viable alternative to DBBM for sinus floor augmentation with simultaneous implant placement.

The Biomechanical Investigation of Osseointegration Levels in Titanium Implants Simultaniously Placed with Different Bone Grafts

BACKGROUND

Dental implant-supported prostheses have been scientifically accepted and have been a common treatment choice in the case reconstructing of partial or total tooth loss. In additon, bone grafts (alloplast, xsenograft, allograft) are frequently used in implant and sinus lift surgical procedures.

AIM

The aim of this study is to investigate the bone-implant osseointegration levels of titanium implants simultaniously placed with different bone grafts.

MATERIALS AND METHODS

In the study, 32 female S. Dawley rats were divided into four groups. In the control group (n = 8), turned surface implants with a 2.5 mm diameter and a 4 mm length were placed in the tibia of the rats without the use of a graft material. In the experimental groups, bone cavities were opened in the tibias of the rats and a synthetic (alloplast) graft (n = 8), human allograft (n = 8), and bovine xsenograft (n = 8) were placed simultaniously with a 2.5 mm diameter and a 4 mm length turned surface titanium implants. The cavities in the experimental groups were opened with a 4 mm diameter and a 5 mm length. After 8 weeks of recovery, all rats were sacrificed at the end of the experimental period. The implants and surrounding bone tissue were removed. The removed tissue was subjected to biomechanical analysis in order to evaluate bone-implant osseointegration and peri-implant new bone formation. The Kolmogorov-Smirnov test, Kruskal-Wallis test, and Mann-Whitney U-test were used in the study. Significance was evaluated at the P < 0.05 level.

RESULTS

In the biomechanical analyses, it was determined that there was no statistically significant difference between the control group and the other three groups in which different graft materials were applied in terms of bone-implant osseointegration (P > 0.05). In other words, in the biomechanical analyses, no statistical difference was found between any of the groups.

CONCLUSIONS

As a result of this study, it can be thought that different graft materials can be successfully used in peri-implant-guided bone regeneration and may be an alternative to autogenous grafts.

Volumetric changes and graft stability after lateral window sinus floor augmentation: A randomized clinical trial

INTRODUCTION

The present investigation compared the stability and volumetric changes of two different grafting material used for lateral window sinus floor augmentation (LWSFA).

METHODS

Sixteen patients with a total 20 maxillary sinuses in need of LWSFA were included in the present study. The sinuses were grafted with either 100% anorganic bovine bone mineral (ABBM) alone (Group 1) or a mixture (0.8:1 ratio) of ABBM and mineralized cortical allograft (MCA) (Group 2). Cone beam computer tomography (CBCT) was obtained pre-operatively, and at 2-weeks, and 6-months after LWSFA to perform linear measurements including lateral window dimensions, sinus anatomy, residual bone height/thickness (RBH/RBT), and Schneiderian membrane thickness (SMT), among others. Three-dimensional segmentation analysis was used to evaluate changes of bone graft volume/height (GV/GH).

RESULTS

A total of 10 sinuses per group were included in the analysis. No statistically significant difference was found in between groups regarding mean reduction of GV (Group 1: 14.87% ± 16.60%, Group 2: 18.06% ± 9.81%, p = 0.33). Among the linear measurements, only SMT revealed a significant increase after 2-weeks more pronounce in Group 1 (8.70 mm) when compared with Group 2 (5.70 mm) with plausible effect upon LWSFA outcomes. Sinus width showed weak positive correlation with GH reduction after 6 months.

CONCLUSION

This study demonstrated that both ABBM alone and ABBM + MCA represent suitable alternatives for LWSFA with adequate graft stability as they revealed similar volumetric and linear dimensional changes 6 months postoperatively.

The Use of Allograft Bone in the Lateral Approach of Sinus Floor Elevation: A Systematic Review of Clinical Studies

Background and Objectives: The aim of this systematic review was to assess the efficiency of using allografts for sinus lift. Materials and Methods: This systematic review was written under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and recommendation of the Cochrane Handbook for Systematic Reviews of Interventions. Three electronic databases were screened until October 2023. The risk of bias was assessed according to the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) guidelines. Statistical analysis was performed for median bone volume and implant survival rate. Results: From 321 articles retrieved, 7 articles were included in this review. A comparison between freeze-dried bone allograft (FDBA) and deproteinized bovine bone (DBB) for mean bone volume indicated a weighted mean difference (WMD) of -0.17 [-0.69, 0.36] (95% confidence interval (CI)), p = 0.53. For implant survival rate, a comparison was made between FDBA and autogenous bone indicating a risk ratio (RR) of 1.00 [0.96, 1.05] (95% CI), p = 1.00. Conclusions: The available evidence suggested that allograft bone can be used in sinus lift procedures. The results obtained are insufficient to compare with other types of bone graft, requiring a longer follow-up time. Future clinical trials are needed in order to evaluate the advantages of using allograft bone.

Three-dimensional volumetric assessment of hard tissue alterations following horizontal guided bone regeneration using a split-thickness flap design: A case series

OBJECTIVES

To analyze morphological, volumetric, and linear hard tissue changes following horizontal ridge augmentation using a three-dimensional radiographic method.

METHODS

As part of a larger ongoing prospective study, 10 lower lateral surgical sites were selected for evaluation. Horizontal ridge deficiencies were treated with guided bone regeneration (GBR) using a split-thickness flap design and a resorbable collagen barrier membrane. Following the segmentation of baseline and 6-month follow-up cone-beam computed tomography scans, volumetric, linear, and morphological hard tissue changes and the efficacy of the augmentation were assessed (expressed by the volume-to-surface ratio).

