Randomized clinical study assessing two membranes for guided bone regeneration of peri-implant bone defects: clinical and histological outcomes at 6 months

Effects of different oral barrier membranes on the efficacy and safety of guided bone regeneration in patients with dental implants: a systematic review and meta-analysis

OBJECTIVE

This study aims to systematically evaluate the effects of different oral barrier membranes on bone regeneration, focusing on their clinical efficacy and safety during dental implant procedures.

METHODS

A comprehensive search was conducted in PubMed, EMBASE, ScienceDirect, Cochrane Library, CNKI, VIP, and CBM databases for case-control and cohort studies published between January 2002 and March 2025. Two independent researchers screened and extracted data, and statistical analysis was performed using RevMan 5.3. The study was registered in PROSPERO (CRD492390).

RESULTS

A total of 11 clinical controlled and cohort studies with 1,003 patients were included. The absorbable membrane group demonstrated a significantly higher success rate (p < 0.05), greater bone graft thickness (p < 0.05), and fewer adverse reactions (p < 0.05). Meta-analysis showed no significant difference in osseointegration, total mineralised tissue, and non-mineralised tissue (p > 0.05).

CONCLUSION

Absorbable oral barrier membranes exhibit superior safety and efficacy profiles, making them a preferred choice for guided bone regeneration. However, further studies with higher methodological quality and longer follow-up durations are required.

Six-Year Implants Follow-Up After Guided Bone Regeneration Using Autologous Tooth Graft: Innovative Biomaterial for Bone Regeneration Tooth Transformer®

OBJECTIVES

Recently, there has been great interest in teeth and their derivatives as suitable substrates for the treatment of alveolar bone defects. This retrospective study evaluates the clinical and radiographic outcomes of implants inserted in a site that underwent GBR procedure using a tooth derivate material.

MATERIALS AND METHODS

A total of 21 patients received a GBR using an autologous extracted tooth. Four months after the GBR techniques, the implants were inserted and were followed for an average of 5.28 + -1.10 years after loading. The X-ray was analyzed after a period of 63.36 + -13.2 months for a total follow-up period.

RESULTS

A total of 28 implants were inserted. All the implants were clinically functional after the follow-up period. The average bone loss from the X-ray images was 0.1208 + -0.1307.

CONCLUSION

Within the limitations of this study, the use of a tooth as a graft using a tooth transformer device guarantees the production of bone and maintenance over time.

Hard and soft tissue contour changes following simultaneous guided bone regeneration at single peri-implant dehiscence defects using either resorbable or non-resorbable membranes: a 6-month secondary analysis of a randomized controlled trial

OBJECTIVES

To compare radiographic and profilometric outcomes 6 months after simultaneous lateral guided bone regeneration (GBR) at single peri-implant dehiscence defects in the anterior region using either resorbable or non-resorbable membranes.

MATERIALS AND METHODS

In 27 patients with a single tooth gap in the anterior region (second premolar to second premolar in the maxilla) a dental implant was placed. Following implant placement GBR was performed at the buccal aspect using randomly either a resorbable collagen membrane (RES) or a non-resorbable titanium-reinforced ePTFE membrane (N-RES). Radiographic (cone-beam computed tomography; CBCT) measurements were performed to assess the buccal bone thickness immediately after the implant placement with simultaneous GBR (baseline) and 6 months later. Buccal soft tissue thickness was assessed by superimposing surface scans taken at baseline and again 6 months later.

RESULTS

A total of 25 datasets could be assessed for the bone dimensions (n = 12, RES; n = 13, N-RES) and 14 datasets for profilometric changes (n = 7, RES; n = 7, N-RES). Group RES showed a significant mean reduction in buccal bone between baseline and 6 months of 0.8 ± 0.4 mm (p = 0.004). The respective mean reduction for group N-RES amounted to 0.1 ± 0.4 mm (p = 0.581). When comparing the buccal bone changes between both group over time, group RES exhibited greater reduction in comparison to group N-RES (intergroup p = 0.017). Profilometric analyses showed a non-significant trend towards soft tissue gain in group RES 0.6 ± 0.7 mm (p = 0.125). Conversely, N-RES group revealed stability, with a mean change of 0.0 ± 0.3 mm (p = 1.000).

CONCLUSIONS

GBR using non-resorbable membranes seems to provide greater dimensional stability of augmented bone at 6 months re-entry and before implant loading compared to resorbable membranes. The lack of differences in the profilometric outcomes and contour changes may be explained by a partial compensation through an increase in soft tissue thickness with resorbable membranes.

CLINICAL RELEVANCE

GBR using non-resorbable membranes may offer greater dimensional stability of augmented bone compared to resorbable membranes. However, these potential benefits may be offset by a compensatory increase in soft tissue thickness when using resorbable membranes.

Zirconia Barriers in Bone Regeneration Procedures: A Scoping Review

PURPOSE

To identify the current status and development of zirconia barriers in bone augmentation procedures in the maxillofacial area of adult human patients.

MATERIALS AND METHODS

Two independent reviewers conducted an electronic literature search in PubMed/MEDLINE, Web of Science, Scopus, EBSCO, the Cochrane Library, and LILACS databases, as well as a manual search to identify eligible clinical studies up to April 15, 2024. The protocol was designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines.

RESULTS

The initial electronic search resulted in 240 studies. The systematic application of inclusion and exclusion criteria resulted in 6 articles that met the purpose of the study. The included articles were 5 clinical case series and 1 case report, published between 2016 and 2023. Only 4 articles reported histological studies. A total of 40 sites regenerated with zirconium barriers were reported in 30 patients. Results were obtained with variability in bone gain values, between 0.9-8.0 mm horizontally and 1.4-12.0 mm vertically, in addition to a 30% complication rate.

CONCLUSIONS

Although the results obtained in the studies included in this scoping review are favorable with respect to the amount of bone formation and the reduced surgical time required, the number of complications is considered high. Moreover, due to a limited number of patients included in the case series and the short duration of follow-up, additional studies including a control group are required.

ZIF-8-Modified Multifunctional Hydrogel Loading siRNA and DOX for Postoperative Therapy of Maxillofacial Osteosarcoma and Bone Repair

The primary clinical challenges associated with postoperative maxillofacial osteosarcoma include high mortality rates and significant local recurrence. Additionally, patients often exhibit substantial bone defects that are incapable of self-healing, necessitating the implantation of scaffolds. Multifunctional hydrogels, which enable sustained local release of therapeutic agents and enhance scaffold surface properties, demonstrate significant potential for the postoperative management of maxillofacial osteosarcoma. In this study, doxorubicin (DOX) and PD-L1 siRNA were initially loaded into ZIF-8 to synthesize highly stable nanocomplex RNA-DOX@ZIF-8 (RDZ). Subsequently, a multifunctional hydrogel (Gel@RDZ) was fabricated by uniformly mixing RDZ with catechol-modified chitosan. Gel@RDZ exhibits a high drug-loading capacity, excellent viscoelasticity, and strong scaffold adhesion. In a rat femoral defect model, the Gel@RDZ-coated scaffold group demonstrated superior bone regeneration capabilities. Furthermore, in a murine osteosarcoma recurrence model, Gel@RDZ exhibited optimal immune cell infiltration, substantially reduced tumor recurrence, and markedly enhanced the tumor-killing efficacy of CD8+ T cells. Therefore, the development of a multifunctional hydrogel system (Gel@RDZ) provides a comprehensive treatment for postoperative maxillofacial osteosarcoma.

