The influence of wound closure on graft stability: An in vitro comparison of different bone grafting techniques for the treatment of one-wall horizontal bone defects

Immediate versus early implant placement for single tooth replacement in the aesthetic area: A systematic review and meta-analysis

OBJECTIVES

To compare immediate implant placement (IIP) with early implant placement (EIP) for single tooth replacement in the aesthetic area in terms of aesthetic, clinical, and patient-reported outcomes.

MATERIALS AND METHODS

Two independent reviewers conducted an electronic literature search in PubMed, Web of Science, Embase, and Cochrane databases as well as a manual search to identify eligible clinical studies up to February 2023. Randomized Controlled Trials (RCTs) comparing IIP with EIP were included for a qualitative and quantitative analysis. The primary outcome was vertical midfacial soft tissue change. Secondary outcomes were horizontal midfacial soft tissue change, vertical papillary change, pink esthetic score (PES), implant survival, buccal bone thickness, marginal bone level change, patient discomfort, chair time, and patient satisfaction.

RESULTS

Out of 1185 records, 6 RCTs were selected, reporting on 222 patients who received 222 single implants (IIP: 112 implants in 112 patients; EIP: 110 implants in 110 patients) in the anterior maxilla or mandible. Patients had a mean age ranging from 35.6 to 52.6 years and were followed between 8 and 24 months. Two RCTs showed some concerns, and four showed a high risk of bias. Four studies could be included in a meta-analysis on the primary outcome and three only considered cases with an intact buccal bone wall. Meta-analysis failed to demonstrate a significant difference in terms of vertical midfacial soft tissue change between IIP and EIP (mean difference: 0.31 mm, 95% CI [-0.23; 0.86], p = .260; I2 = 83%, p < .001). No significant differences were found for PES (standardized mean difference: 0.92, 95% CI [-0.23; 2.07], p = .120; I2 = 89%, p < .001), implant survival (RR: 0.98, 95% CI [0.93, 1.03], p = .480; I2 = 0%, p = .980), and marginal bone level change (mean difference: 0.03 mm, 95% CI [-0.12, 0.17], p = .700; I2 = 0%, p = .470). Insufficient data were available for meta-analyses of other secondary outcomes.

CONCLUSION

In low-risk patients with an intact buccal bone wall, there seems to be no difference between IIP and EIP in terms of aesthetic and clinical outcomes. The strength of this conclusion is rated as low since studies showed an unclear or high risk of bias. In addition, state-of-the-art therapy was only delivered in a minority of studies. Future RCTs should also provide data on patient-reported outcomes since these have been underreported.

Lateral bone augmentation with a composite graft covered with a stretched and pinned collagen membrane: A retrospective case series using cone-beam computed tomography

AIMS

(1) To assess the effectiveness of the Sausage Technique™ when applied for lateral bone augmentation by multiple experienced clinicians; (2) To identify risk indicators for a poor outcome and to assess the need for adjunctive surgery.

MATERIALS AND METHODS

All patients who had been treated with the Sausage Technique™ for lateral bone augmentation by three experienced surgeons between January 2019 and December 2021 were included in a retrospective case series. The Sausage Technique™ technique includes the use of autogenous bone chips and deproteinized bovine bone mineral (1:1 ratio), covered with a stretched and pinned collagen membrane. The increase in alveolar width between the pre-operative situation and 9 months was assessed at different levels on superimposed cone-beam CT scans.

RESULTS

Twenty-five augmentations performed in 25 patients (17 males, 8 females, mean age 51 years) were available for evaluation. Mean alveolar width increased from 4.35 to 7.43 mm at 3 mm below the crest. The mean increase of 3.08 mm (95% CI 2.10-4.06; p < 0.001) was significant. The outcome of non-containing single implant sites was significantly worse than the outcome of other sites (MD 2.67 mm; p = 0.008). The need for regrafting was 4% and the need for soft tissue augmentation was 48%. Twenty percent of the patients needed soft tissue augmentation due to a lack of keratinized mucosa width, and 32% due to a lack of buccal convexity. The former was mainly needed at multiple implant sites, whereas the latter was mainly required at single implant sites. All implant survived and remained healthy until the final follow-up.