RESULTS

Volumetric hard tissue gain averaged 605.32 ± 380.68 mm³. An average of 238.48 ± 127.82 mm³ hard tissue loss was also detected at the lingual aspect of the surgical area. Horizontal hard tissue gain averaged 3.00 ± 1.45 mm. Midcrestal vertical hard tissue loss averaged 1.18 ± 0.81 mm. The volume-to-surface ratio averaged 1.19 ± 0.52 mm³/mm². The three-dimensional analysis showed slight lingual or crestal hard tissue resorption in all cases. In certain instances, the greatest extent of hard tissue gain was observed 2-3 mm apical to the initial level of the marginal crest.

CONCLUSIONS

With the applied method, previously unreported aspects of hard tissue changes following horizontal GBR could be examined. Midcrestal bone resorption was demonstrated, most likely caused by increased osteoclast activity following the elevation of the periosteum. The volume-to-surface ratio expressed the efficacy of the procedure independent of the size of the surgical area.

Characterizing the respiratory-induced mechanical stimulation at the maxillary sinus floor following sinus augmentation by computational fluid dynamics

Background: The relationship between maxillary sinus pneumatization and respiratory-induced fluid mechanics remains unclear. The purpose of this study was to simulate and measure the respiratory-induced mechanical stimulation at the sinus floor under different respiratory conditions and to investigate its potential effect on the elevated sinus following sinus-lifting procedures.

Methods: The nasal airway together with the bilateral maxillary sinuses of the selected patient was segmented and digitally modeled from a computed tomographic image. The sinus floors of the models were elevated by simulated sinus augmentations using computer-aided design. The numerical simulations of sinus fluid motion under different respiratory conditions were performed using a computational fluid dynamics (CFD) algorithm. Sinus wall shear stress and static pressure on the pre-surgical and altered sinus floors were examined and quantitatively compared.

Results: Streamlines with minimum airflow velocity were visualized in the sinus. The sinus floor pressure and the wall shear stress increased with the elevated inlet flow rate, but the magnitude of these mechanical stimulations remained at a negligible level. The surgical technique and elevated height had no significant influence on the wall pressure and the fluid mechanics.

Conclusion: This study shows that respiratory-induced mechanical stimulation in the sinus floor is negligible before and after sinus augmentation.

Clinical and radiographic outcomes following transcrestal maxillary sinus floor elevation with injectable xenogenous bone substitute in gel form: a prospective multicenter study

Purpose

To investigate clinical and radiographic outcomes of transcrestal maxillary sinus floor elevation performed with an injectable xenograft in gel form, analyzing general, local and surgical variables possibly influencing the results.

Methods

Patients with residual crestal height < 5 mm underwent transcrestal sinus floor elevation with xenograft in gel form to allow the placement of a single implant. Simultaneous implant placement was performed when primary stability was ≥ 15 Ncm. Graft height was measured immediately after surgery (T0) and after 6 months of healing (T1). Univariate and multivariate regression models were built to assess associations between clinical variables with implant survival and graft height at T1.

Results

71 patients underwent transcrestal sinus floor elevation and 54 implants were simultaneously placed. Delayed implant placement (at T1) was possible in 5 cases out of 17 (29.4%), whereas in 12 patients (70.6%) implant insertion was not possible or required additional sinus grafting. Implant survival rate, with a follow-up varying from 12 to 32 months after loading, was 100%. Mean pre-operative bone height was 3.8 ± 1.0 mm, at T0 was 13.9 ± 2.2 mm and at T1 was 9.9 ± 2.8 mm. Bone height at T1 was negatively influenced by membrane perforation at surgery (p = 0.004) and positively influenced by immediate implant insertion (p < 0.001).

Conclusions

Transcrestal sinus floor elevation performed with injectable xenograft gel resulted in 100% implant survival rate. However, immediate implant insertion seems a crucial factor to preserve vertical bone gain: one-stage technique seems to be the most predictable approach to optimize clinical outcomes with this approach.

Trial registration clinicaltrials.gov, NCT05305521. Registered 31 March 2022—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05305521.

Patient-specific estimation of the bone graft volume needed for maxillary sinus floor elevation: a radiographic study using cone-beam computed tomography

OBJECTIVE

To develop prediction models for estimating the bone-graft volume needed for sinus floor elevation (SFE) based on the augmentation site, elevation height, and sinus width using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT scans with a medium-to-large field-of-view with bilateral maxillary sinuses partially/entirely visible, acquired from February 2016 to October 2020, were initially screened. Ten defined regions, above the maxillary first (MM₁) and second molar (MM₂) sites, in the sinuses of the included CBCTs were semi-automatically segmented, and the volumes of the regions were automatically measured using the ITK-SNAP program. The sinus widths at the height ranging between 8 and 16 mm from the sinus floor were measured at the MM₁ to MM₂ sites, respectively. Multiple linear regression analyses were performed to establish prediction models for estimating the bone graft volume needed for SFE at the MM₁ and/or MM₂ sites with the sinus width and elevation height as predictors.

RESULTS

A total of 133 scans (224 sinuses) were included. Three developed prediction models, composed of the sinus width and elevation height, explained 89-91% of the variation in the bone graft volumes estimated for SFE at the MM₁, MM₂, and MM₁-MM₂ sites. The mean absolute deviations and absolute percentage deviations between the measured and predicted volumes ranged from 0.12 to 0.28cm³ and from 9.78 to 10.62%, respectively.

CONCLUSION

The proposed prediction models may enable more patient-specific estimation of the bone graft volume needed for SFE.

CLINICAL RELEVANCE

The proposed prediction models could facilitate the preparation of an adequate amount of bone graft material and patient-clinician communication about the cost of bone graft material.