Impact of Implant Design on Outcomes of Simultaneous Guided Bone Regeneration for Dehiscence Defects: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis aimed to determine the implications of implant design on the outcomes of simultaneous guided bone regeneration (GBR) to correct dehiscence defects.

METHODS

A structured search strategy was applied to MEDLINE (PubMed), Cochrane Library, and Embase, to identify prospective clinical trials involving implants with simultaneous GBR to correct dehiscence defects. Data regarding implant characteristics, GBR materials, as well as dehiscence defect dimensions at implant placement and surgical re-entry was collected. Meta-analyses were performed to estimate the pooled mean for (1) baseline dehiscence defect dimensions, (2) changes in defect dimensions at re-entry, and (3) prevalence of complete defect resolution.

RESULTS

4298 unique records were identified, of which 21 studies with 680 implants were included. Despite having comparable baseline defect dimensions, greater height gains were achieved by implants with machined collars (MC) than noncollared (NC) implants (4.40 mm, 95% CI [3.70, 5.11] and 3.23 mm, 95% CI [2.72, 3.75] respectively), with significant subgroup differences (P < .01). Specifically, superior outcomes were observed for MC with space-maintaining geometries. However, there were no significant differences in the changes in defect width, prevalence of complete defect resolution, or the prevalence of postsurgical complication rates (P = .15, .54, and .18 respectively).

CONCLUSIONS

The regenerative outcomes of GBR were influenced by the implant design. Space-maintaining machined collars provide a tenting effect that improves vertical bone gain. While additional research is required to ascertain these findings and integrate choices regarding implant design into clinical decision-making, clinicians may consider replicating this effect to enhance treatment outcomes.

Collagen-Based Medical Devices for Regenerative Medicine and Tissue Engineering

Assisted reproductive technologies are key to solving the problems of aging and organ defects. Collagen is compatible with living tissues and has many different chemical properties; it has great potential for use in reproductive medicine and the engineering of reproductive tissues. It is a natural substance that has been used a lot in science and medicine. Collagen is a substance that can be obtained from many different animals. It can be made naturally or created using scientific methods. Using pure collagen has some drawbacks regarding its physical and chemical characteristics. Because of this, when collagen is processed in various ways, it can better meet the specific needs as a material for repairing tissues. In simpler terms, collagen can be used to help regenerate bones, cartilage, and skin. It can also be used in cardiovascular repair and other areas. There are different ways to process collagen, such as cross-linking it, making it more structured, adding minerals to it, or using it as a carrier for other substances. All of these methods help advance the field of tissue engineering. This review summarizes and discusses the current progress of collagen-based materials for reproductive medicine.

Efficacy of biomaterials for lateral bone augmentation performed with guided bone regeneration. A network meta-analysis

Bone regeneration is often required concomitant with implant placement to treat a bone fenestration, a dehiscence, and for contouring. This systematic review assessed the impact of different biomaterials employed for guided bone regeneration (GBR) simultaneous to implant placement on the stability of radiographic peri-implant bone levels at ≥12 months of follow-up (focused question 1), as well as on bone defect dimension (width/height) changes at re-assessment after ≥4 months (focused question 2). Only randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared different biomaterials for GBR were considered. A Bayesian network meta-analysis (NMA) was performed using a random-effects model. A ranking probability between treatments was obtained, as well as an estimation of the surface under the cumulative ranking value (SUCRA). Overall, whenever the biological principle of GBR was followed, regeneration occurred in a predictable way, irrespective of the type of biomaterial used. A lower efficacy of GBR treatments was suggested for initially large defects, despite the trend did not reach statistical significance. Regardless of the biomaterial employed, a certain resorption of the augmented bone was observed overtime. While GBR was shown to be a safe and predictable treatment, several complications (including exposure, infection, and soft tissue dehiscence) were reported, which tend to be higher when using cross-linked collagen membranes.

Bone regeneration in implant dentistry: Which are the factors affecting the clinical outcome?

The key factors that are needed for bone regeneration to take place include cells (osteoprogenitor and immune-inflammatory cells), a scaffold (blood clot) that facilitates the deposition of the bone matrix, signaling molecules, blood supply, and mechanical stability. However, even when these principles are met, the overall amount of regenerated bone, its stability over time and the incidence of complications may significantly vary. This manuscript provides a critical review on the main local and systemic factors that may have an impact on bone regeneration, trying to focus, whenever possible, on bone regeneration simultaneous to implant placement to treat bone dehiscence/fenestration defects or for bone contouring. In the future, it is likely that bone tissue engineering will change our approach to bone regeneration in implant dentistry by replacing the current biomaterials with osteoinductive scaffolds combined with cells and mechanical/soluble factors and by employing immunomodulatory materials that can both modulate the immune response and control other bone regeneration processes such as osteogenesis, osteoclastogenesis, or inflammation. However, there are currently important knowledge gaps on the biology of osseous formation and on the factors that can influence it that require further investigation. It is recommended that future studies should combine traditional clinical and radiographic assessments with non-invasive imaging and with patient-reported outcome measures. We also envisage that the integration of multi-omics approaches will help uncover the mechanisms responsible for the variability in regenerative outcomes observed in clinical practice.

Evaluation of the clinical and radiographic effectiveness of treating peri-implant bone defects with a new biphasic calcium phosphate bone graft: a prospective, multicenter randomized controlled trial

PURPOSE

Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 40% β-TCP and 60% HA compared to demineralized bovine bone mineral (DBBM).

METHODS

This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent t-test and the χ² test.

RESULTS

Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, P=0.133), postoperative discomfort, or early wound healing. No adverse or fatal complications occurred in either group.

CONCLUSION

The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0006428.

Decontaminative Properties of Cold Atmospheric Plasma Treatment on Collagen Membranes Used for Guided Bone Regeneration

Background cold atmospheric plasma (CAP) is known to be a surface-friendly yet antimicrobial and activating process for surfaces such as titanium. The aim of the present study was to describe the decontaminating effects of CAP on contaminated collagen membranes and their influence on the properties of this biomaterial in vitro. Material and Methods: A total of n = 18 Bio-Gide^® (Geistlich Biomaterials, Baden-Baden, Germany) membranes were examined. The intervention group was divided as follows: n = 6 membranes were treated for one minute, and n = 6 membranes were treated for five minutes with CAP using kINPen^® MED (neoplas tools GmbH, Greifswald, Germany) with an output of 5 W, respectively. A non-CAP-treated group (n = 6) served as the control. The topographic alterations were evaluated via X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Afterward, the samples were contaminated with E. faecalis for 6 days, and colony-forming unit (CFU) counts and additional SEM analyses were performed. The CFUs increased with CAP treatment time in our analyses, but SEM showed that the surface of the membranes was essentially free from bacteria. However, the deeper layers showed remaining microbial conglomerates. Furthermore, we showed, via XPS analysis, that increasing the CAP time significantly enhances the carbon (carbonyl group) concentration, which also correlates negatively with the decontaminating effects of CAP. Conclusions: Reactive carbonyl groups offer a potential mechanism for inhibiting the growth of E. faecalis on collagen membranes after cold atmospheric plasma treatment.

