Guided Bone Regeneration: CGF and PRF Combined With Various Types of Scaffolds-A Systematic Review

Objective: Bone regeneration plays a pivotal role in modern oral surgery, particularly in facilitating successful implant-prosthetic rehabilitation. This systematic review explores the regenerative potential of growth factors, such as platelet-rich fibrin (PRF) and concentrated growth factors (CGFs), when combined with various types of scaffolds in bone augmentation procedures, including guided bone regeneration, split crest, sinus lift (SL), and alveolar ridge preservation. Method: A comprehensive search strategy yielded 18 relevant studies, which were analyzed for bone formation and stabilization outcomes. Results: Results indicate that PRF enhances bone regeneration and stabilization in SL and ridge augmentation procedures, while CGFs facilitate surgical techniques and augment bone. However, some studies did not report significant differences. Growth factors also demonstrate benefits in wound healing, reducing bone resorption, and enhancing socket preservation. Conclusion: Despite valuable insights, further research is needed to comprehensively understand the characteristics of growth factors in various surgical interventions, ensuring informed decision-making in bone regeneration surgery.

Microarchitectural Study of the Augmented Bone Following a Modified Ridge Splitting Technique: Histological and Micro-Computed Tomography Analyses

Objectives: The aim of this matched prospective cohort study was to examine the microarchitecture of the augmented bone following a modified alveolar ridge splitting procedure and compare it to that of native bone. Methods: In the test group, patients underwent a modified ridge split osteotomy procedure to restore the width of the posterior segment of the mandible. Patients with sufficient bone width for dental implant placement in the posterior region of the mandible following 3-month-long spontaneous healing after tooth removal were included in the control group. In both study groups, bone biopsy samples were harvested and dental implants were placed. Histomorphometry and micro-CT analysis were performed. Results: Altogether, 15 patients were included in this study (7 patients in the test group, with 14 bone core biopsies harvested, and 8 patients in the control group, with 13 bone core biopsies harvested). Percentage bone volume (BV/TV) in the micro-CT analysis (22.088 ± 8.094% and 12.075 ± 4.009% for the test and control group, respectively) showed statistically significant differences between study groups. Conclusions: Based on histological and micro-CT analyses, the modified ridge splitting procedure with autologous bone block harvested from the retromolar area results in a dental implant recipient bone microarchitecture superior to that of the extraction sockets left to heal undisturbed for a 3-month-long healing period.

The influence of bone block graft position on bone dimensional changes in staged onlay horizontal ridge augmentation: A 6-month retrospective cohort study

OBJECTIVES

To analyze changes in bone dimensions and their modulating factor in bone dimensions 6 months after horizontal ridge augmentation using autogenous bone grafts.

MATERIALS AND METHODS

Thirty-eight patients with horizontally atrophic alveolar ridges of a single edentulous tooth at the maxillary anterior site were divided into two groups based on the fixation position of the bone block during ridge augmentation surgery (H0, vertical distance from the upper edge of the bone block to the alveolar crest). Patients were classified into a crestal level (CL) group if H0 ≤ 1 mm and a sub-crestal level (SCL) group if H0 > 1 mm. The width and height of the alveolar ridge were recorded using CBCT both before and 6 months after the augmentation procedure.

RESULTS

The CL group comprised 20 patients with 23 implants, whereas the SCL group comprised 18 patients with 22 implants. All the augmentation sites exhibited vertical bone resorption. Vertical bone resorption in the SCL group (1.94 ± 2.11 mm) was significantly higher than that of the CL group (0.61 ± 0.64 mm). The SCL group showed significantly lower horizontal bone gain than the CL group (SCL: 1.02 ± 2.30 mm; CL: 3.19 ± 3.17 mm) at the cervical level. Peri-implant marginal bone loss increased significantly in the SCL group (1.00 ± 2.71 mm) compared to the CL group (0.64 ± 0.40 mm).

CONCLUSION

The bone height decreased after horizontal ridge augmentation using autogenous onlay grafting. The fixation position of the bone block was a modulating factor. The SCL group showed more vertical bone loss, less horizontal bone gain 6 months after surgery, and more marginal bone loss after restoration.

Cortical Block Grafting Successfully Augments Alveolar Cleft Sites for Dental Implant Placement

BACKGROUND

Supplemental bone grafting is regularly required before dental implant placement in patients with cleft lip and palate (CLP).

PURPOSE

The study purpose was to measure and compare implant osseointegration and changes in graft dimensions following lateral incisor onlay cortical bone grafting in CLP and non-CLP patients.

STUDY DESIGN, SETTING, SAMPLE

Retrospective cohort study composed of patients who presented to Boston Children's Hospital and underwent autogenous onlay cortical block bone grafting at lateral incisor sites from 2015 through 2023. Patients were excluded if the cone beam computed tomography (CBCT) quality was insufficient for accurate measurements.

PREDICTOR VARIABLE

The predictor variable was CLP status coded as CLP or non-CLP.

MAIN OUTCOME VARIABLE

The primary outcome variable was successful implant osseointegration confirmed by a torque of 35 N/cm or more after 3 months of implant healing. Secondary outcomes were change in bone width between preoperative and postoperative CBCT scans at lateral incisor sites and the need for additional bone augmentation prior to or during implant placement.

COVARIATES

Covariates were age, sex, cleft location, and time from bone graft to postoperative CBCT and implant placement.

ANALYSES

Data analyses were performed using t-tests, Fisher's exact tests, Mann-Whitney U tests, and Pearson's correlation. P < .05 was considered statistically significant.

RESULTS

A total of 22 subjects (16 with CLP) were evaluated. The mean age at the time of graft was 19.3 ± 2.4 years with 52.6% males. Implants were osseointegrated at 20 of 22 lateral incisor sites (1 CLP failure, 1 non-CLP failure). There was significant change in bone width after grafting for patients with CLP (P < .001). Patients with CLP experienced a 3.32 (± 1.80) mm and 2.99 (± 1.61) mm increase in bone width at 2 different levels. Patients with CLP achieved greater boney changes near the alveolar crest than noncleft patients (P = .008) but the change was not significantly different more apically (P = .86). One subject with CLP required additional grafting during implant placement.

CONCLUSION AND RELEVANCE

Cortical block onlay bone grafting is a predictable technique to augment lateral incisor sites in patients with CLP for placement of a dental implant.

Efficacy of the Sausage Technique in Rebuilding the Crestal Buccal Bone Thickness: A Retrospective Analysis

The goal was to evaluate the efficacy of the sausage technique in reconstructing the crestal buccal bone thickness, focusing on the distribution shape of the regenerated volume. Ten implants were placed in five patients with Cawood-Howell class IV defects. A cone beam computed tomography (CBCT) was executed at T0 (before surgery). Guided bone regeneration (GBR) with the sausage technique utilized a resorbable collagen membrane, made of a 50% autologous bone and a 50% anorganic bovine bone matrix (ABBM) mixture. After 6 months, a CBCT (T1) was performed before implant placement. Using CBCT software, a plane parallel to the implant axis intersected perpendicular planes every 1.5 mm from the crest level. T0 and T1 CBCT sections were analyzed, yielding 140 measurements. Statistical analysis via SPSS revealed a significant increase in thickness (average 2.82 ± 1.79 mm). Maximum gains occurred at 4.5 mm from the coronal crest line (3.8 ± 1.51 mm). The GBR sausage technique was effective with minimal post-operative complications, yielding the biggest gain at the mid-ridge sagittal area. Within the analysis limitations, it can be assumed that the sausage technique is effective for horizontal GBR in the maxilla, but a lesser volume might be achieved at the crestal level because it seems to follow a bowed regeneration shape.