Radiographic and Histomorphometric Evaluation of Biomaterials Used for Lateral Sinus Augmentation: A Systematic Review on the Effect of Residual Bone Height and Vertical Graft Size on New Bone Formation and Graft Shrinkage

The aim of the present systematic review was to investigate the effect of residual bone height (RBH) and vertical bone gain on new bone formation (NBF) and graft shrinkage after lateral sinus lifts using different biomaterials.

METHODS

An electronic search was conducted on three databases to identify randomized controlled trials (RCTs) published until January 2021 with at least one follow-up at 6 months and at least five patients treated, comparing biomaterials used for maxillary sinus augmentation with a lateral approach. Graft volumetric changes, RBH, vertical bone gain, implant failure, and post-operative complications were evaluated. The risk of bias was assessed using the Cochrane tool.

RESULTS

We used 4010 identified studies, of which 21 were RCTs. Overall, 412 patients and 533 sinuses were evaluated. Only three publications had an overall low risk of bias. After 6 months, xenograft (XG) showed the least volume reduction (7.30 ± 15.49%), while autogenous graft (AU) was the most reabsorbed (41.71 ± 12.63%). NBF appeared to not be directly correlated with RBH; on the contrary, the overall linear regression analysis showed that NBF significantly decreased by 1.6% for each mm of postoperative vertical graft gain. This finding suggests that the greater the augmentation, the lower the NBF. A similar tendency, with a regression coefficient even higher than the overall one, was also observed with alloplast (AP) and XG.

CONCLUSIONS

The present results suggested that NBF was essentially independent of preoperative bone height. On the contrary, the smaller the volume was of the graft placed, the higher the amount of new bone formed, and the smaller the graft shrinkage was. Minimizing the augmentation volume might be beneficial to graft healing and stability especially when using AP and XG.

The use of solvent-preserved human and bovine cancellous bone blocks for lateral defect augmentation - an experimental controlled study in vivo

Background

The aim of this study was to compare new bone formation, resorbed bone matrix, and fibrous enclosed residual bone substitute material in laterally augmented alveolar bone defects using allogeneic, pre-treated and cleaned human bone blocks (tested in dogs, therefore considered to be xenogeneic), and pre-treated and cleaned bovine cancellous bone blocks, both with and without a collagen membrane in order to evaluate their augmentative potential.

Methods

Thirty-two critical size horizontal defects were prepared in the mandible of 4 adult foxhound dogs (8 per dog, 4 on each side). After 3 months of healing, the defects were laterally augmented in a split-mouth-design with either human (HXB) or bovine solvent-preserved bone blocks (BXB). Afterwards, defects were randomly covered with a bovine collagenous membrane (HXB + M, BXB + M). After a healing interval of 6 months, percentages of new bone formation, resorbed bone matrix, and fibrous enclosed residual bone substitute material were compared.

Results

Results showed little new bone formation of up to 3.7 % in human bone blocks (HXB 3.7 % ± 10.2, HXB + M 0.3 %± 0.4, BXB, 0.1 % ± 0.8, BXB + M 2.6 % ± 3.2, p = > 0.05). Percentages of fibrous encapsulation were higher in human bone blocks than in bovine bone blocks (HXB 71.2 % ± 8.6, HXB + M 73.71 % ± 10.6, BXB, 60.5 % ± 27.4, BXB + M 52.5 % ± 28.4, p = > 0.05). Resorption rates differed from 44.8 % in bovine bone blocks covered with a membrane to 17.4 % in human bone blocks (HXB 17.4 % ± 7.4, HXB + M 25.9 % ± 10.7, BXB, 38.4 % ± 27.2, BXB + M 44.8 % ± 29.6, p = > 0.05). The use of additional membranes did not significantly affect results.

Conclusions

Within its limitations, results of this study suggest that solvent-preserved xenogenic human and bovine bone blocks are not suitable for lateral bone augmentation in dogs. Furthermore, defect coverage with a membrane does not positively affect the outcome.

Histological Comparison between Biphasic Calcium Phosphate and Deproteinized Bovine Bone on Critical-Size Bone Defects

The limited options for bone repair have led to an extensive research of the field and the development of alloplastic and xenogeneic grafts. The purpose of this study was to evaluate bone repair with two bone substitutes: deproteinized bovine bone (DBB) and biphasic calcium phosphate ceramic (BCP) in critical-size defect. A total of 8-mm defects were made in the parietal bones of rabbits (n=12). The animals were divided into three experimental groups: sham (defect filled with a blood clot), DBB (defect filled with DBB), and BCP (defect filled with BCP). After the experimental periods of 15 and 45 days, the animals were euthanized and submitted to histomorphometric analysis. The total defect area, mineralized tissue area, biomaterial area, and soft tissue area were evaluated. A greater amount of immature bone tissue and biomaterial particles were observed in the BCP group compared to DBB and sham at 45 days (p<0.05). There was no difference in the qualitative pattern of bone deposition between DBB and BCP. However, the sham group did not show osteoid islands along with the defect, presenting a greater amount of collagen fibers as well in relation to the DBB and BCP groups. There was a greater number of inflammatory cells in the DBB at 45 days compared to BCP and sham groups. In conclusion, BCP and DBB are options for optimizing the use of bone grafts for maxillofacial rehabilitation. Bone defects treated with BCP showed greater deposition of bone tissue at 45 days.

Maxillary Sinus Floor Augmentation with Autogenous Bone Graft Compared with a Composite Grafting Material or Bone Substitute Alone: a Systematic Review and Meta-Analysis Assessing Volumetric Stability of the Grafting Material

Objectives

Test the hypothesis of no difference in the volumetric stability of the grafting material following maxillary sinus floor augmentation with autogenous bone graft compared with composite grafting material or bone substitute alone applying the lateral window technique.