Extraction of high inverted mesiodentes via the labial, palatal and subperiostal intranasal approach：A clinical prospective study

The aim of this study is to provide criteria for the choice of the surgical approach for extraction of high inverted mesiodens. The operation statistics, life quality of postoperative patients, and the operative injury/recovery were compared and analysed. The laser Doppler blood flowmetry, laser speckle contrast imaging, and electric pulp testing were explored to detect the postoperative pulp and gingiva blood supply of adjacent teeth. For the clinician's primary concerns, the surgical time, the volume of osteotomy, and the amount of bleeding in the labial approach group (The p values are 0.0001, <0.0001, and 0.0131, respectively.) and intranasal approach group (All p values were <0.0001.) were significantly less than that in the palatal approach group. However, from the patient's perspective, the postoperative swelling in the labial approach was far more than that in the intranasal approach group (p =0.0044), with unsurprisingly lower satisfaction (p <0.0001). There were no significant differences in pulp and gingival blood supply of adjacent teeth and jaw development. Trauma was manageable in all patients. Within the limitations of the study it seems that extraction of mesiodens by the intranasal approach achieves a delicate balance between reducing surgical trauma and optimizing postoperative recovery.

Guided Bone Regeneration Using a Novel Magnesium Membrane: A Literature Review and a Report of Two Cases in Humans

Guided bone regeneration (GBR) is a common procedure used to rebuild dimensional changes in the alveolar ridge that occur after extraction. In GBR, membranes are used to separate the bone defect from the underlying soft tissue. To overcome the shortcomings of commonly used membranes in GBR, a new resorbable magnesium membrane has been developed. A literature search was performed via MEDLINE, Scopus, Web of Science and PubMed in February 2023 for research on magnesium barrier membranes. Of the 78 records reviewed, 16 studies met the inclusion criteria and were analyzed. In addition, this paper reports two cases where GBR was performed using a magnesium membrane and magnesium fixation system with immediate and delayed implant placement. No adverse reactions to the biomaterials were detected, and the membrane was completely resorbed after healing. The resorbable fixation screws used in both cases held the membranes in place during bone formation and were completely resorbed. Therefore, the pure magnesium membrane and magnesium fixation screws were found to be excellent biomaterials for GBR, which supports the findings of the literature review.

Clinical, radiographic, and esthetic evaluation of immediate implant placement with buccal bone dehiscence in the anterior maxilla: A 1-year prospective case series

OBJECTIVES

To evaluate the clinical, radiographic, and esthetic outcomes of immediate implant placement with buccal bone dehiscence in the anterior maxilla.

METHODS

In this case series, implants were inserted immediately after tooth extraction in sockets with buccal bone dehiscence. Guided bone regeneration (GBR) with a papilla preservation flap and simultaneous connective tissue grafting (CTG) was used. The following outcome variables were measured: mid-facial mucosal recession, probing depth, bleeding on probing, Pink Esthetic Score (PES), marginal bone loss, and thickness of buccal bone plate (TBP).

RESULTS

12 patients were recruited. Stable mid-facial mucosal level (-0.03 ± 0.17 mm) and excellent soft-tissue esthetic outcomes (PES, 9.17 ± 0.72) were achieved at 1 year. The TBP at platform level was 2.01 ± 0.31 mm at 1-year follow up with a resorption rate of 28.90% ± 15.14%.

CONCLUSIONS

Immediate implant placement using GBR performed with a papilla preservation approach and simultaneous CTG is a feasible treatment procedure in compromised extraction sockets in the anterior region. Favorable esthetic outcomes and buccal bone thickness were obtained. Further studies were needed to evaluate the long-term tissue alteration.

Bone Regenerative Potential of Cross-Linked Collagen Membrane in Peri-Implant Osseous Defect: Case Series with Histologic/Micro-Computed Tomographic Findings

The role of a barrier membrane is crucial in guided bone regeneration (GBR) for space creation and cell occlusiveness. Those properties of the membrane should be sustained for a sufficient period. For such purpose, several cross-linked collagen membranes were introduced and demonstrated favorable clinical outcomes. However, histologic data were not sufficient to support the effect of cross-linked collagen membranes. In the present case series, healing after GBR using a cross-linked collagen membrane was investigated in-depth via histologic and micro-computed tomographic (micro-CT) analyses. 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide cross-linked collagen membrane was used in GBR for treating various peri-implant bone defects in seven patients. After 4-7 months of healing, newly formed tissue of hard consistency was observed over the implant platform. This tissue was carefully harvested and assessed. In micro-CT and histological analyses, evident new bone formation was revealed, especially in the vicinity of the collagen membrane. Moreover, it was histologically found that some newly formed bone was in intimate contact with the membrane. Although the exact mechanism of bone regeneration in the present cases was not clearly elucidated, the cross-linked collagen membrane appeared to contribute to ossification in GBR. Further studies are needed to confirm the findings of the present case series.

Titanium Mesh Exposure After Bone Grafting: Treatment Approaches-A Systematic Review

Study Design

A systematic review according to PRISMA statement has been designed to answer the preliminary question: "In titanium mesh exposures, is there a treatment alternative which leads to an increased graft maintenance?" and fill the PICO assessment out.

Objective

To review studies published in the past 20 years (1999-2019) in which mesh exposure has occurred, detecting the suitable approaches to treat exposure allowing the graft maintenance.

Methods

Initial search on PUBMED, SCOPUS, and COCHRANE databases resulted in 777 articles, and hand-searching identified 6 articles. After removing duplicates and unrelated articles, eligibility criteria were applied, and 31 studies were selected (randomized clinical trials, retrospective/prospective clinical trials, and case series).

Results

A total of 677 surgical sites and 225 cases of mesh exposure were identified. Eleven treatments have been identified. Chlorhexidine was the primary approach in 46% of cases, followed by oral hygiene instructions and follow-up with 22.5% of occurrences. In 21% of clinical situations, titanium mesh removal was the treatment of choice, associated with other measures (i.e., antibiotic prescription). There seems to be a consensus in cases of infection. When this complication was associated with tissue dehiscence, the primary treatment was mesh removal. The same does not occur when the site needs to be cleaned for long-term periods.

Conclusion

In 2 decades of use of titanium meshes, the available treatments do not seem to have evolved, and there is not enough data to establish a guideline.

U-shaped Splitting Technique vs Conventional Bone Grafting in Maxillary Facial Undercut for Dental Implants Placement: A Preliminary Randomized Controlled Clinical Trial

AIM

This prospective randomized clinical trial was designed to compare the apical U-shape splitting technique (AUST) combined with guided bone regeneration (GBR) vs GBR alone for horizontal bone augmentation in maxillary labial undercut areas.

MATERIALS AND METHODS

The study included twelve patients with labial undercuts that made their alveolar ridges not able to compass dental implants. They received a total of 14 dental implants in the anterior maxilla where 7 (group I) were placed after AUST with GBR and the other 7 (group II) after the conventional GBR. The clinical and radiographic evaluations were done preoperatively, after surgery, and 6 months later. Facial flap fracture, peri-implant health, ridge width (RW) gain and loss, marginal bone loss (MBL), and implant esthetics were measured. Data were analyzed and compared and for any of the used tests, results were considered statistically significant if p-value ≤ 0.05.

RESULTS

For group I, no fracture of the bone flap happened and the gain in RW was significantly higher at 6 months postoperatively. Marginal bone loss was similar for both groups. The total pink esthetic score was significantly higher in group I vs group II (p = 0.024).

CONCLUSION

Within the limitations of this study, it was concluded that AUST combined with GBR was more effective in RW gain than GBR alone and it provided a merit approach for restoring function and esthetics if labial fenestration was unavoidable during implant placement.

CLINICAL SIGNIFICANCE

Apical U-shape splitting technique for horizontal ridge augmentation is a valuable option for the benefit of patients in clinics who need dental implants and have anterior undercut areas that may lead to fenestration and usually requires onlay bone grafting which is less successful in maintaining the RW.

Bone regeneration using titanium plate stabilization for the treatment of peri-implant bone defects: A retrospective radiologic pilot study

AIM

To 3-dimensional radiographically assess the effect of titanium plate in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in esthetic zone.