Evaluating risk factors and complications in mandibular ramus block grafting: a retrospective cohort study

OBJECTIVES

This retrospective cohort study aimed to identify the complications and risk factors associated with alveolar grafting using autologous mandibular ramus grafts, guided by the research question: What are the complications encountered in patients undergoing alveolar bone grafting using autologous mandibular ramus block and what are the risk factors associated with the development of these complications?

MATERIALS AND METHODS

The study included 70 patients who underwent alveolar crest augmentation with autologous mandibular ramus block grafting. Intraoperative, early postoperative, and late postoperative complications were analyzed, as were various risk factors.

RESULTS

The results showed that the majority of patients had successful outcomes with minimal complications. Sex was found to significantly influence the visibility of the inferior alveolar nerve (IAN). Early postoperative complications were associated with IAN visibility and the use of a single screw for graft fixation. Late postoperative complications were significantly associated with the presence of infection.

CONCLUSION

The findings emphasize the importance of careful surgical techniques, infection prevention, and patient selection in minimizing complications.

CLINICAL RELEVANCE

This article may contribute to clinicians' and so patients' understanding of potential risk factors associated with over all ramus block grafting procedure. Based on this information, clinicians can also improve their ability to manage risk factors and associated complications and compare ramus block grafting with other alternatives to determine the best treatment approach for that particular patient.

3D-printed bredigite scaffolds with ordered arrangement structures promote bone regeneration by inducing macrophage polarization in onlay grafts

Bone tissue engineering scaffolds may provide a potential strategy for onlay bone grafts for oral implants. For determining the fate of scaffold biomaterials and osteogenesis effects, the host immune response is crucial. In the present study, bredigite (BRT) bioceramic scaffolds with an ordered arrangement structure (BRT-O) and a random morphology (BRT-R) were fabricated. The physicochemical properties of scaffolds were first characterized by scanning electron microscopy, mechanical test and micro-Fourier transform infrared spectroscopy. In addition, their osteogenic and immunomodulatory properties in an onlay grafting model were investigated. In vitro, the BRT-O scaffolds facilitated the macrophage polarization towards a pro-regenerative M2 phenotype, which subsequently facilitated the migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. In vivo, an onlay grafting model was successfully established in the cranium of rabbits. In addition, the BRT-O scaffolds grafted on rabbit cranium promoted bone regeneration and CD68 + CD206 + M2 macrophage polarization. In conclusion, the 3D-printed BRT-O scaffold presents as a promising scaffold biomaterial for onlay grafts by regulating the local immune microenvironment.

Biomaterial scaffolds in maxillofacial bone tissue engineering: A review of recent advances

Maxillofacial bone defects caused by congenital malformations, trauma, tumors, and inflammation can severely affect functions and aesthetics of maxillofacial region. Despite certain successful clinical applications of biomaterial scaffolds, ideal bone regeneration remains a challenge in maxillofacial region due to its irregular shape, complex structure, and unique biological functions. Scaffolds that address multiple needs of maxillofacial bone regeneration are under development to optimize bone regeneration capacity, costs, operational convenience. etc. In this review, we first highlight the special considerations of bone regeneration in maxillofacial region and provide an overview of the biomaterial scaffolds for maxillofacial bone regeneration under clinical examination and their efficacy, which provide basis and directions for future scaffold design. Latest advances of these scaffolds are then discussed, as well as future perspectives and challenges. Deepening our understanding of these scaffolds will help foster better innovations to improve the outcome of maxillofacial bone tissue engineering.

Treatment of peri-implant soft tissue dehiscence around implants placed in calvarial bone graft maxilla and mandible 20 years ago: A case report

INTRODUCTION

Despite tissue augmentation and management prior implantation, long-term observation can reveal a change in peri-implant phenotype with some lack of keratinized mucosa (KM). The treatment approach of peri-implant dehiscence in multiple implants is not clearly defined. This report describes the different periodontal surgical approaches undertaken to promote the gingival margin stability and to prevent the peri-implant mucosal inflammation over time.

CASE PRESENTATION

A 64-year-old woman with peri-implant tissue dehiscence regarding implants placed 20 years ago in a calvarial bone grafted maxilla and mandible was treated. Right maxillary and mandible peri-implants soft tissue were treated with a large apically positioned partial-thickness flap (APPTF) combined to a free gingival graft (FGG) simultaneously. For the left maxillary, where a frenum was in tension associated with infection and pockets, a large APPTF followed by a FGG 4 months later were performed. The KM width (KMW) increased in three operated sites with a gain average of 2.2 mm. The plaque control record decreased from 68% to 21%. All the probing depths were lower than 3 mm. Bleeding on probing was significantly reduced. The gingival index (GI) went from 1.5 to 0.25.

CONCLUSION

In a multiple implants soft tissue dehiscence case, an APPTF associate to a FGG, delayed or not, seems to be a safety primary approach to improve the KMW and to stabilize the peri-implants soft tissue. Further, a connective tissue graft in a bilaminar approach could be an option to enhance soft tissue thickness and esthetic outcomes.

KEY POINTS

Why is this case new information? To the best of the authors' knowledge, there are very limited studies regarding multi-implant soft tissue dehiscence treatment. Relevant guidelines are not clearly defined. Despite peri-implant hard and soft tissue augmentation, after a long-term observation (20 years of function), we can observe a change in peri-implant soft tissue phenotype (PISTP) with periodontal complication. What are the keys to successful management of this case? Removal of peri-implant infection and tissue tension (frenum) by a large apically positioned partial-thickness flap (APPTF) before soft tissue augmentation procedure. In case of very thin peri-implant soft tissue, caution is needed to preserve the blood supply from the supra-periosteal plexus. Large APPTF and sufficient amount of keratinized mucosa (KM) should be grafted to compensate for the tissue shrinkage. What are the primary limitations to success in this case? High esthetic demand. A secondary bilaminar approach with a connective tissue graft (CTG) should be necessary to improve the esthetic outcomes. Patient compliance.

Clinical feasibility evaluation of a digital workflow of prosthetically oriented onlay bone grafting for horizontal alveolar augmentation: a prospective pilot study

BACKGROUND

Onlay bone grafting is considered highly reliable for reconstructing severe horizontal bone defects. A critical problem is how to achieve precise position of the bone block to control alveolar ridge dimensions. This research aims to establish a digital workflow for prosthetically oriented onlay bone grafting and evaluate its accuracy and efficiency.

METHODS

This prospective pilot study investigated eight patients who required implant restoration in the esthetic area with horizontal alveolar bone defects. The workflow includes preoperative virtual planning, design and manufacture of patient-specific templates, bone grafting surgery, and implant insertion. Primary outcomes were graft accuracy, defined by root mean square estimate (RMSE) values between preoperatively designed and actual implanted outer contours of bone blocks. Secondary outcomes were bone graft and implant success rates. Besides, the surgeons used the visual analog scale (VAS) to rate the intuitiveness, ease of understanding, and helpfulness of the workflow.

RESULTS

No bone grafts or implants failed in any of the eight patients, resulting in a 100% success rate. The RMSE values between the preoperative design and the implanted outer contour of bone blocks were 0.41 ± 0.15 mm. The digital approach showed advantages in intuitiveness (9.3 ± 0.5), understanding (9.0 ± 0.5), and helpfulness (8.4 ± 1.1) according to surgeons' VAS scores.

