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

Complications and treatment errors in peri-implant hard tissue management

Bone augmentation procedures aim to regenerate the deficient alveolar ridge to properly place dental implants that are completely surrounded by bone. However, these are invasive and technically demanding surgeries that are not free of either complications or treatment errors. Careful patient selection and preparation is a mandatory process to reduce the rate of complications in bone regeneration procedures, irrespective of the technique used. It is important to assess the cost benefit of the intervention and to evaluate the potential impact on the patient's quality of life, especially in the elderly and medically compromised patients. Most common postoperative complications are wound dehiscences, which may be reduced, at least partially, by proper knowledge of the surgical technique and the craniofacial anatomy. Other complications that may appear are postoperative infections or nerve injuries. The aim of this narrative review is to summarize the best available scientific evidence on the incidence of complications, as well as the ideal strategies for their prevention and management. Depending on the severity of the complication, treatment approaches may vary and can include drug prescription or even surgical re-entries to remove exposed barrier membranes or contaminated bone grafts. Adequate prevention and proper management of complications associated with bone augmentation interventions are a requirement for clinicians carrying out these demanding procedures. A series of cases illustrating proper management of complications in different clinical scenarios is presented.

The L-shape technique in guided bone regeneration with simultaneous implant placement in the esthetic zone: A step-by-step protocol and a 2-14 year retrospective study

OBJECTIVES

To describe the methodology of the "L-shape" technique in guided bone regeneration (GBR) with simultaneous implant placement and report on the clinical, esthetic, and patient satisfaction outcomes up to 14 years of follow-up.

MATERIAL AND METHODS

Fourteen patients treated with the "L-shape" technique were included in this retrospective study. The L-shape technique was performed by trimming and placing a soft-type bone block made of deproteinized bovine bone mineral with 10% collagen at the buccal-occlusal aspect of the dental implant. The remaining gaps were filled with deproteinized bovine bone mineral granules and the augmented area was covered with a collagen membrane. The following parameters were recorded:  probing depth (PD), bleeding on probing (BOP), plaque index (PI), keratinized tissue width (KT) and marginal bone level (MBL). Esthetic outcomes were assessed according to the pink esthetic score (PES) and the white esthetic score (WES). Patient satisfaction was evaluated by means of a numerical rating scale (0-10). The stability of each augmented site was assessed by measuring the volumetric changes between baseline (crown delivery) and the respective follow-up.

RESULTS

A total of 13 maxillary incisors and one maxillary canine in 14 patients were included. The mean follow-up period was 7.7 ± 3.8 years. PES values amounted to 10.7 ± 3.3 and WES to 8.8 ± 1.4. Patient satisfaction reached 9.4 ± 0.8. Mean PD at implant sites were 2.7 ± 0.7 mm while BOP amounted to 15.0 ± 0.2% and Pl to 5.0 ± 0.0%. Volumetric analyses revealed minimal changes at the augmented sites irrespective of the region of interest. Radiographic MBL remained relatively stable.

CONCLUSIONS

Within the limitation of the present study the L-shape augmentation procedure seems to be a reliable technique when performing GBR with simultaneous implant placement in the esthetic zone. Outcomes encompassed stable clinical and esthetic results accompanied by high levels of patient satisfaction. Future randomized controlled trials are warranted to confirm possible benefits of the L-shape technique over traditional approaches.

CLINICAL SIGNIFICANCE

The L-shape appears to be a simple yet promising technique in GBR with simultaneous implant placement that can easily be translated into clinical practice.

Analysis of the biocompatibility of a biocelulose and a poly L- lactic acid membrane

The use of selective barriers as resorbable membranes has become a routine clinical procedure for guided bone regeneration. Therefore, the production of membranes with a low inflammatory potential during their resorption process has become the goal of a considerable number of researches. Aim: The purpose of the present study was to evaluate the biocompatibility of poly (L- lactic acid) (PLLA) and biocelulose membranes (BC) inserted in the subcutaneous tissue on the dorsum of rats. Methods: Fifteen animals underwent surgical procedures for the insertion of 4 types of membranes: COL (Collagen membrane) – Control Group; BC (Biocellulose membrane); BCAg (Biocellulose membrane impregnated with Silver); PLLA (Poly (L-lactic acid) membrane). All membrane types were inserted into each animal. Animals were euthanized after 3, 7, and 15 days of the surgical procedure. Descriptive histological analyses were carried out to investigate host tissue reaction to membrane presence by assessing the anti-inflammatory process composition associated with the membrane resorption and the presence of foreign-body reaction or encapsulation. Results: The BC membranes showed a higher degree of inflammation and poor pattern of integration with the surrounding tissues than the PLLA and COL membranes. Conclusion: The PLLA and COL membranes present better biocompatibility than the BC membranes.

Effect of collagen membrane fixation on ridge volume stability and new bone formation following guided bone regeneration

AIM

To test the effect of membrane fixation on ridge volume stability and new bone formation using guided bone regeneration.

MATERIALS AND METHODS

In eight beagle dogs, after bilateral extraction of the maxillary pre-molars, a box-shaped defect was created on each side. All defect sites were augmented with a particulate bone substitute material, covered with either one of two non-cross-linked collagen membranes (CM1 or CM2) with or without fixation (-F or -UF). Samples were collected after 8 weeks. Histomorphometric and micro-computed tomography analyses were performed.