MATERIAL AND METHODS

Nineteen patients with buccal peri-implant defects in the maxillary esthetic zone were treated with GBR using xenograft, autogenous bone, and collagen membrane. Subjects were divided into two groups: control (conventional GBR, 10 patients with 16 implants) and test (GBR with an adjunctive titanium plate; nine patients with 15 implants). Cone-beam computed tomography (CBCT) images obtained immediately after and 5-7 months following GBR were used to assess buccal crestal bone level (BBL) and buccal bone thickness (BBT) at different implant levels.

RESULTS

Thirty-one implants in 19 patients were evaluated. Titanium plate exposure occurred in three cases (33.33%) of the test group. After 5-7 months, the mean BBL was located 1.48 ± 0.71 mm coronal to the platform in the test group and 0.90 ± 3.03 mm coronal to the platform in the control group (p = 0.03). The mean over all BBT (BBT-M) was 4.16 ± 0.48 mm in the test group and 2.38 ± 0.97 mm in the control group (p < 0.01). More resorption occurred in the control group than in the test group regarding mean BBL (3.00 ± 3.11 mm vs. 0.78 ± 0.79 mm, respectively; p = 0.04), BBT-M change (1.87 ± 1.59 mm vs. 0.56 ± 0.33 mm, respectively; p = 0.02), and percentage change in BBT-M (40.69 ± 24.01% vs. 11.53 ± 5.86%, respectively; p < 0.01).

CONCLUSION

In the short-term, titanium plate-enhanced GBR maintained ridge dimensions better than conventional GBR did.

Horizontal bone augmentation using two membranes at dehisced implant sites: A randomized clinical study

Background

Placement of dental implant in narrow alveolar ridge is challenging to be treated. GBR procedure is currently most widely used to augment the deficient alveolar ridges and to treat the fenestration and dehiscence around dental implant. Thus, the objectives of the present study were to evaluate as well as compare the clinical performance of collagen membrane and titanium mesh for horizontal bone augmentation at dehisced implant sites.

Methods and material

Total 12 single edentulous implant sites with buccal bone deficiency in 8 subjects were equally divided and treated simultaneously with either of the two membranes and DBBM(Bio-Oss) bone graft. Primary outcome measurements in terms of defect height and defect width were made using calibrated plastic periodontal probe. Re-entry surgery was performed to remeasure augmented site and to remove Ti-mesh at 6th months. Independent paired t-test for the inter-group comparison and student paired t-test for intra-group comparison were performed. The differences were considered to be significant at p ≤ 0.05.

Results

Mean defect fill with respect to height and width was 3.50 ± 0.54 mm (87%) and 2.33 ± 0.51 mm (82%) for collagen membrane and 3.83 ± 0.75 mm (92%) and 2.50 ± 0.54 mm (88%) for Ti-mesh group respectively.

Conclusions

Within the limitation of the study, it was concluded that mean defect height and width after 6 months were statistically significant within the group without significant difference between them, Although defect resolution was better in Ti-mesh.

Clinical Efficacy and Safety of Different Dental Prosthetic Membranes in Guided Bone Regeneration during Dental Implants: A Meta-Analysis

Objective. To evaluate clinical efficacy and safety of absorbable and non-absorbable dental restorative membranes in guided bone regeneration (GBR). Articles concerning absorbable and non-absorbable prosthetic membrane-related studies of GBR were screened from multiple databases. In the end, 526 postoperative patients who met eligibility criteria were screened for the study from eight trials. The results showed that the repair success rate of the experimental group (absorbable dental restorative membrane) was higher than that of the control group (non-absorbable dental restorative membrane) (RR = 1.18, 95% CI [1.11,1.26], and the total physical therapy effect was P < 0.0001, I² = 0%), and the height of bone graft in the experimental group was higher than that in the control group (MD = 0.67, 95% CI [0.11, 1.23]). The thickness of bone graft in the experimental group was higher than that in the control group (MD = 0.43, 95% CI [0.30,0.56], P < 0.00001, I² = 61%), and the adverse events in the experimental group were less than those in the control group (RR = 0.31, 95% CI [0.18, 0.51], P < 0.00001, I² = 13%). Absorbable prosthetic membrane is superior to non-absorbable prosthetic membrane in clinical efficacy and safety.

Effect of Different Membranes on Vertical Bone Regeneration: A Systematic Review and Network Meta-Analysis

This study is aimed at performing a systematic review and a network meta-analysis of the effects of several membranes on vertical bone regeneration and clinical complications in guided bone regeneration (GBR) or guided tissue regeneration (GTR). We compared the effects of the following membranes: high-density polytetrafluoroethylene (d-PTFE), expanded polytetrafluoroethylene (e-PTFE), crosslinked collagen membrane (CCM), noncrosslinked collagen membrane (CM), titanium mesh (TM), titanium mesh plus noncrosslinked (TM + CM), titanium mesh plus crosslinked (TM + CCM), titanium-reinforced d-PTFE, titanium-reinforced e-PTFE, polylactic acid (PLA), polyethylene glycol (PEG), and polylactic acid 910 (PLA910). Using the PICOS principles to help determine inclusion criteria, articles are collected using PubMed, Web of Science, and other databases. Assess the risk of deviation and the quality of evidence using the Cochrane Evaluation Manual, and GRADE. 27 articles were finally included. 19 articles were included in a network meta-analysis with vertical bone increment as an outcome measure. The network meta-analysis includes network diagrams, paired-comparison forest diagrams, funnel diagrams, surface under the cumulative ranking curve (SUCRA) diagrams, and sensitivity analysis diagrams. SUCRA indicated that titanium-reinforced d-PTFE exhibited the highest vertical bone increment effect. Meanwhile, we analyzed the complications of 19 studies and found that soft tissue injury and membrane exposure were the most common complications.

Randomized controlled clinical trial comparing guided bone regeneration of peri-implant defects with soft-type block versus particulate bone substitutes: Six-month results of hard-tissue changes

AIM

To test whether soft-type block bone substitute used for guided bone regeneration (GBR) of peri-implant defects leads to a different dimension of the augmented hard tissue than particulate bone substitute.

MATERIALS AND METHODS

In 40 patients, 40 two-piece dental implants were placed >2 months after tooth extraction. Following random allocation, 20 peri-implant bone dehiscences were grafted with a soft-type block made of synthetic biphasic calcium phosphate (BCP) + collagen and 20 bone dehiscences with particulate BCP. All the sites were covered with a collagen membrane stabilized with titanium pins. Immediately after wound closure and after 6 months, the horizontal dimension (HD) of the augmented hard tissue was measured at the level of implant shoulder using cone beam computed tomography. During re-entry at 6 months, the defect fill was clinically assessed.

RESULTS

At 6 months, the median HD measured 1.15 mm (mean: 1.31 mm) in the soft-block group and 0.93 mm (mean: 1.05 mm) in the particulate group (p = .6). At 6 months, 7.1% of contained defects and 61.9% of non-contained defects showed an incomplete vertical defect fill.

CONCLUSIONS

Soft-type block of BCP + collagen used for GBR of peri-implant defects did not differ from particulate BCP regarding the dimension of the augmented hard tissue after 6 months of healing.