CONCLUSIONS

A digital workflow provided encouraging results, in terms of accuracy and efficacy, for horizontal bone augmentation.

TRIAL REGISTRATION

This study was registered in the National Clinical Trials Registry in 16/02/2023 under the identification number ChiCTR2300068361.

Simultaneous or staged lateral ridge augmentation: A clinical guideline on the decision-making process

Lateral ridge augmentation is a standard surgical procedure that can be performed prior to (staged) or simultaneously with implant placement. The decision between a simultaneous or staged approach involves considering multiple variables. This paper proposed a decision-making process that serves as a guideline for choosing the best treatment choice based on the available evidence and the author's clinical experience.

Vertical ridge augmentation of atrophic posterior mandible with corticocancellous onlay symphysis graft versus sandwich technique: clinical and radiographic analysis

Alveolar ridge augmentation of atrophic posterior mandibular ridge represents a challenge in oral and maxillofacial surgery to restore aesthetic and function. The aim of the study was to compare the clinical and radiographic outcomes of bone formation in atrophic posterior mandibles augmented using onlay symphysis cortico-cancellous bone block with that augmented using sandwich bone augmentation technique (Inlay). Twelve patients were selected with missing mandibular posterior teeth. CBCT were done for all patients preoperatively to assess the residual bone height, ranged between 5 and 7 mm from the inferior alveolar nerve with adequate sufficient alveolar ridge width more than 4 mm. Patients required bone augmentation procedure with autologous onlay chin graft (group I) versus those used as inlay sandwich technique (group II). Clinical and radiographic analysis were done to analyses the newly formed bone and bone height. Percent of change in bone height was also calculated and revealed that group I was higher than group II, however, statistically insignificant differences between the two groups were found regarding the percentage of newly formed bone. Vertical ridge augmentation procedures using onlay chin graft took lesser time than the interpositional grafting with fixation technique, however, both techniques are promising for vertical ridge augmentation.

Bone reconstruction of extensive maxillomandibular defects in adults

Reconstruction of significant maxillomandibular defects is a challenge that has been much discussed over the last few decades. Fundamental principles were developed decades ago (bone bed viability, graft immobilization). Clinical decision-making criteria are highly relevant, including local/systemic factors and incision designs, the choice of material, grafting technique, and donor site morbidity. Stabilizing particulated grafts for defined defects-that is, via meshes or shells-might allow significant horizontal and vertical augmentation; the alternatives are onlay and inlay techniques. More significant defects might require extra orally harvested autologous bone blocks. The anterior iliac crest is often used for nonvascularized augmentation, whereas more extensive defects often require microvascular reconstruction. In those cases, the free fibula flap has become the standard of care. The development of alternatives is still ongoing (i.e., alloplastic reconstruction, zygomatic implants, obturators, distraction osteogenesis). Especially for these complex procedures, three-dimensional planning tools enable facilitated planning and a surgical workflow.

Efficacy of autogenous tooth block for lateral ridge augmentation compared with autogenous bone block: A systematic review and meta-analysis

BACKGROUND

Autogenous tooth block (ATB) has been used as an alternative material for bone regeneration, but its efficacy compared with autogenous bone block (ABB) remains uncertain. The aim of this systematic review was to investigate and compare the clinical and histological performance of ATB and ABB grafts in lateral alveolar ridge augmentation (LARA).

METHODS

Electronic retrieval of MEDLINE, Embase, Cochrane Library (CENTRAL), Scopus, Web of Science, China national knowledge infrastructure, Wanfang data, SinoMed, and manual searching until July 2023 were used to identify controlled clinical trials employing ATB grafts in LARA. The identified reports included at least one of the following outcome variables: ridge width gain, graft resorption, postoperative complications, histology, and histomorphometry. Weighted or mean differences (MD), relative risk, and corresponding 95% confidence intervals (CI) were calculated. Descriptive analysis was applied to the qualitative statistics. The protocol followed the preferred reporting items for systematic reviews and meta-analyses statement and was prospectively registered in PROSPERO (CRD42023399611).

RESULTS

Four controlled clinical trials with 77 participants each using ATB and ABB grafts were included. Meta-analysis indicated that ATB grafts resulted in greater bone width (MD = 1.31, 95% CI [0.92, 1.71], P < .00001) and less graft resorption (MD = -0.71, 95% CI [-1.22, -0.21], P = .005) than ABB grafts on LARA. There was no statistical difference in postoperative complications between ATB and ABB grafts (relative risk = 0.81, 95% CI [0.32, 2.04], P = .66). Furthermore, the ATB grafts exhibited positive replacement resorption with alveolar bone for favorable signs of new bone activity on histology and histomorphometry.

CONCLUSION

Within the limitations of this study, ATB grafts could serve as an alternative material for ABB to support LARA. Further research with a longer follow-up period is required to verify these findings.

Progression of experimental peri-implantitis in guided bone regeneration and pristine bone: A preclinical in vivo study

BACKGROUND

Guided bone regeneration (GBR) is the most widely used technique for overcoming the deficiency of alveolar bone. However, the progression of peri-implantitis in regenerative and pristine bone sites has not been fully investigated. The aim of this study is to compare experimental peri-implantitis around implants placed in pristine bone and GBR sites.

METHODS

Bilateral  mandibular first molars were extracted from six beagle dogs, and standardized horizontal ridge defect was simultaneously created at predetermined site in unilateral mandible. After 8 weeks, guided bone regeneration procedure was conducted at the defect site. After 16 weeks, implants (ϕ 3.6×8.0 mm) were placed at both extracted sites. This study included 3 months of active breakdown and another 3 months of spontaneous progression period. Radiographs were taken at each phase and specimens were obtained for histological, immunohistochemical, and polarized light microscopic analysis.

RESULTS

Marginal bone loss around implant did not show the significant differences between pristine bone and GBR sites during spontaneous progression period. In immunohistochemical analysis, inflammatory and immune-related cells were predominantly detected in peri-implantitis-affected area rather than unaffected area. In the polarized light microscopic analysis, substantial reductions in the amount and thickness of collagen fibers were observed in peri-implantitis-affected area compared with unaffected tissues. However, there were no significant differences in histological, immunohistochemical, polarized light microscopic outcomes between pristine bone and GBR sites.

CONCLUSION

Previous hard tissue grafting at the implant sites did not affect experimental peri-implantitis and exhibited similar radiographic, histological, immunohistochemical, and polarized light microscopic outcomes compared with those of pristine bone sites.

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.

Radiographic evaluation of the tenting screw technique in horizontal alveolar bone augmentation: A retrospective study

OBJECTIVES

To radiographically analyze the effects of tenting screw technique (TS) and onlay bone grafts (OG) in horizontal bone augmentation.

MATERIALS AND METHODS

Patients receiving horizontal bone augmentation by TS or OG were selected. The clinical outcomes and cone beam computed tomography (CBCT) data were documented pre-grafting, immediately post-grafting, before and after implantation. The survival rates, clinical complications, alveolar bone width, and volumetric bone augmentation were evaluated and statistically analyzed.

RESULTS

A total of 25 patients and 41 implants were involved in this study, with no grafting failures observed in either the TS group (n = 20) or the onlay group (n = 21). Volumetric bone resorption rate in the TS group (21.34%) was significantly lower than that of the OG group (29.38%). In addition, significant horizontal bone gain was achieved in both groups (TS: 6.15 ± 2.12 mm; OG: 4.86 ± 1.40 mm) during the recovery period, with higher gain in the TS group. No apparent statistical difference in terms of volumetric bone gain was observed between the TS (748.53 mm³ , 607.47 mm³ ) and OG group (811.77 mm³ , 508.49 mm³ ) immediately post-grafting or after the recovery period.