CONCLUSION

The Sausage Technique™ is an effective bone augmentation technique. Non-containing single implant sites were associated with a poor outcome and adjunctive soft tissue augmentation was needed in about half of the patients.

Anti-Wound Dehiscence and Antibacterial Dressing with Highly Efficient Self-Healing Feature for Guided Bone Regeneration Wound Closure

Guided bone regeneration (GBR) is a well-established technique for preserving and enhancing alveolar ridge structures. Success in GBR relies on fulfilling the Primary wound closure, Angiogenesis, Space maintenance, and Stability (PASS) principles. Conventional methods, involving titanium meshes and sutures, have drawbacks, including the need for secondary removal and customization challenges. To address these issues, an innovative multifunctional GBR dressing (MGD) based on self-healing elastomer (PUIDS) is introduced. MGD provides sutureless wound closure, prevents food particle accumulation, and maintains a stable environment for bone growth. It offers biocompatibility, bactericidal properties, and effectiveness in an oral GBR model. In summary, MGD provides a reliable, stable osteogenic environment for GBR, aligning with PASS principles and promoting superior post-surgery bone regeneration.

Full block or split block?-Comparison of two different autogenous block grafting techniques for alveolar ridge reconstruction

OBJECTIVE

To evaluate radiographic bone gain after alveolar ridge augmentation with two different designs of autogenous block graft harvested from the mandible.

MATERIALS AND METHODS

Alveolar ridge defects were evaluated by preoperative cone beam computed tomography (CBCT) and grafted in a staged approach using intraoral block grafts. The ridge augmentation was either performed using the full-block technique (group 1) or the split-block technique (cortical plate with autogenous bone chips) (group 2). After 4 months of bone healing, a further CBCT scan was performed before implant placement. Horizontal and vertical bone gain were measured.

RESULTS

In this retrospective study, 91 patients were grafted with block grafts (36 patients with full-block grafts; 55 patients with split-block grafts) resulting in 171 block grafts in total. The mean horizontal bone gain was 3.37 ± 0.71 mm in group 1 and 5.79 ± 2.20 mm in group 2. A linear mixed-effect model also showed a statistically significant group difference (p < 0.001, estimate: 3.455, 95% CI: [2.082-4.829]). The mean vertical bone gain was 2.85 ± 0.73 mm in group 1 and 7.60 ± 1.87 mm in group 2. A linear mixed-effect model also showed a statistically significant group difference (p: 0.029, estimate: 3.126, 95% CI: [0.718-5.557]). Mean marginal bone level was 0.33 ± 0.37 mm (group 1) and 0.17 ± 0.29 mm (group 2).

CONCLUSION

The split-block technique resulted in a greater bone gain than the full-block technique. This effect was observed in both the vertical and the horizontal dimensions.

Radiographic evaluation of alveolar ridge preservation using a chitosan/polyvinyl alcohol nanofibrous matrix: A randomized clinical study

The objective of this randomized clinical trial (RCT) was to assess the effectiveness of electrospun chitosan/polyvinyl alcohol (CS/PVA) nanofibrous scaffolds in preserving the alveolar ridge and enhancing bone remodeling following tooth extraction when compared to a control group. In this split RCT, 24 human alveolar sockets were randomly assigned to two groups, with 12 sockets receiving CS/PVA nanofibrous scaffold grafts (test group) and 12 left to heal by secondary intention as the control group. Cone-beam computed tomography (CBCT) was performed at two different time points: immediately after extraction (T0) and 4 months post-extraction (T4). After 4 months, linear vertical and horizontal radiographic changes and bone density of extraction sockets were assessed in both the test and control groups. The RCT included 12 patients (4 male and 8 female) with a mean age of 24 ± 3.37 years. The test group had a significantly lower mean vertical resorption vs the control group, with a mean difference of 1.1 mm (P < 0.05). Similarly, the control group's mean horizontal bone resorption was -2.01 ± 1.04 mm, while the test group had a significantly lower mean of -0.69 ± 0.41 mm, resulting in a mean difference of 1.35 mm (P < 0.05). Furthermore, the study group exhibited a significant increase in bone density (722.03 ± 131.17 HU) after 4 months compared to the control group (448.73 ± 93.23 HU). In conclusion, we demonstrated within the limitations of this study that CS/PVA nanofibrous scaffold significantly limited alveolar bone resorption horizontally and vertically and enhanced bone density in alveolar sockets after 4 months when compared to results in the control group (TCTR20230526005).

Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Clinical and Tomographic Study

Horizontal bone augmentation is a common surgical procedure used in implant therapy to achieve adequate bone volume to permit dental implant placement. However, most current techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate a new device that will permit bidirectional bone augmentation. Ten patients of both sexes (7 women and 3 men), with ages ranging from 29 to 62 years, who needed a bidirectional horizontal bone augmentation in maxilla were separated in accordance with the horizontal alveolar change (HAC) classification published by Pelegrine et al (2018). The patients classified as HAC 3 (ie, containing remaining cancellous bone at the recipient bed) received the Barbell device with xenogeneic biomaterial and a collagen membrane, whereas HAC 4 patients (ie, with no remaining cancellous bone at the recipient bed) received the Barbell device with a mixture of autogenous bone chips and xenogeneic biomaterial covered by a collagen membrane. For each patient, two computerized tomography scans were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness (T0) in the studied sites were 3.25 ± 0.35 in HAC 3 and 1.98 ± 0.5 in HAC 4 patients. The mean bone thickness achieved after 6 months was 7.70 ± 0.89 mm and 8.62 ± 0.89 in HAC 3 and 4, respectively. All grafted sites were able to receive dental implants in adequate prosthetic positions. Based on these results, the use of this novel device permits bidirectional horizontal bone augmentation.

Band-Aid-Like Self-Fixed Barrier Membranes Enable Superior Bone Augmentation

In guided bone regeneration surgery, a barrier membrane is usually used to inhibit soft tissue from interfering with osteogenesis. However, current barrier membranes usually fail to resist the impact of external forces on bone-augmented region, thus causing severe displacement of membranes and their underlying bone graft materials, eventually leading to unsatisfied bone augmentation. Herein, a new class of local double-layered adhesive barrier membranes (ABMs) is developed to successfully immobilize bone graft materials. The air-dried adhesive hydrogel layers with suction-adhesion properties enable ABMs to firmly adhere to the wet bone surface through a "stick-and-use" band-aid-like strategy and effectively prevent the displacement of membranes and the leakage of bone grafts in uncontained bone defect treatment. Furthermore, the strategy is versatile for preparing diverse adhesive barrier membranes and immobilizing different bone graft materials for various surgical regions. By establishing such a continuous barrier for the bone graft material, this strategy may open a novel avenue for designing the next-generation barrier membranes.

Immunohistochemical comparison of lateral bone augmentation using a synthetic TiO2 block or a xenogeneic graft in chronic alveolar defects

OBJECTIVES

To evaluate osteogenic markers and alveolar ridge profile changes in guided bone regeneration (GBR) of chronic noncontained bone defects using a nonresorbable TiO₂ block.

MATERIALS AND METHODS

Three buccal bone defects were created in each hemimandible of eight beagle dogs and allowed to heal for 8 weeks before GBR. Treatment was assigned by block randomization: TiO₂ block: TiO₂ -scaffold and a collagen membrane, DBBM particulates: Deproteinized bovine bone mineral (DBBM) and a collagen membrane, Empty control: Only collagen membrane. Bone regeneration was assessed on two different healing timepoints: early (4 weeks) and late healing (12 weeks) using several immunohistochemistry markers including alpha-smooth muscle actin (α-SMA), osteopontin, osteocalcin, tartrate-resistant acid phosphatase, and collagen type I. Histomorphometry was performed on Movat Pentachrome-stained and Von Kossa/Van Gieson-stained sections. Stereolithographic (STL) models were used to compare alveolar profile changes.

RESULTS

The percentage of α-SMA and osteopontin increased in TiO₂ group after 12 weeks of healing at the bone-scaffold interface, while collagen type I increased in the empty control group. In the defect area, α-SMA decreased in the empty control group, while collagen type I increased in the DBBM group. All groups maintained alveolar profile from 4 to 12 weeks, but TiO₂ group demonstrated the widest soft tissue contour profile.