Analysis of a Pure Magnesium Membrane Degradation Process and Its Functionality When Used in a Guided Bone Regeneration Model in Beagle Dogs

For the surgical technique of guided bone regeneration (GBR), the choice of available barrier membranes has until recently not included an option that is mechanically strong, durable, synthetic and resorbable. The most commonly used resorbable membranes are made from collagen, which are restricted in their mechanical strength. The purpose of this study is to evaluate the degradation and regeneration potential of a magnesium membrane compared to a collagen membrane. In eighteen beagle dogs, experimental bone defects were filled with bovine xenograft and covered with either a magnesium membrane or collagen membrane. The health status of the animals was regularly monitored and recorded. Following sacrifice, the hemimandibles were prepared for micro-CT (μ-CT) analysis. Complications during healing were observed in both groups, but ultimately, the regenerative outcome was similar between groups. The μ-CT parameters showed comparable results in both groups in terms of new bone formation at all four time points. In addition, the μ-CT analysis showed that the greatest degradation of the magnesium membranes occurred between 1 and 8 weeks and continued until week 16. The proportion of new bone within the defect site was similar for both treatment groups, indicating the potential for the magnesium membrane to be used as a viable alternative to collagen membranes. Overall, the new magnesium membrane is a functional and safe membrane for the treatment of defects according to the principles of GBR.

Effect of lateral bone augmentation procedures in correcting peri-implant bone dehiscence and fenestration defects: A systematic review and network meta-analysis

Purpose

The aim of the present systematic review was to evaluate the effect of different lateral bone augmentation (LBA) procedures on the complete correction of a peri‐implant bone dehiscence (BD) or fenestration (BF) from implant placement to implant surgical uncovering.

Methods

Electronic (Medline, Scopus, and Cochrane databases) and hand literature searches were performed for studies including at least one treatment arm where any LBA had been applied to correct a BD/BF at implant placement (T0). Studies where BD/BF was left untreated were also retrieved as negative control. Data from 24 selected articles were used to perform a network meta‐analysis. Based on the proportion of nonresolved BD/BF at implant surgical uncovering (T1), a hierarchy of LBA procedures, and was determined. Spontaneous healing (i.e., exposed implant surface covered by a full‐thickness flap; SELF) was also included in the hierarchy. Resorbable membrane + bone graft (RM + BG) was used as reference group. An analysis on the effect of nonhuman (NHBS) vs human (HBS) derived bone substitutes was also performed. NHBS was used as the reference group.

Results

No statistically significant differences were found among treatments for the proportion of nonresolved BD/BF. SELF performed substantially worse compared to RM + BG (OR: 5.78 × 10, CI: 4.83 × 10 – 1.3 × 10⁸⁶). Treatment based on a combination of a graft material and membrane/periosteum appeared to perform slightly better than treatments using graft material or membrane alone. NHBS appeared to perform better than HBS.

SELF had the worst effect among all treatments for both BD/BF height reduction (BDH) and BD/BF width reduction (BDW). Nonresorbable membrane (NRM) and patient's own periosteum (PERI) + BG showed greater increases in buccal bone thickness than RM + BG.

Conclusion

Reconstructive treatment (including use of graft alone, membrane alone, or combinations of grafts and either membrane or patient's own periosteum) of a BD/BF at implant placement favorably and significantly impacts on the probability to obtain complete correction of the BD/BF at implant uncovering when compared to full‐thickness flap repositioning on the BD/BF. When using a bone substitute, a nonhuman derived one may be suggested.

Complications in bone-grafting procedures: Classification and management

Bone-regenerative interventions aiming to restore deficient alveolar ridges, such as the use of block grafts or through the application of guided bone-regeneration principles, have reported positive outcomes in the published scientific literature. These interventions, however, are invasive, and hence, intraoperative and/or postoperative complications may occur. The types of complications and their severity may vary from the exposure of the biomaterial (membrane or graft) to postsurgical infections, neurosensorial disturbances, occurrence of hemorrhage, and pain, etc. The aim of the present narrative review was to search the available scientific evidence concerning the incidence of these complications, their effect on treatment outcomes, their clinical management and, finally, strategies aimed at prevention. Exposure of the barrier membrane or the block graft is the most common complication associated with oral regenerative interventions. To manage these complications, depending on the extent of the exposure and the presence or absence of concomitant infections, therapeutic measures may vary, from the topical application of antiseptics to the removal of the barrier membrane or the block graft. Regardless of their treatment, the occurrence of these complications has been associated with patient selection, with compliant patients (eg, nonsmokers) having a lower reported incidence of complications. Similarly, surgical factors such as correct flap elevation and a tensionless closure are of obvious importance. Finally, to prevent the incidence of complications, it appears prudent to utilize whenever possible less invasive surgical interventions.

[Influencing Hard and Soft Tissue Changes Following Tooth Extraction]

Influencing Hard and Soft Tissue Changes Following Tooth Extraction Abstract. Influencing Hard and Soft Tissue Changes Following Tooth Extraction The loss of a tooth leads to the initiation of resorption processes and thus to the remodeling of the tissues of the alveolar process. At the hard tissue level, this resorption mainly affects the bundle bone at the buccal side of the extracted tooth and occurs most rapidly in the first weeks and months after extraction. Tissue changes occur not only at the level of the hard tissue (bone), but also at the level of the soft tissue. These changes lead to a significant loss of volume, especially at the buccal area of the alveolar ridge. They are responsible for a volume loss of the alveolar ridge contour of up to 50 %.

Customized-3D zirconia barriers for guided bone regeneration (GBR): clinical and histological findings from a proof-of-concept case series

OBJECTIVES

The aim of this case series was to evaluate, clinically and histologically, customized-3D zirconia barriers manufactured for guided bone regeneration (GBR) procedures.

METHODS

Seven healthy consecutive patients with severe bone atrophy (two of them with a bilateral atrophy) were selected for a GBR procedure with a zirconia barrier. In a 3D software (DentalCad, Exocad GmbH, Germany), a virtual bone graft was designed and a shell was designed covering the graft; a standard tessellation language (.STL) file was obtained and milled (M1, Zirkonzahn, Italy) using a 1200 MPa zirconia (Prettau, Zirkonzahn, Italy). Nine GBR surgeries (8 upper-posterior jaw, 1 lower-posterior jaw) were performed using autogenous bone chips mixed with xenograft (SmartBone, IBI-SA, Switzerland / BioOss, Geistlich, Switzerland) covered with a zirconia barrier, fixed by means of screws. After healing, implant sites were prepared with a trephine bur, collecting a bone biopsy, and dental implants were inserted (Neodent, Straumann Group, Switzerland). Specimens were histologically analyzed.

RESULTS

Eight successful surgeries were recorded; one zirconia barrier got exposed after one month of healing but no signs of infection were present till the barrier was removed. In all cases it was possible to insert implants with no additional bone augmentation procedures. Histological evaluations showed the presence of intense deposition of new bone.

CONCLUSIONS

Within the limitations of the present case series, the tested customized-3D zirconia barriers confirmed good clinical and histological performances, and, even in case of premature exposure, did not show signs of infection. Preliminary results suggest they are effective for GBR procedures. Further research is necessary with a larger sample size.

CLINICAL SIGNIFICANCE

The presented barriers could be a viable alternative to titanium-reinforced polytetrafluoroethylene membranes and customized meshes.

Implants sites with concomitant bone regeneration using a resorbable or non-resorbable membrane result in stable marginal bone levels and similar profilometric outcomes over 5 years

OBJECTIVES

To assess clinical and radiographic outcomes as well as the profilometric contour alterations of peri-implant hard and soft tissues around single implants treated with simultaneous guided bone regeneration (GBR) at 5 years.