CONCLUSION

Both TS and OG achieved satisfactory bone augmentation effects, yet TS resulted in more bone augmentation and better stability than OG, with a reduced use of autogenous bone. Overall, the tenting screw technique can serve as an effective alternative to autogenous bone grafts.

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

Objectives

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

Material and Methods

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

Results

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

Conclusions

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

The use of autologous bone for augmentation procedures leads to low prevalence of peri-implantitis-a retrospective study over a 20-year period

The aim of this study was to compare the prevalence of peri-implantitis in implants inserted into pristine bone (control) to implants where autologous bone was used for grafting procedures (study). All patients who underwent implant surgery during a 20 years interval by one maxillofacial implant surgeon and received a prosthodontic rehabilitation afterwards were eligible for inclusion in the study. Periimplant bone resorption and periimplant disease were assessed. Of 421 patients 384 (91.2%) patients responded to a recall after having been treated over a 20-year period by one maxillofacial surgeon and several dentists. A total of 110 patients had 239 implants in pristine bone, and 274 patients had 607 implants placed in combination with autologous bone grafting procedures. Mean time in function was 74 months (range 15-236 months). In all, 342 implants (34.8%) were in function for longer than 7 years. A total of 64 implant sites (7.6%) in 39 patients (10.2%) showed signs of peri-implant mucositis. In addition, 17 implants (2.0%) in 14 patients (3.6%) revealed signs of peri-implantitis, of which five implants were in the control group (2.09%) whereas 12 implants were in the study group (1.98%), with no statistically significant difference (p = 0.8405). More than half of the patients with peri-implantitis had a history of periodontitis. Three implants were lost due to peri-implantitis and four implants failed for other reasons, resulting in an overall success rate of 99.2% in 846 implants. CONCLUSIONS: Within the limitations of the study it seems that the use of autologous bone still is a relevant option when performing augmentation procedures because of the low prevalence of peri-implantitis.

Controversies in the dental implant treatment planning for anterior maxillary aesthetic zone - A review

The anterior maxillary region being an aesthetic zone remains critical in decision-making when it comes to replacing a tooth. Treatment planning to place dental implants in aesthetic zone like anterior maxilla needs paramount attention in order to provide best of the treatment outcomes from aesthetic point of view. As the field of dental implants tend to evolve continuously, newer concepts with inadequate research come into practise on regular basis. In this article, some of the controversies regarding dental implant placement and treatment process related to anterior maxillary aesthetic zone are discussed with literature to support evidence.

Risk Factors for Complications Following Staged Alveolar Ridge Augmentation and Dental Implantation: A Retrospective Evaluation of 151 Cases with Allogeneic and 70 Cases with Autogenous Bone Blocks

Purpose: the aim of this study was to identify potential risk factors favoring complications by assessing the number and types of complications associated with allogeneic or autogenous bone blocks applied as onlay grafts for alveolar ridge augmentation prior to implantation. Methods: A retrospective chart review on the success of 151 allogeneic and 70 autogenous bone blocks in a cohort of 164 consecutive patients, who were treated over a period of 6 years by the same surgeon, was conducted. Statistical conclusions were based on ROC curves and multiple logistic regression models. Results: Complications were observed more frequently with autogenous bone blocks (14 out of 70 cases; 20%) compared to allogeneic bone blocks (12 out of 151 cases; 7.9%; p = 0.013). However, these complications were minor and did not impact the successful dental rehabilitation. In a multiple logistic regression model, the risk of a complication was increased by the use of an autogenous bone block (OR = 3.2; p = 0.027), smoking (OR = 4.8; p = 0.007), vertical augmentation above a threshold of 2.55 mm (OR = 5.0; p = 0.002), and over-contouring (OR = 15.3; p < 0.001). Conclusions: Overall, the complication rate of ridge augmentations carried out with autogenous or allogeneic bone blocks was low. Despite previous recommendations, over-contouring and a vertical augmentation above a threshold of 2.55 mm should be avoided.

Autogenous Chin Block Grafts for Implant-Supported Rehabilitation: A 20-Year Follow-Up Case Series

The aim of the present study was to analyze the survival and success rates of dental implants placed in atrophic alveolar ridges reconstructed with mandibular symphysis autogenous onlay bone grafts, with a 20-year follow-up. A sample of five patients referred to the authors' department between 2000 and 2001 seeking for an implant-supported fixed rehabilitation. Patients were treated by means of autogenous bone blocks grafted from the mandibular symphysis and covered with bone substitutes (DBB) and a resorbable membrane. Then delayed implants were placed and finally prosthetic restoration was performed. In total, 10 implants placed in 5 patients were evaluated with a follow-up of 20 years. Both implant survival and success rate were 100%. The mean marginal bone loss was 0.32  [[EQUATION]]  0.39 mm (range 0-1.3 mm). Considering the conditions of peri-implant hard and soft tissues, the diagnosis of peri-implant health was made for all the implants included. According to this study, implants placed in alveolar ridges augmented by means of autogenous chin bone grafts showed long-term survival and high success rates. A correct management of peri-implant soft tissues and an accurate prosthetic rehabilitation are also fundamental to obtain the durable success of the treatment.

Fully digital versus conventional workflow for horizontal ridge augmentation with intraoral block bone: A randomized controlled clinical trial

OBJECTIVES

To compare the outcome and efficiency of the computer-aided intraoral block bone grafting procedure with those of the conventional technique for the augmentation of horizontal ridge defects.

MATERIALS AND METHODS

A total of 28 patients with single missing tooth in esthetic zone with class IV horizontal alveolar bone defect in need of dental implant restoration were recruited. Computer-aided design of the implant restoration and intraoral block bone grafting was performed for all the participants. The patients were randomly and equally divided into guide and control groups. A fully guided bone harvesting, trimming, and grafting surgery was executed in the guide group. The control group patients underwent surgery without any guide. After 6 months, all the patients underwent implant placement. The primary outcomes were the root mean square estimate (RMSE) values between the outer contours of the actual implanted and planned bone block as well as the RMSE values between the inner surface of the implanted bone block and the original bone surface of the recipient site immediately after surgery. The secondary outcomes were the trimming time of bone block and the surgery-associated complications. The postoperative visual analog scale (VAS) of pain, swelling, and mouth opening difficulty was recorded.

RESULTS

All 28 patients underwent intraoral block bone grafting, followed by the placement of implant after 191.8 ± 19.69 days. The RMSE values between the outer contours of the implanted and planned bone blocks were significantly lower in the guide group (0.37 ± 0.16 mm) as compared to those in the control group (0.72 ± 0.29 mm) (p = 0.0007). The RMSE values between the inner contours of the graft block and original bone at the recipient site were lower in the guide group (0.35 ± 0.15 mm) as compared to those in the control group (0.48 ± 0.17 mm) (p = 0.043). The duration of bone block trimming was shorter in the guide group (401.51 ± 97.60 s) as compared to the control group (602.36 ± 160.57 s) (p = 0.0005). In the control group, two patients received secondary bone grafting, one patient experienced bleeding of donor site and temporary hypoesthesia of the lower lip and chin skin, and one patient developed temporary sensitivity of the adjacent tooth.

CONCLUSIONS

As compared to the conventional procedure, the fully digital workflow in the present study seemed to be a more accuracy and effective protocol for horizontal ridge augmentation with intraoral block bone.

TRIAL REGISTRATION

Chictr.org.cn (ChiCTR2000036390).