CONCLUSIONS

The present findings suggested contact osteogenesis when GBR is performed with a TiO₂ block or DBBM particulates. The increase in osteopontin indicated a potential for bone formation beyond 12 weeks. The alveolar profile data indicated a sustained lateral increase in lateral bone augmentation using a TiO₂ block and a collagen membrane, as compared with DBBM and a collagen membrane or a collagen membrane alone.

The allogeneic shell technique for alveolar ridge augmentation: a multicenter case series and experiences of more than 300 cases

PURPOSE

Allogeneic cortical bone plates (CP) might be used for alveolar ridge augmentation as an alternative to autogenous grafts (AG) and bone substitutes (BS). We report about a multicenter case series and our experiences of more than 300 cases using CP and the shell technique for reconstruction of the alveolar process to illustrate surgical key steps, variations, and complication management.

METHODS

Different types of alveolar ridge defects were augmented using the shell technique via CP. The space between the CP and the alveolar bone was filled with either autogenous or allogeneic granules (AUG, ALG) or a mixture of both. Implants were placed after 4-6 months. Microscopic and histological assessments were performed. In addition, space filling using AUG, ALG and bovine BS was discussed.

RESULTS

Scanning electron microscopy demonstrated the compact cortical structure of CP and the porous structure of ALG allowing micro-vessel ingrowth and bone remodeling. Histological assessment demonstrated sufficient bone remodeling and graft resorption after 4-6 months. In total, 372 CP cases and 656 implants were included to data analysis. The mean follow-up period was about 3.5 years. Four implants failed, while all implant failures were caused by peri-implantitis. Next, 30 CP complications were seen, while in 26 CP complications implant placement was possible. CP rehydration, stable positioning by adjusting screws, smoothing of sharp edges, and a tension-free wound closure were identified as relevant success factors. Space filling using ALG and a mixture of AUG/ALG resulted in sufficient bone remodeling, graft resorption and stability of the augmented bone.

CONCLUSIONS

CP and the shell technique is appropriate for alveolar ridge augmentation with adequate bone remodeling and low complication rates. Allografts can prevent donor site morbidity and therefore may decrease discomfort for the patient.

Immediate implant placement utilizing vestibular socket therapy versus early implant placement with contour augmentation for rehabilitation of compromised extraction sockets in the esthetic zone: A randomized controlled clinical trial

OBJECTIVE

The present randomized controlled trial compares for the first time the vestibular socket therapy (VST) to the contour augmentation technique in the management of compromised fresh extraction sockets in the maxillary esthetic zone, regarding mid-facial soft tissue changes (primary outcome), mesial and distal papillae dimensions, horizontal soft tissue changes and labial bone plate thickness at apical, middle and coronal levels (secondary outcomes) over 1-year.

MATERIALS AND METHODS

Forty participants with single nonrestorable maxillary teeth in the esthetic zone were randomized into two groups; VST (test; n = 20) utilizing vestibular access for guided bone regeneration (GBR) with immediate implant placement, or contour augmentation (control; n = 20) undergoing an initial healing period followed by implant placement with GBR through a conventional access flap.

RESULTS

All implants were successfully osseo-integrated, except for one implant in the test group. VST showed significantly less mid-facial soft tissue changes of -0.53 ± 1.17 mm versus -1.87 ± 0.69 mm in the control group (p < 0.001). Similarly, changes in mesial papilla (test = -0.64 ± 0.95 mm, control = -1.20 ± 0.81 mm), distal papilla (test = -0.56 ± 1.17 mm, control = -1.26 ± 0.63 mm), horizontal soft-tissue (test = -0.82 ± 0.95 mm, control = -1.84 ± 0.88 mm; p < 0.05) were significantly less in VST. Intra-group comparisons demonstrated a significant increase in labial bone thickness, with no differences between groups. Regression analysis revealed a significant correlation between VST as well as increased coronal bone thickness with the reduction in mid-facial soft-tissue changes.

CONCLUSION

The VST showed less soft-tissue changes and could represent an innovative technique for implant placement in the maxillary esthetic zone. Both techniques showed a high implant survival rate and increased bone thickness after 12 months.