MATERIALS AND METHODS

Twenty-seven patients presenting with a single tooth gap in the esthetic zone received a two-piece implant. GBR was randomly performed using a resorbable (RES) or a non-resorbable membrane (N-RES) combined with a bone substitute material. Follow-up examinations were performed at baseline (BL = crown insertion), 1 year (FU-1), 3 years (FU-3), and at 5 years (FU-5) including clinical and radiographic parameters as well as profilometric changes. Statistics were performed by means of parametric and nonparametric tests.

RESULTS

At 5 years, 20 out of 27 patients (9 RES, 11 N-RES) were re-examined. Median values for probing depth changed insignificantly between BL and FU-5 in both groups. The median marginal bone levels were located 0.23 mm (0.06; 0.46; RES) and 0.17 mm (0.13;0.28; N-RES) below the implant shoulder at FU-5 (changes over time p < .05). The calculated median profilometric change between BL and FU-5 was -0.28 mm (-0.53;-0.20; RES; p = .016) and -0.24 mm (-0.43;0.08; N-RES; p = .102; intergroup p = .380). The horizontal bone thickness decreased significantly between re-entry and FU-5 for group RES at all measured levels (p < .05) measuring 0.87 mm (0.0; 2.05) at the implant shoulder, whereas the decrease for group N-RES was insignificant (p = .031) with 0 mm (0; 0.84) at the implant shoulder at 5 years.

CONCLUSIONS

Implants sites with concomitant GBR using a resorbable or non-resorbable membrane revealed stable marginal bone levels and clinical outcomes. Profilometric changes were clinically negligible over 5 years. The observed change in hard tissue thickness was partially compensated by an increase in soft tissue thickness.

Immediate implant placement in conjunction with guided bone regeneration and/or connective tissue grafts: an experimental study in canines

Purpose

This study was conducted to assess the effect of hard and/or soft tissue grafting on immediate implants in a preclinical model.

Methods

In 5 mongrel dogs, the distal roots of P2 and P3 were extracted from the maxilla (4 sites in each animal), and immediate implant placement was performed. Each site was randomly assigned to 1 of the following 4 groups: i) gap filling with guided bone regeneration (the GBR group), ii) subepithelial connective tissue grafting (the SCTG group), iii) GBR and SCTG (the GBR/SCTG group), and iv) no further treatment (control). Non-submerged healing was provided for 4 months. Histological and histomorphometric analyses were performed.

Results

Peri-implant tissue height and thickness favored the SCTG group (height of peri-implant mucosa: 1.14 mm; tissue thickness at the implant shoulder and ±1 mm from the shoulder: 1.14 mm, 0.78 mm, and 1.57 mm, respectively; median value) over the other groups. Bone grafting was not effective at the level of the implant shoulder and on the coronal level of the shoulder. In addition, simultaneous soft and hard tissue augmentation (the GBR/SCTG group) led to a less favorable tissue contour compared to GBR or SCTG alone (height of peri-implant mucosa: 3.06 mm; thickness of peri-implant mucosa at the implant shoulder and ±1 mm from the shoulder: 0.72 mm, 0.3 mm, and 1.09 mm, respectively).

Conclusion

SCTG tended to have positive effects on the thickness and height of the peri-implant mucosa in immediate implant placement. However, simultaneous soft and hard tissue augmentation might not allow a satisfactory tissue contour in cases where the relationship between implant position and neighboring bone housing is unfavorable.

Biocompatibility and Physico-Chemical Properties of Highly Porous PLA/HA Scaffolds for Bone Reconstruction

The major problem in bone tissue engineering is the development of scaffolds which can simultaneously meet the requirements of porous structure, as well as have the ability to guide the regeneration of damaged tissue by biological fixation. Composites containing biodegradable matrix and bioactive filler are the new hope in this research field. Herein we employed a simple and facile solvent casting particulate-leaching method for producing polylactide acid/hydroxyapatite (PLA/HA) composites at room temperature. FT-IR analysis confirmed the existence of necessary functional groups associated with the PLA/HA composite, whereas energy-dispersive X-ray (EDX) spectra indicated the uniform distribution of hydroxyapatite particles in the polymer matrix. The beehive-like surface morphology of the composites revealed the presence of macropores, ranged from 300 to 400 μm, whereas the thickness of the pores was noticed to be 1-2 μm. The total porosity of the scaffolds, calculated by hydrostatic weighing, was found to be 79%. The water contact angle of pure PLA was decreased from 83.6 ± 1.91° to 62.4 ± 4.17° due to the addition of hydroxyapatite in the polymer matrix. Thus, the wettability of the polymeric biomaterial could be increased by preparing their composites with hydroxyapatite. The adhesion of multipotent mesenchymal stromal cells over the surface of PLA/HA scaffolds was 3.2 times (p = 0.03) higher than the pure PLA sample. Subcutaneous implantation in mice demonstrated a good tolerance of all tested porous scaffolds and widespread ingrowth of tissue into the implant pores. HA-containing scaffolds showed a less pronounced inflammatory response after two weeks of implantation compared to pure PLA. These observations suggest that PLA/HA composites have enormous potential for hard tissue engineering and restoring maxillofacial defects.

Clinical and histological sequelae of surgical complications in horizontal guided bone regeneration: a systematic review and proposal for management

It is not uncommon to encounter post-surgical complications after horizontal guided bone regeneration (GBR). The primary aim of this review was to evaluate the incidence and types of complications that occur after horizontal GBR and propose management strategies to deal with these clinical situations. A secondary aim was to conduct a histomorphometric review of the wound healing process at sites that experienced post-surgical complications after GBR. A keyword search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for studies published in English from January 2015 to January 2020 was conducted for the primary aim and 23 studies were selected. A second search addressing the secondary aim was conducted, and five studies were included. Site-level analysis showed that the weighted mean incidence proportion of minor wound dehiscence and minor infections occurring at the augmented site was 9.9% [95% CI 6.4, 13.9, P < 0.01] and 1.5% [95% CI 0.4, 3.1, P = 0.21) respectively. Patient-level analysis showed minor and major complications occurring at a weighted mean incidence proportion of 16.1% [95% CI 11.9, 20.8, P = 0.01] and 1.6% [95% CI 0.0, 4.7, P < 0.01] respectively, while neurosensory alterations at the donor site was 7.0% [95% CI 1.3, 15.5, P < 0.01]. Subgroup analysis also revealed that the use of block grafts increased the incidence proportion of minor post-surgical complications, whereas a staged GBR procedure increased the incidence proportion of both minor and major post-surgical complications. Although exposure of the barrier membrane is often associated with less bone regeneration and graft resorption, the type of membrane used (resorbable or non-resorbable) had no statistically significant influence on any post-surgical complication. Histologically, a layer of fibrous connective tissue instead of bone is commonly observed at the interface between the native bone at the recipient site and the regenerated bone in cases with membrane exposure after GBR procedure. Minor wound dehiscence was the highest incidence proportion of post-surgical complications. Methods ranging from daily application of antiseptics, use of systemic antimicrobials, regular reviews, and total removal of the non-integrated biomaterials are commonly prescribed to manage these post-surgical complications in attempt to minimise the loss of tissue at the surgical site.