Material and Methods

MEDLINE (PubMed), Embase, Cochrane library and hand-search of relevant journals were conducted. Human studies published in English until the 9^th of October 2020 were included. Outcome measures included three-dimensional volumetric changes of the grafting material and potential predictive parameters. Volumetric changes were evaluated by descriptive statistics and meta-analysis including 95% confidence interval.

Results

Electronic search and hand-searching resulted in 102 entries. Four randomized controlled trials with unclear risk of bias fulfilled the inclusion criteria. The volumetric stability of the grafting material was significantly improved by mixing autogenous bone graft with a non-resorbable xenograft compared with autogenous bone graft. Meta-analyses assessing absolute and relative volumetric changes demonstrated no significant differences between autogenous bone graft compared with allogeneic bone graft, synthetic biomaterials combined with autogenous bone graft or used alone. Association between volumetric changes of the grafting material and potential predictive parameters were not assessed in the included studies.

Conclusions

Volumetric reduction of the augmented area seems inevitable following maxillary sinus floor augmentation regardless of the grafting material. The volumetric stability of autogenous bone graft is improved with addition of xenograft compared with autogenous bone graft. However, conclusions drawn from this systematic review should be interpreted with caution since only four studies using three-dimensional radiographic measurements were included.

Effect of amount of biomaterial used for maxillary sinus lift on volume maintenance of grafts

Background

Regardless of the kind of biomaterial used for the graft, it is clear that, over time, the graft undergoes dimensional changes that could influence the final bone volume obtained, which could alter the stability of the installed implants. The aim of the present study was to compared and correlated the graft behavior with the amount (in grams) of xenogeneic and alloplastic biomaterials used in grafts for maxillary sinus lift.

Material and Methods

This retrospective cohort study used 148 CBCT images of 74 grafts from 68 maxillary sinuses lift patients in a university, post-graduate clinic. The weights of biomaterials, categorized in intervals according to amount used, were correlated with the graft volumes at V1 (10 days) and V2 (180 days). Kruskal-Wallis test was used to evaluate the possible bias effect of weight on graft maintenance.

Results

Mean weights of biomaterials used were: Bio-Oss Small® (1.58g); Bio-Oss Large® (1.35g); Endobon® (0.72g); BoneCeramic®+Emdogaim® (0.96g); Cerasorb® (1.13g) and Osteogen® (2.70g). No significant differences (p>0.05). Were found for the influence of these mean amounts in graft maintenance: Bio-Oss Small® (18); Bio-Oss Large® (10); Endobon® (17); BoneCeramic®+Emdogaim® (10); Cerasorb® (11); and Osteogen® (08) at V1 and V2. However, when biomaterials were categorized by intervals, all Cerasorb® interval groups showed statistically significant differences (p<0.001) in graft volume at V2.

Conclusions

The amounts of the biomaterials used could influence the final volume; depending on the biomaterial characteristics. Implant installation was possible with all studied grafts, although graft volume shrinkage should be considered when selecting biomaterial for sinus lift.

Key words:Biocompatible materials; cone beam computed tomography; maxillary sinus; hydroxyapatites.

A reduced healing protocol for sinus floor elevation in a staged approach with deproteinized bovine bone mineral alone: A randomized controlled clinical trial of a 5-month healing in comparison to the 8-month healing

PURPOSE

To investigate the feasibility of reducing the healing time of maxillary sinus floor elevation (MSFE) by a two-stage approach using deproteinized bovine bone mineral (DBBM) alone, based on clinical, histomorphometric, and microradiographic evaluations.

MATERIALS AND METHODS

Twenty consecutive cases with an atrophic posterior edentulous maxilla were randomly assigned to two groups at a ratio of 1:1. The lateral window approach to MSFE with DBBM alone was followed by an 8-month bone-healing period in the control group compared to 5 months in the test group. During implant placement, bone biopsies were harvested from implant osteotomy sites for micro-computed tomography (CT), histological, and histomorphometric evaluations. Cone beam CT (CBCT) scans were performed before and immediately after MSFE and after the bone-healing periods. The implant stability quotient (ISQ) was measured sequentially at implant placement and 1, 3, and 6 months thereafter.

RESULTS

The histomorphometric and microradiographic results showed no significant differences in new bone formation on the augmented sinus floor between the two groups (all Ps > .05), except that trabecular thickness was significantly reduced and trabecular separation significantly increased in the test group (both Ps < .05). The ISQs of both groups increased continuously after implant placement, but the difference was not significant between the groups at each time point. CBCT analyses showed that the extent of volumetric loss was comparable after bone healing for 5 and 8 months (P > .05).

CONCLUSIONS

Within the limitations of this study, the bone-healing time of MSFE with DBBM alone for staged implant placement could be reduced to 5 months instead of 8 or 9 months, based on the histomorphometric, microradiographic, and clinical outcomes; however, impact on long-term implant survival remains unknown and needs further investigation with long-term follow-ups.

Histologic, Histomorphometric, and Clinical Analysis of the Effects of Growth Factors in a Fibrin Network Used in Maxillary Sinus Augmentation

This randomized controlled clinical trial evaluated the effect of mineralized plasmatic matrix (MPM), comprised of synthetic graft and platelet concentrates, on new bone formation and volume stability over time in maxillary sinus lifting (MSL). Unilateral MSL was performed in 20 patients with either beta-tricalcium phosphate (β-TCP) or MPM grafts (10 sinuses each). Six months postsurgery, specimens were obtained with a trephine bur prior to implant placement in 39 cases. Volumetric changes in sinus augmentation were analyzed between 1 week (T-I) and 6 months (T-II) postsurgery. Histomorphometric and histological analyses of biopsy samples revealed mean new bone percentages of 35.40% ± 9.09% and 26.92% ± 7.26% and residual graft particle areas of 23.13% ± 6.16% and 32.25% ± 8.48% in the MPM and β-TCP groups, respectively (p < 0.05). The mean soft-tissue areas in the MPM and β-TCP groups were 41.48% ± 8.41% and 40.83% ± 8.86%, respectively (p > 0.05). Graft reductions between baseline and 6-months postprocedure in the β-TCP and MPM groups were 17.12% ± 13.55% and 14.41% ± 12.87%, respectively, with significant graft volume reduction observed in both groups (p < 0.05) while there is no significant difference between MPM and β-TCP groups (p > 0.05). Thus, MPM, representing growth factors in a fibrin network, increases new bone formation and has acceptable volume stability in MSL procedures