Osseointegration Levels of Implants Placed With Allogenic and Xenogenic Bone Ring: An Experimental Biomechanical Analysis

This in vivo study aimed to do a biomechanical analysis of the early period bone-implant connection of titanium implants simultaneously inserted with xsenogenic and allogenic bone ring. In this study, 28 Sprague Dawley female rats were used. Four rats were killed to obtain an allogenic bone ring, and after this, the remaining rats were divided into control (n=8), xsenogenic (n=8), and allogenic (n=8) bone ring groups. Titanium-machined surfaced implants were integrated right tibias of the rats. In controls, only implants were integrated into right tibias. In the greft groups, the implants were integrated simultaneously with bone rings. After 2 weeks of the experimental period, the rats were killed ,and titanium implants and surrounding bone tissues were removed for biomechanic analysis. After biomechanical reverse torque analysis bone-implant connection was determined as Newton/cm2; in controls 3.26 (1.2 to 4.5), in allogenic ring group 3.37 (2 to 4.4), in xsenogenic ring group 5.93 (2.8 to 10). Statistically significant differences were not detected between the groups (P>0.05). Within the limitation of this study, both allogenic and xsenogenic bone grafts could be successfully used in bone augmentation in implant surgery.

Development and regeneration of periodontal supporting tissues

Periodontal tissues, including gingiva, cementum, periodontal ligament, and alveolar bone, play important roles in oral health. Under physiological conditions, periodontal tissues surround and support the teeth, maintaining the stability of the teeth and distributing the chewing forces. However, under pathological conditions, with the actions of various pathogenic factors, the periodontal tissues gradually undergo some irreversible changes, that is, gingival recession, periodontal ligament rupture, periodontal pocket formation, alveolar bone resorption, eventually leading to the loosening and even loss of the teeth. Currently, the regenerations of the periodontal tissues are still challenging. Therefore, it is necessary to study the development of the periodontal tissues, the principles and processes of which can be used to develop new strategies for the regeneration of periodontal tissues. This review summarizes the development of periodontal tissues and current strategies for periodontal healing and regeneration.

Comparison of the 3D-Microstructure Between Alveolar and Iliac Bone for Enhanced Bioinspired Bone Graft Substitutes

In oral- and maxillofacial bone augmentation surgery, non-vascularized grafts from the iliac crest demonstrate better clinical performance than alveolar bone grafts. The underlying mechanisms are not fully understood but are essential for the enhancement of bone regeneration scaffolds. Synchrotron Radiation µ-CT at a pixel size of 2.3 μm was used to characterize the gross morphology and the vascular and osteocyte lacuna porosity of patient-matched iliac crest/alveolar bone samples. The results suggest a difference in the spatial distribution of the vascular pore system. Fluid simulations reveal the permeability tensor to be more homogeneous in the iliac crest, indicating a more unidirectional fluid flow in alveolar bone. The average distance between bone mineral and the closest vessel pore boundary was found to be higher in alveolar bone. At the same time, osteocyte lacunae density is higher in alveolar bone, potentially compensating for the longer average distance between the bone mineral and vessel pores. The present study comprehensively quantified and compared the 3D microarchitecture of intraindividual human alveolar and iliac bone. The identified difference in pore network architecture may allow a bone graft from the iliac crest to exhibit higher regeneration potential due to an increased capacity to connect with the surrounding pore network of the residual bone. The results may contribute to understanding the difference in clinical performance when used as bone grafts and are essential for optimization of future scaffold materials.

Horizontal ridge augmentation in the anterior maxilla with in situ onlay bone grafting: a retrospective cohort study

OBJECTIVES

This study aimed to introduce a digitally guided in situ autogenous onlay grafting technique and compare its effectiveness with the conventional (ex situ) onlay technique in augmenting horizontal bone defects of the anterior maxilla.

MATERIALS AND METHODS

This retrospective cohort study included 24 patients who had received autogenous onlay bone grafts combined with guided bone regeneration (GBR) in the anterior maxilla. Fourteen patients were recruited into the in situ onlay grafting group (EG), and 10 were recruited into the ex situ onlay group (CG), defined by the donor sites. The clinical parameters, radiographic changes, micro-CT, and histological processes were evaluated after a mean follow-up period of 1.7 years.

RESULTS

The horizontal bone width reflected significant bone modeling over time (p < 0.001) in the first 6 months. Multivariable analysis showed that the treatment modality (grouping) was a critical factor positively associated with vertical bone height alteration. However, neither the alteration rate of horizontal bone width nor the bone volume was associated with the treatment modality. The number of periosteal screws per graft positively affected horizontal contour maintenance (p < 0.05). No significant differences were observed between the groups in the clinical parameters (complications, success rate, and peri-implant parameters). The micro-CT and histological outcomes were similar between the groups.

CONCLUSION

Despite the limitations of this study, in situ onlay grafting combined with GBR was an effective and reliable approach for horizontal bone augmentation in the anterior maxilla and appeared to demonstrate better stability in vertical bone remodeling.

CLINICAL RELEVANCE

This study introduces a modified and minimally invasive technique of onlay grafting for horizontal bone augmentation. This in situ onlay grafting demonstrates superior stability in vertical bone remodeling. The trial registration number is ChiCTR2100054683.

Horizontal augmentation techniques in the mandible: a systematic review

Purpose

Placement of dental implants has evolved to be an advantageous treatment option for rehabilitation of the fully or partially edentulous mandible. In case of extensive horizontal bone resorption, the bone volume needs to be augmented prior to or during implant placement in order to obtain dental rehabilitation and maximize implant survival and success.

Methods

Our aim was to systematically review the available data on lateral augmentation techniques in the horizontally compromised mandible considering all grafting protocols using xenogeneic, synthetic, or allogeneic material. A computerized and manual literature search was performed for clinical studies (published January 1995 to March 2021).

Results

Eight studies ultimately met the inclusion criteria comprising a total of 276 procedures of xenogeneic, allogeneic, or autogenous bone graft applications in horizontal ridge defects. Particulate materials as well as bone blocks were used as grafts with a mean follow-up of 26.0 months across all included studies. Outcome measures, approaches and materials varied from study to study. A gain of horizontal bone width of the mandible with a mean of 4.8 mm was observed in seven of eight studies. All but one study, reported low bone graft failure rates of 4.4% in average.

Conclusions

Only limited data are available on the impact of different horizontal augmentation strategies in the mandible. The results show outcomes for xenogeneic as well as autologous bone materials for horizontal ridge augmentation of the lower jaw. The use of allogeneic bone-block grafts in combination with resorbable barrier membranes must be re-evaluated. Randomized controlled clinical trials are largely missing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-022-00421-7.

Horizontal guided bone regeneration on knife-edge ridges: A retrospective case-control pilot study comparing two surgical techniques

INTRODUCTION

Studies evaluating guided bone regeneration (GBR) on knife-edge ridges using absorbable membranes with staged approaches have reported various horizontal bone gains. This study compared the horizontal bone gain obtained via a conventional technique of GBR and a recently-reported technique. Bone loss during the healing process was also measured.

METHODS

Consecutive patients who underwent GBR on knife-edge ridges via a conventional technique (control group) or the Sausage Technique (test group) were included in this study. GBR was performed using a collagen membrane and deproteinized bovine bone mineral combined with an autogenous graft at a 1:1 ratio. Cone-beam computed tomography (CBCT) was performed preoperatively, postoperatively, and after the patient healed. Horizontal bone width was measured on CBCT images 2 mm apical from the top of the crest. The preoperative CBCT and posthealing CBCT were superimposed to calculate the bone gain after healing, and the preoperative and postoperative CBCT scans were superimposed to calculate the bone gain after surgery. Bone loss during healing was calculated by subtracting the width of the ridge after healing from the postoperative width.