Collagen membranes of dermal and pericardial origin-In vivo evolvement of vascularization over time

Aim of the study was to compare the evolvement of vascularization over time of collagen membranes (CMs) of dermal and pericardial origin in an in vivo animal study. Twenty-eight mice underwent implantation of three commercially available CM derived from porcine dermis (homogenous structure: CM1 (Control 1) and bilayer structure: CM2 [Control 2]), from porcine pericardium (CM3; Test 1) as well as CM3 sprayed with silica-enhanced nanostructured hydroxyapatite (CM4, Test 2). After 3, 6, 9, and 12 days, intravital fluorescence microscopy was conducted for determination of capillary diameter, density, flow, and length. At Day 12, samples were examined immunohistologically for expression of fibroblast growth factor receptor 4 (FGFR4), CD11b, CD68, αSMA, and CD34. In all CM, intravital fluorescence microscopy over time showed increasing values for all parameters with the highest levels in CM4 and the lowest values in CM1. Significant lower amounts of FGFR4, CD11b, and CD68 were detected in CM4 when compared to CM2 (p < .05). In contrast to CM3, lower values of αSMA and higher numbers of CD34 positive-marked vessels were observed in CM4 (p < .05). In conclusion, dermal bilayer as well as pericardial CM seem to have a higher vascularization rate than dermal homogenous CM. Additional coating of pericardial CM with a silica-enhanced hydroxyapatite increases the speed of vascularization as well as biological remodeling processes.

Selection of Collagen Membranes for Bone Regeneration: A Literature Review

Several treatment modalities have been proposed to regenerate bone, including guided bone regeneration (GBR) where barrier membranes play an important role by isolating soft tissue and allowing bone to grow. Not all membranes biologically behave the same way, as they differ from their origin and structure, with reflections on their mechanical properties and on their clinical performance. Collagen membranes have been widely used in medicine and dentistry, because of their high biocompatibility and capability of promoting wound healing. Recently, collagen membranes have been applied in guided bone regeneration with comparable outcomes to non-resorbable membranes. Aim of this work is to provide a review on the main features, application, outcomes, and clinical employment of the different types of collagen membranes. Comparisons with non-resorbable membranes are clarified, characteristics of cross-linked collagen versus native collagen, use of different grafting materials and need for membrane fixation are explored in order to gain awareness of the indications and limits and to be able to choose the right membrane required by the clinical condition.

Efficacy of lateral bone augmentation performed simultaneously with dental implant placement: A systematic review and meta-analysis

OBJECTIVES

To analyse the evidence regarding the efficacy of lateral bone augmentation procedures in terms of defect resolution in cases of horizontal ridge deficiencies after implant placement.

MATERIALS AND METHODS

Included studies met the following inclusion criteria: randomized controlled trials (RCTs) or controlled clinical trials (CCTs), re-entry procedure to assess defect resolution, minimum of 10 patients (5 per group). Meta-analyses were performed whenever possible, including subgroup analysis based on membranes and grafting materials.

RESULTS

Twenty-eight publications (20 short-term, 8 follow-up studies) were included. The most often used type of intervention was a xenogeneic particulated grafting material (XE) and a resorbable collagen membrane (CM). The mean defect height at baseline amounted to 5.1 mm (range 2.4-7.8) and decreased to a mean of 0.9 mm (range 0.2-2.2) at re-entry, and the mean defect resolution was 81.3% (range 56.4%-97.1%). Defect height reduction was not significantly different using CM+XE as control treatment compared to the combined data of the respective test groups [n = 11; weighted mean difference (WMD) = -0.006 mm; 95% CI, -0.61, 0.60; p = 0.985]. The absence of any lateral bone augmentation was less favourable than the conjunction of a membrane and a bone grafting material (n = 1; MD = -1.96 mm; 95% CI, -3.48, -0.44; p = 0.011). The lack of a grafting material was less favourable than the conjunction of grafting material and membrane (n = 1; MD = -2.44 mm; 95% CI, -4.53, -0.35; p = 0.022), and the addition of a membrane compared to a grafting material alone was more favourable (n = 3; WMD = 0.97 mm; 95% CI, 0.31, 1.64; p = 0.004).

CONCLUSIONS

Lateral bone augmentation is a successful treatment modality. For optimal defect height reduction, a barrier membrane and a grafting material should be combined.

A standardized rat burr hole defect model to study maxillofacial bone regeneration

With high incidence rate and unique regeneration features, maxillofacial burr hole bone defects require a specially designed bone defect animal model for the evaluation of related bone regenerative approaches. Although some burr hole defect models have been developed in long bones or calvarial bones, the mandible has unique tissue development origins and regenerative environments. This suggests that the defect model should be prepared in the maxillofacial bone area. After dissecting the anatomic structures of rat mandibles, we found that creating defects in the anterior tooth area avoided damaging important organs and improved animal welfare. Furthermore, the available bone volume at the anterior tooth area was superior to that of the posterior tooth and ascending ramus areas. We then managed to standardize the model by controlling the age, weight and gender of the animal, creating standardized measurement instruments and reducing the variations derived from various operators. We also succeeded in deterring the self-rehabilitation of the proposed model by increasing the defect size. The 6 × 2 mm and 8 × 2 mm defects were found to meet the requirements of bone regenerative studies. This study provided a step-by-step standardized burr hole bone defect model with minimal tissue damage in small animals. The evaluations resulting from this model testify to the in vitro outcomes of the proposed regenerative approaches and provide preliminary screening data for further large animal and clinical trials. Therefore, the inclusion of this model may optimize the evaluation systems for maxillofacial burr hole bone defect regenerative approaches. STATEMENT OF SIGNIFICANCE: Unremitting effort has been devoted to the development of bone regenerative materials to restore maxillofacial burr hole bone defects because of their high clinical incidence rate. In the development of these biomaterials, in vivo testing in small animals is necessary to evaluate the effects of candidate biomaterials. However, little has been done to develop such defect models in small animals. In this study, we developed a standardized rat mandible burr hole bone defect model with minimal injury to the animals. A detailed description and supplementary video were provided to guide the preparation. The development of this model optimizes the maxillofacial bone regenerative approach evaluation system.

Influence of wound closure on volume stability with the application of different GBR materials: an in vitro cone-beam computed tomographic study

PURPOSE

To assess the influence of using different combinations of guided bone regeneration (GBR) materials on volume changes after wound closure at peri-implant dehiscence defects.

METHODS

In 5 pig mandibles, standardized bone defects were created and implants were centrally placed. The defects were augmented using different combinations of GBR materials: xenogeneic granulate and collagen membrane (group 1, n=10), xenogeneic granulate and alloplastic membrane (group 2, n=10), alloplastic granulates and alloplastic membrane (group 3, n=10). The horizontal thickness was assessed using cone-beam computed tomography before and after suturing. Measurements were performed at the implant shoulder (HT0) and at 1 mm (HT1) and 2 mm (HT2) below. The data were statistically analysed using the Wilcoxon signed-rank test to evaluate within-group differences. Bonferroni correction was applied when calculating statistical significance between the groups.

RESULTS

The mean horizontal thickness before suturing was 2.55±0.53 mm (group 1), 1.94±0.56 mm (group 2), and 2.49±0.73 mm (group 3). Post-suturing, the values were 1.47±0.31 mm (group 1), 1.77±0.27 mm (group 2), and 2.00±0.48 mm (group 3). All groups demonstrated a loss of horizontal dimension. Intragroup changes exhibited significant differences in group 1 (P<0.001) and group 3 (P<0.01). Intergroup comparisons revealed statistically significant differences of the relative changes between groups 1 and 2 (P=0.033) and groups 1 and 3 (P=0.015).

CONCLUSIONS

Volume change after wound closure was minimized by using an alloplastic membrane. The stability of the augmented horizontal thickness was most ensured by using this type of membrane irrespective of the bone substitute material used for membrane support.