Bovine Bone Promotes Osseous Protection via Osteoclast Activation

The current study aimed at investigating the long-term biological mechanisms governing bone regeneration in osseous defects filled with bovine bone (BB). Tooth extraction sockets were filled with BB or left unfilled for natural healing in a C57BL/6 mouse alveolar regeneration bone model (n = 12). Seven weeks later, the alveolar bone samples were analyzed histologically with hematoxylin/eosin and tartrate-resistant acid phosphatase staining. A separate group (n = 10) was used for RNA sequencing. Osteoclast inhibition was induced by zoledronic acid (ZA) administration at 2 wk postextraction in a third group (n = 28) for examination of osseous changes and cellular functions with micro-computed tomography and quantitative reverse transcription polymerase chain reaction, respectively. Histological and radiological osseous healing was observed in both BB-filled and normal-healing sockets. However, BB regenerated bone showed significant robust expression of genes associated with bone homeostasis and osteoclasts' function. Osteoclasts' inhibition in BB-filled sockets led to decreased bone resorption markers and reduced bone formation to a greater extent than that observed in osteoclasts' inhibition with natural healing. BB displays long-term biologically active properties, despite a naive osseous histological appearance. These include activation of osteoclasts, which in turn promotes osseous remodeling and maturation of ossified bone.

Long-term evaluation of three-dimensional volumetric changes of augmented severely atrophic maxilla by anterior iliac crest bone grafting

PURPOSE

The purpose of this study was to evaluate long-term three-dimensional graft resorption following reconstruction of the severely atrophic maxilla with anterior iliac crest bone grafting.

METHODS

Twenty-two patients (13 males), who underwent autogenous bone grafting and implant placement to their severely atrophic maxillary alveolar ridges were identified and included in the study. Pre- and postoperative cone-beam computed tomography (CBCT) scans of 40 recipient grafting sites were evaluated to calculate volumetric changes over time. CBCT scans were performed preoperatively (V0) and one week (V1), three months (V2), one year (V3), and three years (V4) following the augmentation operation.

RESULTS

The average graft resorption from V1 to V2, V1 to V3, and V1 to V4 was 31.42%, 33.96%, and 37.96%, respectively. Initial graft volume reduction within the first three months was statistically higher compared to other postoperative periods (P<0.013). The rate of resorption reduced slightly from the third month of the surgery (V2) (P>0.013). There was no statistical difference between resorption volume and gender, type of prosthesis, the presence of vestibuloplasty, or patient age (P>0.05).

CONCLUSION

The overall success rate of the iliac bone block grafts was found to be high. The volumetric resorption rates associated with the graft were favourable for the reconstruction of the maxilla and for permitting the placement of dental implants three months after augmentation. The highest graft resorption was found at the third postoperative month. Placement and loading of the implants reduced the resorption rate slightly over time.

Reconstruction of a Large Posttraumatic Mandibular Defect Using Bone Tissue Engineering With Fresh-Frozen Humeral Allograft Seeded With Autologous Bone Marrow Aspirate and Vascularized With a Radial Forearm Flap

INTRODUCTION

Currently, vascularized autologous bone transplantation is considered the gold standard for large mandibular continuity defect reconstruction. Donor site morbidity is a major concern. Therefore, bone tissue engineering (BTE) seems to be the ideal solution. Fresh-frozen bone allograft is the closest material to autologous bone. The purpose of this clinical report is to show a new technique of large mandibular continuity defect reconstruction using a fresh-frozen humeral allograft seeded with autologous iliac bone marrow aspirate and vascularized with a radial forearm flap.

METHODS

A 33-year-old man presented with severe cranio-facial trauma resulting in several fractures of the facial skeleton including a comminuted mandibular fracture from left parasymphysis to left angle, which caused a large continuity defect.

RESULTS

Result at 6 months was aesthetically and functionally satisfactory with osseointegration of the bone graft.

DISCUSSION

The authors chose to use iliac bone marrow aspirate to seed the allograft scaffold since hematopoietic stem cells and mesenchymal stem cell are able to differentiate into osteoblasts, ease of harvest of the iliac crest and its low rate of morbidity. Contemporary biomaterials used for BTE are bioceramic but bone is still the better scaffold to engineer bone and only allografting avoids donor site morbidity. Vascularization is one of the main challenges of BTE; insertion of autologous vascular bundles from pedicle or free flaps is 1 solution. The authors chose the radial forearm flap since the pedicle is long and the authors did not need a great amount of soft tissue.

Automatic three-dimensional analysis of bone volume and quality change after maxillary sinus augmentation

INTRODUCTION

Maxillary sinus augmentation is a widely used surgical procedure to increase the bone volume before implant placement. In order to predict the stability of the implant, analysis of the change in bone volume and quality after a sinus graft procedure is necessary. The purpose of this study was to analyze the change in volume and quality of bone graft material after maxillary sinus augmentation using cone beam computed tomography (CBCT).