RESULTS

The mean horizontal bone gain was significantly lower in the control group (2.7 ± 1.8 mm; 83.2%) than in the test group (5.3 ± 2.3 mm; 216.8%) (p = 0.003). The average horizontal bone loss between regeneration and implant placement was 0.9 mm in the control group (27.9%) and 2.1 mm in the test group (29.4%). While the absolute bone loss was significantly different (p = 0.012), the percentage of bone resorption was not (p = 0.608).

CONCLUSION

The new technique resulted in significantly more bone gain than a conventional GBR technique. The rate of graft resorption during healing was stable regardless of the amount of grafted material.

Survival Rates of Dental Implants in Autogenous and Allogeneic Bone Blocks: A Systematic Review

Background and Objectives: Preliminary studies emphasize the similar performance of autogenous bone blocks (AUBBs) and allogeneic bone blocks (ALBBs) in pre-implant surgery; however, most of these studies include limited subjects or hold a low level of evidence. The purpose of this review is to test the hypothesis of indifferent implant survival rates (ISRs) in AUBB and ALBB and determine the impact of various material-, surgery- and patient-related confounders and predictors. Materials and Methods: The national library of medicine (MEDLINE), Excerpta Medica database (EMBASE) and Cochrane Central Register of Controlled Trials (CENTRAL) were screened for studies reporting the ISRs of implants placed in AUBB and ALBB with ≥10 participants followed for ≥12 months from January 1995 to November 2021. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed via several scoring tools, dependent on the study design. Means of sub-entities were presented as violin plots. Results: An electronic data search resulted in the identification of 9233 articles, of which 100 were included in the quantitative analysis. No significant difference (p = 0.54) was found between the ISR of AUBB (96.23 ± 5.27%; range: 75% to 100%; 2195 subjects, 6861 implants) and that of ALBB (97.66 ± 2.68%; range: 90.1% to 100%; 1202 subjects, 3434 implants). The ISR in AUBB was increased in blocks from intraoral as compared to extraoral donor sites (p = 0.0003), partially edentulous as compared to totally edentulous (p = 0.0002), as well as in patients younger than 45 as compared to those older (p = 0.044), cortical as compared to cortico-cancellous blocks (p = 0.005) and in delayed implantations within three months as compared to immediate implantations (p = 0.018). The ISR of ALBB was significantly increased in processed as compared to fresh-frozen ALBB (p = 0.004), but also in horizontal as compared to vertical augmentations (p = 0.009). Conclusions: The present findings widely emphasize the feasibility of achieving similar ISRs with AUBB and ALBB applied for pre-implant bone grafting. ISRs were negatively affected in sub-entities linked to more extensive augmentation procedures such as bone donor site and dentition status. The inclusion and pooling of literature with a low level of evidence, the absence of randomized controlled clinical trials (RCTs) comparing AUBB and ALBB and the limited count of comparative studies with short follow-ups increases the risk of bias and complicates data interpretation. Consequently, further long-term comparative studies are needed.

Lateral Alveolar Ridge Augmentation with an Autogenous Bone Block Graft Alone with or without Barrier Membrane Coverage: a Systematic Review and Meta-Analysis

Objectives

To test the hypothesis of no difference in implant treatment outcome following lateral alveolar ridge augmentation with autogenous bone block graft with or without barrier membrane coverage.

Material and Methods

PubMed (MEDLINE), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 8^th of February 2021 were included. Randomised controlled trials with an observation period longer than three months were included. Survival of implants and suprastructures were considered as primary outcomes measures, whereas peri-implant marginal bone loss, dimensional changes of the alveolar ridge, bone regeneration, patient-reported outcome measures, biological and mechanical complications were secondary outcome measures, as evaluated by descriptive statistics and meta-analysis including 95% confidence interval (CI).

Results

Electronic search and hand-searching resulted in 411 entries. Five randomised controlled trials characterised by low or high risk of bias fulfilled inclusion criteria. No statistically significant difference between the two treatment modalities was observed in any of the outcome measures. However, barrier membrane coverage was associated with a non-significant gain in alveolar ridge width of 0.5 mm (95% CI = -0.1 to 1.1) and diminished resorption of -0.9 mm (95% CI = -2.4 to 0.7) compared with no barrier membrane coverage.

Conclusions

Comparable implant treatment outcomes were revealed following lateral alveolar ridge augmentation with autogenous bone block graft alone with or without barrier membrane coverage. However, postoperative dimensional changes of the augmented seems to be diminished with the use of barrier membrane coverage as evaluated by two-dimensional linear measurements.

Primary bone augmentation leads to equally stable marginal tissue conditions comparing the use of xenograft blocks infused with BMP-2 and autogenous bone blocks: A 3D analysis after 3 years

Objectives

To test whether or not primary bone augmentation using xenograft blocks infused with BMP‐2 or autogenous bone blocks lead to similar results regarding the implant survival and 3D marginal soft tissue contours.

Methods

Twenty‐four patients with an insufficient ridge width for implant placement in need of primary augmentation were randomly assigned to either a block of deproteinized bovine bone mineral infused with rhBMP‐2 (BMP) or an intraorally harvested block of autogenous bone (ABB). At 4 months, 1–4 dental implants were placed in the regenerated area. After crown insertion and at 3 years, peri‐implant tissue parameters, two‐ and three‐dimensional radiographic parameters, and soft tissue contour changes were evaluated. Explorative mixed model analyses were performed. The level of significance was set at 5%.

Results

At the 3‐year follow‐up, 23 patients with 40 implants were evaluated. The implant survival rate was 100% in both groups. At baseline, the marginal hard tissue levels amounted to −0.4 ± 0.8 mm (mean ± standard deviation) in the BMP group and −0.7 ± 1.0 mm in the ABB group. At 3 years, these values were −0.2 ± 0.4 mm (BMP) and −0.6 ± 1.0 mm (ABB). At baseline, the thickness of the buccal hard tissue at the level of the implant shoulder measured 1.1 ± 1.1 mm (BMP) and 1.4 ± 1.0 mm (ABB). At 3 years, it measured 0.9 ± 0.9 mm (BMP) and 0.7 ± 0.6 mm (ABB).

Conclusions

The present study demonstrated excellent implant survival rates and stable marginal hard tissue levels in both augmentation groups, 3 years after crown insertion. In addition, the clinical stability of soft and hard tissues was demonstrated in both groups.

Horizontal Ridge Augmentation: A Comparison between Khoury and Urban Technique

PURPOSE

The objective of this systematic review was to evaluate and compare the clinical efficacy of horizontal alveolar ridge augmentation techniques described by Khoury and Urban.

METHODS

A systematic electronic search in the MEDLINE databases, SCOPUS, WOS, and the Cochrane Central Register of Controlled Trials (CENTRAL) as well as a manual search, were conducted independently by two reviewers up to July 2021.

RESULTS

Six studies met the pre-established inclusion criteria and were included in the descriptive analysis. Due to the heterogeneity found across the included studies, meta-analysis could not be performed. Horizontal bone gain was between 3.93 ± 0.9 mm and 5.02 ± 0.8 mm with the Khoury technique and between 3.9 ± 0.9 mm and 5.68 ± 1.42 mm with the Urban technique. Similar complication rates were reported in both groups: infection (7%), in the Khoury technique, and membrane exposure (3.2-13.6%), in the Urban technique, being the most frequent events.