Implant stability of narrow diameter implants in hyperglycemic patients-A 3-month case-control study

OBJECTIVES

The aim of this prospective case-control study was to compare the development of implant stability quotients of narrow diameter implants in patients with type 2 diabetes mellitus (T2DM) and healthy individuals within the first 3 months after implant insertion.

METHODS

Sixteen patients with T2DM (HbA1C > 6.5%) as test group and 16 nondiabetic patients (HbA1C < 5.9%) as the control group were evaluated. All patients received narrow-diameter tissue level implants in an edentulous area posterior to the canine. The implant stability was measured by means of resonance frequency analysis after 3 days, 7 days, 4 weeks, and 3 months postplacement. Statistical analysis of intergroup differences and correlation to HbA1c values and treated jaw was performed in PRISM 8.

RESULTS

The means for implant stability quotients showed a significant increase between Day 3 and 3-month assessment in both groups. No significant differences between study groups and no correlation of implant stability to HbA1c were found.

CONCLUSION

The present study shows encouraging clinical outcomes for narrow-diameter implants inserted in the posterior zone in patients with uncontrolled T2DM.

Surgical guides for guided bone augmentation: an in vitro study

AIM

To validate in vitro the accuracy of a novel method for bone augmentation of horizontal alveolar bone defects with the help of a surgical guide.

MATERIAL AND METHODS

Six cone-beam computed tomography scans of patients requiring horizontal bone augmentation were segmented and 3D printed. Two surgeons performed the bone augmentation surgery twice for each case on 3D printed models, using either a conventional or guided protocol. Each surgeon virtually planned the desired graft shape beforehand. The resulting grafts were compared linearly and volumetrically to the plan; graft density and surgical time were also analyzed.

RESULTS

There was significantly less graft volume outside the planned volume with the guided protocol (36.8% ± 14.1 vs 19.6% ± 12.3, p < 0.01). The use of a guide increased graft accuracy at several measurement points, resulting in less overfill when using the guided protocol (1.7 ± 1.7 mm at the most coronal point, 0.2 mm ± 1.4 at 25%, 0.0 mm ± 0.9 at 50%, 0.1 mm ± 1.1 at 75%, 0.4 mm ± 1.4 apically). Graft thickness was increased 1 mm coronally from the planned graft (2.8 mm ± 2.3 vs 1.8 mm ± 2.2, p = 0.04). Surgical time increased significantly when using a guide (a difference of 2m26s).

CONCLUSION

The technique, tested here in vitro, allows surgeons to improve the accuracy of the resulting graft shape, to better compact material in the coronal portion of the graft, and to reduce the amount of graft material placed outside the planned volume.

Horizontal Augmentation of Chronic Mandibular Defects by the Guided Bone Regeneration Approach: A Randomized Study in Dogs

Various biomaterial combinations have been studied focusing on their ability to stabilize blood clots and maintain space under soft tissue to support new bone formation. A popular combination is Deproteinized Bovine Bone Mineral (DBBM) placed with a native collagen membrane (NCM) tacked to native bone. In this study, we compared the outcome of this treatment option to those achieved with three different graft/membrane combinations with respect to total newly occupied area and the mineralized compound inside. After bi-lateral extraction of two mandibular premolars in five adult beagles L-shaped alveolar defects were created. A total of 20 defects healed for 6 weeks resulting in chronic type bone defects. At baseline, four options were randomly allocated to five defects each: a. DBBM + NCM with a four-pin fixation across the ridge; b. DBBM + RCLC (ribose cross-linked collagen membrane); c. DBBM + NPPM (native porcine pericardium membrane); and d. Ca-sulfate (CS) + RCLC membrane. Membranes in b/c/d were not fixed; complete tensionless wound closure was achieved by CAF. Termination after 3 months and sampling followed, and non-decalcified processing and toluidine blue staining were applied. Microscopic images obtained at standardized magnification were histomorphometrically assessed by ImageJ software (NIH). An ANOVA post hoc test was applied; histomorphometric data are presented in this paper as medians and interquartile ranges (IRs). All sites healed uneventfully, all sites were sampled and block separation followed before Technovit embedding. Two central sections per block for each group were included. Two of five specimen were lost due to processing error and were excluded from group b. New bone area was significantly greater for option b. compared to a. (p = 0.001), c. (p = 0.002), and d. (p = 0.046). Residual non-bone graft area was significantly less for option d. compared to a. (p = 0.026) or c. (p = 0.021). We conclude that collagen membranes with a prolonged resorption/barrier profile combined with bone substitutes featuring different degradation profiles sufficiently support new bone formation. Tacking strategy/membrane fixation appears redundant when using these biomaterials.