METHODS AND MATERIALS

Maxillary sinus lift procedures using bovine bone materials (Bio-Oss, Geistrich, Swiss) without immediate implantation were performed at the Pusan National University Dental Hospital in 22 patients, from 2014 to 2017. CBCT images were captured before surgery (T1), a day after surgery (T2), and after 4 to 7 months at follow-up (T3). The T2 and T3 images were registered to the T1 image using histogram matching and intensity-based registration. A total of 30 sinuses were analyzed three-dimensionally (3-D), using self-made software MATLAB 2018a (MathWorks, Natick, Massachusetts). The volume and structural indices of the bone graft material were measured and analyzed.

RESULTS

The average volume of graft material showed a decrease, while the average gray value showed an increase during the follow-up period, but these changes were not statistically significant. The structural indices of the graft material after histogram matching showed a significant difference in homogeneity, connectivity, thickness, and roughness at the postoperative follow-up.

CONCLUSIONS

The volume and gray value showed no statistically significant changes after the maxillary sinus lift procedures. The results of this study show that structural analysis using histogram matching can be used as a promising tool to analyze the quality of graft materials.

Void space and long-term volumetric changes of maxillary sinus floor augmentation with comparison between hydroxyapatite soaked with bone morphogenetic protein 2 and anorganic bovine xenograft alone

PURPOSE

We hypothesized that the void volume after maxillary sinus floor augmentation (MSFA) with recombinant human bone morphogenetic protein-2 (rhBMP-2) would be larger than that without rhBMP-2, and filled with bone in the long term. The aim of this study was to analyze the occurrence of void space and long-term volumetric changes after MSFA with rhBMP-2 and hydroxyapatite (BMP-2/H).

MATERIAL AND METHODS

In 25 subjects, MSFA was performed with BMP-2/H (group I) or an anorganic bovine xenograft (group II). Computed tomography scans were taken twice, at 3 months (T1) and at least 24 months (T2) after surgery. Total volume (TV), bone volume (BV), and void volume (VV) were measured and analysed statistically.

RESULTS

While similar amounts of graft material were used, the TV was significantly larger in group I than in group II (p = 0.014). The VV showed a tendency to be larger in group I than in group II. VV reduction up to T2 was significantly greater in group I than in group II. Consequently, the BV at T2 was significantly greater in group I than in group II by 36% (p = 0.014).

CONCLUSION

This study showed that our hypothesis was valid. rhBMP-2 is effective for long-term bone regeneration after MSFA.

Evaluation of the survival of implant placement simultaneously with sinus augmentation: relationship in maxillary sinus pathologies

OBJECTIVES

This retrospective study aimed to evaluate the effects of existing maxillary sinus pathologies on the survival rates of dental implants placed simultaneously with sinus augmentation.

METHODS

Cone-beam computed tomography images of 88 patients (34 females, 54 males), who underwent sinus augmentation, were retrospectively analyzed and the patients were divided into two groups: with (pathology group) and without pathology (control group). All maxillary sinus pathologies were recorded and categorized into mucosal thickening ( ≥ 3 mm), antral pseudocyst (polypoid mucosal thickening), and complete opacification. Implant survival rates were evaluated after a mean follow-up period of 28.2 ± 9.8 months based on the patient's records and control radiographs.

RESULTS

A total of 115 maxillary sinuses of 88 patients with 168 dental implants were included in the study. Maxillary sinus pathology was detected in 45 patients in the pathology group and 43 patients in the control group. In the pathology group, one implant was lost out of 82 implants during the 27.8 ± 9.5 months follow-up period, while in the control group, 5 implants were lost out of 86 implants during the 25.1 ± 10 months follow-up period. There was no statistically significant difference in the survival rates between the two groups.

CONCLUSIONS

The study concluded that the presence of pathology in the maxillary sinus before surgery does not affect the survival rates of dental implants placed simultaneously with sinus augmentation. The most common pathology noted included mucosal thickening (61.4%), which was detected in 35 patients.

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.

A 2-year prospective case series on volumetric changes, PROMs, and clinical outcomes following sinus floor elevation using deproteinized bovine bone mineral as filling material

BACKGROUND

A sinus floor augmentation may be indicated when a lack of hard tissue impedes implant placement. Although clinically successful, evidence supporting the long-term three-dimensional stability of the grafted volume is scarce. Second, evidence on the patient's acceptance of this type of treatment is limited.

PURPOSE

First is to evaluate the changes in graft volume after lateral wall sinus lifting based on superimposed cone beam computed tomography (CBCT) images and then to assess patient-reported outcome measures (PROMs) and clinical outcomes.

MATERIALS AND METHODS

Partially edentulous patients in need of a sinus lift and fixed reconstruction on at least two neighboring implants were selected for a prospective case series. Lateral wall sinus augmentation was performed using deproteinized bovine bone mineral (DBBM) as the only filling material. Volumetric changes were quantified on the basis of a preoperative CBCT and three postoperative CBCTs (at 2 weeks, 3 months, and 2 years). PROMs and clinical parameters were registered.

RESULTS

Twenty-two patients (7 males, 15 females; mean age 59 years) participated of which three patients dropped out during the follow up. Graft volumes amounted to 1418.26 mm³ at 2 weeks, 1201.21 mm³ at 3 months, and 1130.13 mm³ at 2 years postoperative pointing to a relative graft volume stability of 79.7%. Swelling was the leading symptom during the first week. A peak in visual analogue scale scores was observed for pain, swelling, and hematoma the day of surgery and 1 day postoperation with a statistically significant decline between days 3 and 7. Hemorrhage and nose bleeding occurred in 18.2% and 27.3% of the subjects, respectively. About 95.5% of the subjects would undergo the treatment again. All implants integrated successfully and demonstrated healthy clinical conditions.

CONCLUSION

Lateral wall sinus augmentation using DBBM as the only filling material is a viable treatment concept given limited graft resorption, good patients' tolerance, and clinical outcomes.