CONCLUSIONS

Both techniques were found to be effective, in terms of clinical bone gain, for horizontal alveolar ridge gain. Nevertheless, available literature is limited, and there is a lack of comparative studies to better evaluate the results.

Peri-Implantitis: A Clinical Update on Prevalence and Surgical Treatment Outcomes

Dental implants may be considered a reliable routine procedure in clinical practice for the replacement of missing teeth. Results from long-term studies indicate that implant-supported dental prostheses constitute a predictable treatment method for the management of fully and partially edentulous patients. Implants and their restorations, however, are not free from biological complications. In fact, peri-implantitis, defined as progressive bone loss associated to clinical inflammation, is not a rare finding nowadays. This constitutes a concern for clinicians and patients given the negative impact on the quality of life and the sequelae originated by peri-implantitis lesions. The purpose of this narrative review is to report on the prevalence of peri-implantitis and to overview the indications, contraindications, complexity, predictability and effectiveness of the different surgical therapeutic modalities to manage this disorder.

Comparison of Success Rate of Dental Implants Placed in Autogenous Bone Graft Regenerated Areas and Pristine Bone

Autogenous bone grafting still has been considered as the "gold standard" and wildly used in the case of alveolar bone reconstruction. The aim of the present study is to evaluate the success rate of implants placed in autogenous block augmented ridges and implants placed in pristine bone (PB). This study included 113 patients. Fifty-three patients were treated with autogenous block grafts and particulate bone, after 6 months of healing implant placements were performed in autogenous bone augmented (ABA) areas. In 60 patients implant placement was performed, with no need for grafting and implants were placed into the PB. Follow-up data (pain, mobility, exudation from peri-implant space, success rate, marginal bone resorption) were collected after 5 years of prosthetic loading. The cumulative implant success rate at the 5-year examination was 92.45% for the ABA group and 85% for PB group. There were 3 failed implants in the ABA group and 3 in PB group. Average marginal bone loss was 1.47 mm on ABA group and 1.58 mm on PB group. No statistically significant differences for pain, exudation from peri-implant space, implant mobility, implant success, peri-implant bone loss parameters, and patient satisfaction level were found between groups. The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to the success rate of implants those placed in PB.

A clinical and radiographic study of implants placed in autogenous bone grafts covered by either a platelet-rich fibrin membrane or deproteinised bovine bone mineral and a collagen membrane: a pilot randomised controlled clinical trial with a 2-year follow-up

Purpose

To compare the survival and clinical performance of implants placed in sites previously augmented with autogenous bone grafts covered by either a platelet-rich fibrin (PRF) membrane (PRF group) or a standard procedure (gold standard) involving coverage of the autogenous bone graft with deproteinised bovine bone mineral and a resorbable collagen membrane (control group).

Methods

A total of 27 partially edentulous patients (test n = 14, control n = 13) with indication for staged lateral bone block augmentation and dental implant placement were included. Twenty-four months after crown placement (range: 14–32 months), patients were recalled for a final clinical and radiographic follow-up. Outcome measures were implant survival, implant crown survival, clinical parameters of the implant, peri-implant marginal bone level, marginal bone level of adjacent tooth surfaces, biological and technical complications and patient-related outcome measures.

Results

Two implants were lost in the control group (85% survival rate); none were lost in the PRF group (100% survival rate). None of the 26 initially placed implant crowns were lost, but one implant and therefore one implant crown were lost after 20 months. Consequently, the definitive implant crown survival was 92% (95% confidence interval (CI): 73–110%) in the control group and 100% in the PRF group. No statistical difference in implant survival rate (p = 0.13) or implant crown survival was seen between the groups (p = 0.28). The mean marginal bone level at the follow-up was 0.26 mm (95% CI: 0.01–0.50 mm) in the PRF group and 0.68 mm (95% CI: 0.41–0.96 mm) in the control group. The difference between the groups was − 0.43 mm (95% CI: − 0.80 to − 0.05 mm, p = 0.03), which was statistically significant (p = 0.03). Both groups demonstrated similar healthy peri-implant soft tissue values at the final follow-up.

Conclusion

Although the current study is based on a small sample of participants, the findings suggest that the methodology of the PRF and the control group approach can both be used for bone augmentation with a similar outcome. A significant, but clinically irrelevant, higher peri-implant marginal bone level was registered in the PRF group than in the control group. Patients in both groups were highly satisfied with the treatment.

Trial registration

ClinicalTrials.gov Identifier: NCT04350749. Registered 17 April 2020. Retrospectively registered.

MRI for the display of autologous onlay bone grafts during early healing-an experimental study

OBJECTIVES

Autologous bone grafts are the gold standard to augment deficient alveolar bone. Dimensional graft alterations during healing are not known as they are not accessible to radiography. Therefore, MRI was used to display autologous onlay bone grafts in vivo during early healing.

METHODS AND MATERIALS

Ten patients with alveolar bone atrophy and autologous onlay grafts were included. MRI was performed with a clinical MR system and an intraoral coil preoperatively (t0), 1 week (t1), 6 weeks (t2) and 12 weeks (t3) postoperatively, respectively. The graft volumes were assessed in MRI by manual segmentation by three examiners. Graft volumes for each time point were calculated and dimensional alteration was documented. Cortical and cancellous proportions of bone grafts were assessed. The intraobserver and interobserver variability were calculated. Statistical analysis was performed using a mixed linear regression model.

RESULTS

Autologous onlay bone grafts with cortical and cancellous properties were displayed in vivo in eight patients over 12 weeks. The fixation screws were visible as signal voids with a thin hyperintense fringe. The calculated volumes were between 0.12-0.74 cm³ (t1), 0.15-0.73 cm³ (t2), and 0.17-0.64 cm³ (t3). Median changes of bone graft volumes of -15% were observed. There was no significant difference between the examiners (p = 0.3).

CONCLUSIONS

MRI is eligible for the display and longitudinal observation of autologous onlay bone grafts. Image artifacts caused measurements deviations in some cases and minimized the precise assessment of graft volume. To the knowledge of the authors, this is the first study that used MRI for the longitudinal observation of autologous onlay bone grafts.

Alveolar ridge augmentation using the shell technique with allogeneic and autogenous bone plates in a split-mouth design-A retrospective case report from five patients

Atrophic alveolar ridges of five patients were augmented with allografts and autografts on opposite sites, followed by dental implantation. Both augmentation materials led to equivalent bone gains. Allografts did not compromise the clinical outcome.

Resorption of retromolar bone grafts after alveolar ridge augmentation-volumetric changes after 12 months assessed by CBCT analysis

In this pilot study, a volumetric analysis of retromolar onlay bone grafts over a period of 12 months was conducted, using repeated CBCT imaging combined with automated image registration.

Eleven patients being treated with 16 bone grafts taken from the retromolar area were examined by CBCT scanning prior to bone augmentation (T0), immediately after bone augmentation (T1) and after a healing time of 12 months after augmentation (T2). Graft volumes were measured at each time point after automated image registration of consecutive CBCT scans.

The mean volume of the augmented site was 372.2 ± 179.4 mm³. Resorption relative to the original augmented volume was 43.7% ± 19.0% after 12 months.

Three-dimensional graft resorption could be precisely depicted by the use of automated image registration for CBCT data over a period of 12 months and demonstrated extensive volumetric changes of bone grafts taken from the ascending ramus of the mandible.

Graft resorption and continuous bony remodeling of the grafted site before and after implant insertion have to be carefully considered by the clinician.