Lateral Ridge Augmentation with Guided Bone Regeneration Using Particulate Bone Substitutes and Injectable Platelet-Rich Fibrin in a Digital Workflow: 6 Month Results of a Prospective Cohort Study Based on Cone-Beam Computed Tomography Data

This study aimed to test whether or not a digital workflow for GBR with particulate bone substitutes and injectable platelet-rich fibrin improved the thickness of the hard tissue compared to the conventional workflow. 26 patients in need of lateral bone augmentation were enrolled. GBR with particulate bone substitutes and injectable platelet-rich fibrin was performed in all patients. Patients were divided into two groups: control (conventional workflow; n = 14) and test (digital workflow; n = 12). CBCT scans were performed before surgery, immediately after wound closure, and 6 months post-surgery, and the labial thickness of the hard tissue (LT) was assessed at 0–5 mm apical to the implant shoulder (LT₀–LT₅) at each time point. A total of 26 patients were included in this study. After wound closure, the test group showed significantly greater thickness in LT₀–LT₂ than the control group (LT₀: test: 4.31 ± 0.73 mm, control: 2.99 ± 1.02 mm; LT₁: test: 4.55 ± 0.69 mm, control: 3.60 ± 0.96 mm; LT₂: test: 4.76 ± 0.54 mm, control: 4.05 ± 1.01 mm; p < 0.05). At 6 months, significant differences in LT₀–LT₁ were detected between the groups (LT₀: test: 1.88 ± 0.57 mm, control: 1.08 ± 0.60 mm; LT₁: test: 2.36 ± 0.66 mm, control: 1.69 ± 0.58 mm; p < 0.05). Within the limitations of this study, the use of digital workflow in GBR with particulate bone substitutes and i-PRF exerted a positive effect on the labial thickness of hard tissue in the coronal portion of the implant after wound closure and at 6 months.

The Influence of Different Guided Bone Regeneration Procedures on the Contour of Bone Graft after Wound Closure: A Retrospective Cohort Study

The aim of this study was to evaluate the impact of different guided bone regeneration (GBR) procedures on bone graft contour after wound closure in lateral ridge augmentation. A total of 48 patients with 63 augmented sites were included in this study. Participants were divided into 4 groups (n = 12 in each group) based on different surgical procedures: group 1: particulate bone substitute + collagen membrane; group 2: particulate bone substitute + collagen membrane + healing cap, group 3: particulate bone substitute + injectable platelet-rich fibrin (i-PRF) + collagen membrane; group 4: particulate bone substitute + i-PRF + surgical template + collagen membrane. After wound closure, the thickness of labial graft was measured at 0–5 mm apical to the implant shoulder (T0–T5). At T0–T2, the thickness of labial graft in group 4 was significantly higher than the other three groups (p < 0.05). And group 4 showed significantly more labial graft thickness than group 1 and group 2 at T3–T5 (p < 0.05). Within the limitations of this study, the use of i-PRF in combination with the surgical template in GBR may contribute to achieving an appropriate bone graft contour after wound closure.

Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Technical Note

Horizontal bone reconstruction is a common augmentation procedure used in implant dentistry to achieve adequate 3-dimensional ridge reconstruction to permit proper dental implant positioning. However, most available techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate an innovative device that is indicated for bidirectional bone augmentation. The study consisted of 4 patients who required bidirectional horizontal bone augmentation of the upper jaw. Two computerized tomographies were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness in the studied sites at T0 was 2.30 ± 0.65 and mean bone thickness achieved was 9.11 ± 1.08 mm at T1, with an overall bone gain of 6.81 ± 1.33 mm. Concerning the specific gains in direction, buccal and palatal bone augmentations were 4.89 ± 0.94 and 1.92 ± 0.42 mm, respectively. Based on these results, it can be concluded that the use of this novel device allows for the achievement of bidirectional horizontal bone augmentation.