Evaluation of L-PRF combined with deproteinized bovine bone mineral for early implant placement after maxillary sinus augmentation: A randomized clinical trial

PURPOSE

To investigate the effectiveness of adding leukocyte and platelet-rich fibrin (L-PRF) to deproteinized bovine bone mineral (DBBM) for early implant placement after maxillary sinus augmentation.

MATERIALS AND METHODS

Twelve patients requiring two-stage bilateral maxillary sinus augmentation were enrolled to the study. The elevated sinus cavities were randomly grafted with DBBM + L-PRF (test) or DBBM alone (control) in a split-mouth design. Implants were placed in the augmented sites after 4 months in the test group and 8 months in the control group. Bone biopsies were collected during implant placement for histomorphometric evaluation. Resonance frequency analysis was performed immediately after implant placement and at implant loading in both groups. Cone-beam computed tomography was obtained preoperatively and postoperatively for evaluation of graft volume changes.

RESULTS

Both procedures were effective for maxillary sinus augmentation. Cone-beam computed tomography analysis did not reveal differences in graft volume between test and control group at any of the evaluated time points (P > .05). Histological evaluation demonstrated increased percentage of newly formed bone for the test group (44.58% ± 13.9%) compared to the control group (30.02% ± 8.42%; P = .0087). The amount of residual graft in the control group was significantly higher (13.75% ± 9.99%) than in the test group (3.59 ± 4.22; P = .0111). Implant stability quotient (ISQ) immediately after implant placement was significantly higher in the control group (75.13 ± 5.69) compared to the test group (60.9 ± 9.35; P = .0003). The ISQ values at loading did not differ between the groups (P = .8587). Implant survival rate was 100% for both groups.

CONCLUSION

The addition of L-PRF to the DBBM into the maxillary sinus allowed early implant placement (4 months) with increased new bone formation than DBBM alone after 8 months of healing.

A prospective study on ultra-wide diameter dental implants for immediate molar replacement

BACKGROUND

Although wide diameter implants are well documented, little is known about ultra-wide diameter implants (>6 mm). This study evaluates the clinical outcome of ultra-wide diameter implants, placed in molar extraction sockets.

MATERIALS AND METHODS

Ultra-wide diameter implants (7-9 mm) were placed immediately after molar extraction in a 1-stage protocol, without raising a flap or using any bone grafts. After 4 months, the implant was loaded with a single screw-retained crown. Bone loss was evaluated using peri-apical radiographs. Plaque and bleeding were recorded. Crown and papilla dimensions were measured and compared with the contra-lateral tooth.

RESULTS

Fifty-one patients (36 male and 15 female), mean ages 61 years old, were treated with 26 implants in the maxilla and 25 implants in the mandible. The majority had a thick (#19) or medium (#31) biotype. After a mean-follow-up period of 23 months, the mean bone level was located 1.16 mm apical of the implant-abutment junction (SD 0.42, range 0.00-2.45) while the actual bone remodeling associated with socket healing resulted in a mean coronal movement of the bone level of 0.15 mm. The mean insertion torque was 116 Ncm (SD 53, range 10-250). There were no differences in papilla height (P = .55), crown length (P = .32), zenith (P = .84), and bucco-palatal dimensions (P = .38). There was a significant difference in the mesio-distal dimension (P = .01). Mean probing depth was 2.59 mm at the implant and 2.23 mm at the contra-lateral tooth (P = .001). There was significantly more plaque at the tooth compared to the implant (P = .01), but there was no significant difference in terms of bleeding on probing (P = .08). Patient satisfaction was high with 72.5% of the patients experiencing no problems at all.

CONCLUSIONS

Ultra-wide diameter implants have a predictable outcome, demonstrating very little bone loss. Papilla and crown dimensions were comparable to the contra-lateral natural tooth.

Surgeons' Performance Determining the Amount of Graft Material for Sinus Floor Augmentation Using Tomography

This study aimed to assess the performance of surgeons in determining the amount of graft material required for maxillary sinus floor augmentation in a preoperative analysis using cone-beam computed tomography images. A convenience sample of 10 retrospective CBCT exams (i-CAT®) was selected. Scans of the posterior maxilla area with an absence of at least one tooth and residual alveolar bone with an up to 5 mm height were used. Templates (n=20) contained images of representative cross-sections in multiplanar view. Ten expert surgeons voluntarily participated as appraisers of the templates for grafting surgical planning of a 10 mm long implant. Appraisers could choose a better amount of graft material using scores: 0) when considered grafting unnecessary, 1) for 0.25 g in graft material, 2) for 0.50 g, 3) for 1.00 g and 4) for 1.50 g or more. Reliability of the response pattern was analyzed using Cronbach's a. Wilcoxon and Mann-Whitney tests were performed to compare scores. Regression analysis was performed to evaluate whether the volume of sinuses (mm3) influenced the choose of scores. In the reliability analysis, all values were low and the score distribution was independent of the volume of the maxillary sinuses (p>0.05), which did not influence choosing the amount of graft material. Surgeons were unreliable to determine the best amount of graft material for the maxillary sinus floor augmentation using only CBCT images. Surgeons require auxiliary diagnostic tools to measure the volume associated to CBCT exams in order to perform better.