RESULTS

Membrane fixation made no significant difference to the total augmented volume for both membranes (p > .05). Histological data indicated that at the ridge crest the augmented tissue width amounted to 2.4 ± 0.4 mm in the group CM1-F and 2.4 ± 0.5 mm in the group CM1-UF, with no significant difference between the groups. Conversely, in CM2-F the augmented tissue width was significantly larger than in CM2-UF (2.3 ± 0.1 vs. 1.57 ± 0.27, p < .05).

CONCLUSIONS

Membrane fixation in contained defects failed to improve ridge volume stability regardless of the membrane type. However, it may enhance the width of the augmented ridge at the coronal portion depending on the type of membrane.

Peri-implant bone augmentation by the sub-periosteal peri-implant augmented layer technique and a bovine-derived bone block: A case report

BACKGROUND

When used with deproteinized bovine bone mineral (DBBM) delivered as a particulate, the sub-periosteal peri-implant augmented layer (SPAL) technique was effective in completely correcting up to 92% of peri-implant buccal bone dehiscences. The use of a DBBM block (bDBBM), however, may result in an improvement of the peri-implant bone dehiscence as well as a relevant lateral bone augmentation since its mechanical properties may ensure a better dimensional stability at flap manipulation than particulate DBBM. The aim of the present a proof-of-principle case report is to investigate if SPAL may be successfully used to obtain bone augmentation at peri-implant dehiscence sites when used with bDBBM.

CASE PRESENTATION

Lateral bone augmentation was performed using the SPAL technique at two implants showing a buccal peri-implant bone dehiscence immediately after their placement. A partial-thickness flap was elevated, leaving the periosteal layer on the buccal cortical bone plate. The periosteal layer was, in turn, elevated to create a pouch, which was used to stabilize a bDBBM graft at the peri-implant buccal bone dehiscences. At re-entry, exposed implant surfaces were completely covered by new thick hard tissue up to their most coronal portion. A free epithelial-connective tissue graft was used to augment the peri-implant soft tissue phenotype.

CONCLUSION

When used to accommodate bDBBM over the most coronal portion of an exposed implant, SPAL may successfully lead to an increase in peri-implant buccal tissue thickness.

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.

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.

Use of a Novel In Situ Hardening Biphasic Alloplastic Bone Grafting Material for Guided Bone Regeneration around Dental Implants - A Prospective Case Series

INTRODUCTION

The novel bioresorbable polymer poly (lactide-co-glycolic acid) (PLGA) coated biphasic calcium phosphate material (BCP) hardens into a stable and porous hard tissue scaffold when exposed to body fluids. The self-containable, stable bone graft material might be beneficial for facilitating guided bone regeneration (GBR) around dental implants, especially for a defect with an absence of bony wall(s). The aim of this prospective case series is to evaluate the post-surgical implant survival and success where the in situ hardening BCP was used for GBR around dental implants.

CASE SERIES

Ten patients received 13 implants with simultaneous bone augmentation. Dehiscence and/or fenestration type of bony defect was detected in nine surgical sites, and three surgical sites exhibited a suprabony defect. In nine out of the 13 implants, a membrane was used in conjunction with the bone grafting. Patients were evaluated at the day of the surgery as well as 2 weeks, and 1, 3, 6, and 12 months postoperatively. All post-surgical wounds were uneventfully healed. Radiographic bone levels showed stability over time with an average bone loss/remodeling of 0.19 ± 0.6 mm (range, -0.5-1.5 mm) from implant placement to the last follow-up at 12 months. All implants survived after 12 months.

CONCLUSIONS

Implant placement with simultaneous bone grafting using the in situ hardening BCP, was shown to be a viable and safe procedure with stable clinical and radiographic results over the follow-up period. Further long-term studies are warranted, however, the combination of the ease of handling and the favorable results are promising.

Bone Regeneration Capability of 3D Printed Ceramic Scaffolds

In this study, we evaluated the bone regenerative capability of a customizable hydroxyapatite (HA) and tricalcium phosphate (TCP) scaffold using a digital light processing (DLP)-type 3D printing system. Twelve healthy adult male beagle dogs were the study subjects. A total of 48 defects were created, with two defects on each side of the mandible in all the dogs. The defect sites in the negative control group (sixteen defects) were left untreated (the NS group), whereas those in the positive control group (sixteen defects) were filled with a particle-type substitute (the PS group). The defect sites in the experimental groups (sixteen defects) were filled with a 3D printed substitute (the 3DS group). Six dogs each were exterminated after healing periods of 4 and 8 weeks. Radiological and histomorphometrical evaluations were then performed. None of the groups showed any specific problems. In radiological evaluation, there was a significant difference in the amount of new bone formation after 4 weeks (p < 0.05) between the PS and 3DS groups. For both of the evaluations, the difference in the total amount of bone after 8 weeks was statistically significant (p < 0.05). There was no statistically significant difference in new bone between the PS and 3DS groups in both evaluations after 8 weeks (p > 0.05). The proposed HA/TCP scaffold without polymers, obtained using the DLP-type 3D printing system, can be applied for bone regeneration. The 3D printing of a HA/TCP scaffold without polymers can be used for fabricating customized bone grafting substitutes.