Apical U-shape splitting technique for undercut areas of the anterior alveolar ridge: a prospective non-randomized controlled study

The aim of this study was to investigate a novel apical U-shape splitting technique for horizontal bone augmentation in undercut areas and to compare its efficacy with that of guided bone regeneration (GBR). This was a prospective non-randomized controlled clinical trial. A total of 36 patients, who presented with a labial undercut that was not able to house a normally inclined implant, underwent the new technique or GBR. Radiographic and clinical data were obtained preoperatively, immediately after surgery, and 12 months after surgery. Pairwise comparisons of changes in ridge width gain, marginal bone loss, and pink aesthetic score were performed; correlations with pristine ridge morphology were investigated. The results showed similar marginal bone loss in the two groups. The overall ridge width gains in the new technique group (2.56±1.92mm) and GBR group (0.73±1.21mm) differed significantly (P<0.05). The pink aesthetic score was higher for the new technique group (11.75±1.22) than for the GBR group (9.25±1.86) (P<0.01). The morphology of the concavity had different impacts on regeneration in the two groups. The apical U-shape splitting technique, as a safe and effective alternative to GBR, provided a significant increase in bone volume gain where labial fenestration was inevitable during implant placement.

A new modified bone grafting technique for periodontally accelerated osteogenic orthodontics

The aim of this study was to introduce an improved surgical technique using a pouch design and tension-free wound closure for periodontally accelerated osteogenic orthodontics (PAOO) in the anterior alveolar region of the mandible.Patients with bone dehiscence and fenestrations on the buccal surfaces of the anterior mandible region underwent the modified PAOO technique (using a pouch design and tension-free closure). Postoperative symptoms were evaluated at 1 and 2 weeks intervals following the procedure. Probing depth (PD), gingival recession depth (GRD), and clinical attachment level (CAL) were assessed at the gingival recession sites at baseline, postoperative 6 and 12 months. Cone-beam computerized tomography (CBCT) was used for quantitative radiographic analyses at baseline, 1 week and 12 months after bone-augmentation procedure.The sample was composed of a total of 12 patients (2 males and 10 females; mean age, 21.9 years) with 72 teeth showing dehiscence/fenestrations and 17 sites presenting with gingival recessions. Clinical evaluations revealed a statistically significant reduction in swelling, pain, and clinical appearance from postoperative week 1 to week 2 (P < .05). Moreover, gingival recession sites exhibited a significant reduction in the GRD and an increase in CAL after surgery with mean root coverage of 69.8% at the end of observation period (P < .01). Both alveolar bone height and width increased after surgery (P < .01) and decreased during the 12-month follow-up (P < .01). However, compared with the baseline records, there was still a significant increase in alveolar bone volume (P < .01).This modified PAOO technique may have advantages in terms of soft and hard tissue augmentation, facilitating extensive bone augmentation and allowing the simultaneous correction of vertical and horizontal defects in the labial aspect of the mandibular anterior area.

Bone Regeneration of Peri-Implant Defects Using a Collagen Membrane as a Carrier for Recombinant Human Bone Morphogenetic Protein-2

This study is designed to determine the effect of collagen membrane (CM) soaked with bone morphogenetic protein-2 (rhBMP-2) for the treatment of peri-implant dehiscence defects. Material and Methods. Three treatment groups were allocated at each defect in 5 dogs: (i) collagenated synthetic bone (OC) and CM soaked with rhBMP-2 (BMP group), (ii) OC and CM soaked with saline (nonBMP group), and (iii) no further treatment (control group). Titanium pins were used to stabilize the membranes in two dogs. Radiographic and histomorphometric analyses were performed 4 weeks later. Results. The median augmented volumes were 4.27 mm³, 6.24 mm³, and 2.75 mm³ in the BMP, nonBMP, and control groups, respectively; the corresponding median first bone-to-implant contact (fBIC) distances were 3.25 mm, 3.08 mm, and 2.56 mm (P > 0.05). The placement of pins (with the BMP and nonBMP groups pooled) significantly improved bone regeneration: the augmented volumes were 17.60 mm³ with pins and 3.68 mm³ without pins (P = 0.024), with corresponding fBIC distances of 2.25 mm and 3.31 mm, respectively (P < 0.001). Conclusions. The addition of rhBMP-2 to CM failed to improve bone regeneration of peri-implant dehiscence defects compared to using an unsoaked CM after 4 weeks. However, the stabilization of CMs using pins positively influenced the outcomes.

Volumetric changes following ridge preservation or spontaneous healing and early implant placement with simultaneous guided bone regeneration

AIM

To assess volumetric and linear changes following ridge preservation (RP) or spontaneous healing plus early implant placement with or without simultaneous guided bone regeneration (GBR).

MATERIALS AND METHODS

In eight adult beagle dogs, the mesial roots of the mandibular P3, P4 and M1 were extracted. Sites were randomized to either ridge preservation (RP) or spontaneous healing (SH). Four weeks later dental implants were placed either with (RP2) or without removing non-integrated DBBM (RP1). In RP2 and SH sites, GBR was applied using a demineralized bovine bone mineral and a resorbable membrane. Impressions were taken postextraction (SH)/postridge preservation (RP1; RP2), before and after implant placement and after healing of 4 and 12 weeks. Casts were digitized to allow for superimposition and measurement of contour alterations.

RESULTS

Median ridge width reduction from postextraction (SH)/postridge preservation (RP1;RP2) to implant placement ranged from -13.9% (SH) to -19.7% (RP) (p > .05), whereas from implant placement to sacrifice, it was statistically significantly lower in group RP1 (-5.5%) compared to group SH (-23.4%; p = .0013) and group RP2 (-22.1%; p = .0026). Encompassing the entire study period, median ridge width changes ranged between -17.8% (SH), -24.8% (RP2) and -32.5% (RP1) (p > .05).

CONCLUSIONS

Irrespective of the treatment modality and the healing period, part of the ridge contour was lost. Early implant placement after ridge preservation without additional GBR resulted in a more stable ridge contour after implant placement compared to controls.

Contour changes after guided bone regeneration of large non-contained mandibular buccal bone defects using deproteinized bovine bone mineral and a porcine-derived collagen membrane: an experimental in vivo investigation

OBJECTIVE

The objective of this study was to evaluate soft tissue contour changes after three different regenerative therapies in chronic ridge defects.

MATERIAL AND METHODS

Buccal bone defects were created in the mandible of nine beagle dogs. Augmentation procedures were performed 3 months later using a bone replacement graft (BRG), resorbable collagen membrane (MBG), or a combination of both procedures (CBG). Silicone impressions were taken before tooth extraction (T1), before the augmentation procedure (T2), and 3 months after the regenerative surgeries (T3). Casts were optically scanned and stereolithography files were superimposed to analyze the horizontal changes in ridge contours.

RESULTS

After defect creation, most part of the horizontal changes occurred 4 and 6 mm below the gingival margin. In the mesial defect (D1) at T3, the mean horizontal gain in MBG amounted to 0.47 ± 0.34 mm, 0.79 ± 0.67 mm in the BRG, and 0.87 ± 0.69 mm for the CBG. In the middle defect (D2), the mean changes for the MBG were 0.11 ± 0.31, 1.01 ± 0.91 for the BRG, and 0.98 ± 0.49 for the CBG. The mean changes in the distal defect (D3) amounted to 0.24 ± 0.72 for the MBG, 1.04 ± 0.92 for the BRG, and 0.86 ± 0.56 for the CBG. The differences reached significance in all defects for the comparison MBG-BRG and MBG-CBG, while similar parameters were observed for the comparison BRG-CBG.

CONCLUSION

BRG and CBG were equally effective and superior to MBG in increasing the horizontal tissue contours. The augmentation seldom reached the values before extraction.

CLINICAL RELEVANCE

Scaffolding materials are needed for contour augmentation when using resorbable collagen membranes.