Hydrophilicity, Viscoelastic, and Physicochemical Properties Variations in Dental Bone Grafting Substitutes

The indication-oriented Dental Bone Graft Substitutes (DBGS) selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties’ influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA) of xenograft (cerabone^®), synthetic (maxresorb^®), and allograft (maxgraft^®, Puros^®) blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone^® and maxresorb^® blocks showed a slight height decrease in wet state, whereas both maxgraft^® and Puros^® had an almost identical height increase. In addition, cerabone^® and maxresorb^® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft^® and Puros^® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone^®, Bio-Oss^®, NuOss^®, SIC^® nature graft) and synthetic DBGS granules (maxresorb^®, BoneCeramic^®, NanoBone^®, Ceros^®). The highest level of hydrophilicity was detected in cerabone^® and maxresorb^®, while Bio-Oss^® and BoneCeramic^® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this study initiates a new insight into the DBGS differences and their importance for successful clinical results.

Comparative study of volumetric changes and trabecular microarchitecture in human maxillary sinus bone augmentation with bioactive glass and autogenous bone graft: a prospective and randomized assessment

The aim of this study was to compare the volumetric changes and the new bone microarchitecture in human maxillary sinuses augmented with bioactive glass (Biogran) alone, bioactive glass combined with autogenous bone graft (1:1), or autogenous bone graft alone. Twelve maxillary sinuses were grafted with bioactive glass (group 1), nine with bioactive glass mixed with autogenous bone graft 1:1 (group 2), and 12 with autogenous bone graft (group 3). Patients underwent cone beam computed tomography 15days after the procedure to determine the initial volume of the graft (T1) and again 6 months later (T2). Biopsies were obtained at the time of dental implant placement and were subjected to micro-computed tomography. The volumetric change was 44.2% in group 1, 37.9% in group 2, and 45.7% in group 3 (P>0.05). The trabecular microarchitecture results showed that the materials used in groups 1 and 2 were good bone substitutes. However, the addition of 50% bioactive glass to autogenous bone graft improved the microarchitecture of the graft. Furthermore, the results for volumetric changes indicated that bioactive glass, its association with autogenous bone graft in a 1:1 ratio, and autogenous bone graft alone have similar resorption.

A prospective controlled trial comparing xenograft/autogenous bone and collagen-stabilized xenograft for maxillary sinus augmentation-Complications, patient-reported outcomes and volumetric analysis

OBJECTIVE

Compare maxillary sinus augmentation (MSA) using two different materials-anorganic bovine bone mineral (ABBM) + autogenous bone (AB) (control group) vs. collagen-stabilized ABBM (test group) in terms of complications, patient-reported outcome measures (PROMs) and volumetric analysis.

MATERIALS AND METHODS

Sixty patients underwent sinus augmentation (30 control + 30 test group). Intra- and postoperative complications were recorded. PROMs measured the impact of grafting on daily activities, pain and morbidity. CT scans were used to measure graft volume, ridge height, material selection and degree of contact of graft-to-surrounding sinus walls. Dental implant placement parameters were also recorded.

RESULTS

All complications were minor and did not prevent completion of the augmentation or subsequent implant placement. Schneiderian membrane perforation was the most frequently encountered complication. Both treatment groups reported moderate limitation in the 1st 48 hr post-surgery but little or none by day 3 or 4. Jaw opening, chewing and bruising were significantly higher in the control group. The impact on work and social life was moderate initially but reduced to little or none by the 2nd day. Mild to moderate pain and interference to daily activities were reported for the first 3 days requiring the use of NSAIDs only. A mean graft volume of 1.46 cm³ (±0.77) was calculated in the control group and 1.27 cm³ (±0.65) in the test group. Extent of contact between graft and surrounding sinus walls had a significant impact on bone volume. Shorter (8 mm) implants were utilized more frequently in the test group, which was also more likely to require additional vertical augmentation, but this was not statistically significant.

CONCLUSION

MSA using a lateral wall approach is safe and associated with mild to moderate pain and restrictions to daily activities for 48-72 hr. Patients' reports of morbidity were greater with autogenous bone harvesting. Collagen-stabilized ABBM provides comparable bone volume to AB + ABBM that is sufficient for placement of implants of adequate size with no need for further vertical augmentation. Engaging the surrounding sinus walls had a significant positive impact on graft volume.

Clinical and 3-Dimensional Radiographic Evaluation of Autogenous Iliac Block Bone Grafting and Guided Bone Regeneration in Patients With Atrophic Maxilla

PURPOSE

To evaluate the rate of graft resorption in autogenous iliac bone grafting (IBG) and guided bone regeneration (GBR) in patients with atrophic maxillae.

MATERIALS AND METHODS

We performed a retrospective study involving patients requiring implant placement who underwent IBG or GBR. Volumetric changes of the graft sites were evaluated by imaging studies. The primary predictor and outcome variables were augmentation technique and rate of volumetric resorption, respectively. Secondary outcome variables included bone gain, success of grafting, insertion torque of implants, and requirement for vestibuloplasty.

RESULTS

The sample comprised 39 patients (21 with GBR and 18 with IBG). One patient in the IBG group had temporary sensory disturbance at the donor site, and one patient in the GBR group had late exposure of the nonresorbable membrane. The average values of percent volume reduction in the GBR and IBG groups were 12.26% ± 2.35% and 35.94% ± 7.94%, respectively, after healing and 15.87% ± 1.99% and 41.62% ± 6.97%, respectively, at last follow-up. The IBG group exhibited a significantly higher reduction in bone volume than the GBR group at both time points (P = .001). The mean values of horizontal and vertical bone gain after healing in the IBG group were significantly higher than those in the GBR group (P = .006 and P = .001, respectively). The mean implant torque during implant placement in the GBR group was significantly higher than that in the IBG group (P = .024). There was no significant difference in the requirement for vestibuloplasty between the two groups (P > .05).

CONCLUSIONS

Although both hard tissue augmentation approaches provide an adequate volume of bone graft for implant insertion, IBG results in greater graft resorption at maxillary augmented sites than GBR. Clinicians should consider the differences in the extent of graft resorption between the two methods while choosing the treatment approach.