Trabecular structure and composition analysis of human autogenous bone donor sites using micro-computed tomography

OBJECTIVES

To evaluate the bone microstructure of autogenous graft bone in elderly people (mean age, 66 years), we compared the bone volume/total volume and bone mineral density of four donor sites that are commonly harvested for maxillofacial surgery and dental implant treatments, using X-ray micro-computed tomography.

METHODS

Eighteen Japanese cadavers were included in this study. Overall, 66 harvested bones (mandibular symphysis, mandibular ramus, ilium, and tibia) were studied. Micro-computed tomography scans of four sites were performed to analyze the trabecular structures, bone mineral density, and bone volume/total volume in these bones.

RESULTS

The mandibular symphysis bones showed the highest bone volume/total volume and bone mineral density at the four sites. There was a significant difference in the bone volume/total volume between the mandibular symphysis and tibia groups. There was also a significant difference in bone mineral density between the mandibular symphysis group and the ilium and tibia groups. In the three-dimensional observations, the structures of the mandibular trabecular were plate-type. The structures of the tibial bone were mixtures of plate- and rod-types. In the ilium, most trabecula were rod-shaped.

CONCLUSIONS

Mandibular symphysis and ramus had a higher bone volume/total volume and bone mineral density of the four sites and did not show regressive changes in our findings. Mandibular bone is the most suitable source of autogenous graft bone material because of its superior bone quality and quantity.

Radiographic changes in height and volume after lateral GBR procedures with different ratios of deproteinized bovine bone mineral and autogenous bone at different time points. An experimental study

OBJECTIVE

Estimate changes in augmentation height and volume after lateral guided bone regeneration (GBR) augmentation with different ratios of deproteinized bovine bone mineral (DBBM) and particulate autogenous bone (PAB) and autogenous bone block (ABB), at different time points.

MATERIAL AND METHODS

Twenty-four minipigs were randomly allocated into three healing periods. Lateral augmentation in 96 sites with standardized quantity of graft material was performed with different ratios of DBBM and PAB (50:50, 75:25, and 100:0) and ABB in combination with DBBM, covered by a collagen membrane. Changes in augmentation height and volume were assessed on CT volumes acquired 10, 20, and 30 weeks after surgery.

RESULTS

Reduction in bone augmentation height was as follows: 50:50-1.7 mm (-33.1%), 75:25-1.8 mm (-37.8%), 100:0-1.7 mm (-35.8%), and ABB - 0.2 mm (-3.7%), after 30 weeks. The augmentation height was significantly better preserved with ABB compared to 50:50, 75:25, and 100:0, while no significant difference was present among particulate grafts. No significant difference in volumetric reduction was found among 50:50, 75:25, 100:0 and ABB after 30 weeks, while 100:0 presented significant less reduction compared to 50:50, 75:25 and ABB after 10 and 20 weeks.

CONCLUSIONS

Augmentation height following GBR was better preserved with ABB covered with DBBM. Addition of PAB to DBBM did not affect the changes in height of the graft. The volumetric stability seems to be comparable for ABB covered by DBBM and all particulate grafts after 30 weeks. However, DBBM alone revealed significant less volume reduction in the early healing phase.

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.

Autogenous bone augmentation from the zygomatic alveolar crest: a volumetric retrospective analysis in the maxilla

BACKGROUND

Autogenous bone augmentation is the gold standard for the treatment of extended bone defects prior to implantation. Bone augmentation from the zygomatic crest is a valuable option with several advantages, but the current literature for this treatment is scant. The aim of this study was to evaluate the increase in bone volume after locoregional bone augmentation using autogenous bone from the zygomatic alveolar crest as well as the complications and success rate.

RESULTS

Analysis of the augmented bone volume in seven patients showed a maximum volume gain of 0.97 cm³. An average of 0.54 cm³ of autogenous bone (SD 0.24 cm³; median: 0.54 cm³) was augmented. Implantation following bone augmentation was possible in all cases. Complications occurred in three patients.

CONCLUSION

The zygomatic alveolar crest is a valuable donor site for autogenous alveolar onlay grafting in a locoregional area such as the maxillary front. Low donor site morbidity, good access, and its suitable convexity make it a beneficial choice for autogenous bone augmentation.

Wedge-Shaped Implants for Minimally Invasive Treatment of Narrow Ridges: A Multicenter Prospective Cohort Study

The present study aims to investigate clinical and patient-centered outcomes after the implant-supported rehabilitation of narrow ridges using a novel wedge-shaped implant. Forty-four patients were treated with the insertion of 59 tissue-level wedge implants (1.8 mm bucco-lingual width) in horizontally atrophic ridges (mean bone width 3.8 ± 0.4 mm). The main outcome measures were: implant stability quotient (ISQ), marginal bone loss (MBL) and patient morbidity. Fifty-eight implants were functioning satisfactorily after one year of loading (98.3% survival rate). ISQ values measured in the mesio-distal direction resulted significantly higher than those in the bucco-lingual direction at all time points (p < 0.001). Both mesio-distal and bucco-lingual ISQ values at 6-month follow-up resulted significantly higher than at 4-month follow-up (p < 0.001 for both). Mean MBL was 0.38 ± 0.48 mm at prosthesis delivery (6 months after implant insertion) and 0.60 ± 0.52 mm after one year of functional loading. The majority of patients reported slight discomfort related to the surgical procedure. Postoperative pain score was classified as mild pain on the day of surgery and the first postoperative day and no pain over the following five days. Within the limitations of the present study, the device investigated showed low morbidity and positive short-term clinical results in narrow ridges treatment.

Evaluation of deformation in the buccal lamellar bone with finite element analysis in alveolar ridge-splitting/expansion technique

PURPOSE

The aim of this study was to investigate deformation and stress distribution in the buccal lamellar bone via finite element analysis (FEA) in the application of alveolar ridge-splitting/expansion technique (ARST) in atrophic maxilla and mandible.

MATERIAL AND METHOD

Three-dimensional (3D) solid models of maxilla and mandible were formed using computer software, with an alveolar ridge thickness of 4 mm in the right first molar region. In both models, one horizontal and two releasing vertical osteotomies were made in the atrophic region. Vertical forces varying from 50 N to 1000 N were continuously applied on the midpoint of the horizontal osteotomy and then the axial and total deformation and von Mises stress distribution in the buccal lamellar bone was assessed by FEA.

RESULTS

The degrees of axial deformation and total deformation and the maximum von Mises stress value under a 50 N force were 0.22 mm, 0.23 mm, and 4.52 MPa in the maxillary buccal lamellar bone and were 0.04 mm, 0.06 mm, and 5.90 MPa in the mandibular buccal lamellar bone, respectively. Similarly, under a 1000 N force, the values were 4.44 mm, 4.75 mm, and 90.49 MPa in the maxillary buccal lamellar bone and were 0.96 mm, 1.1 mm, and 118.02 MPa in the mandibular buccal lamellar bone, respectively.

CONCLUSION

These findings implicate that the ARST used for implant placement or alveolar augmentation can be achieved with the application of lower amounts of force in the maxilla compared to the mandible. It was also revealed that in ARST, the maximum von Mises stress value was lower in the maxillary buccal lamellar bone than in the mandibular buccal lamellar bone. Based on these findings, we consider that the administration of ARST could be biomechanically more stable in the maxilla than in the mandible.

A Modified Ridge Splitting Technique Using Autogenous Bone Blocks-A Case Series

Background: Alveolar atrophy following tooth loss is a common limitation of rehabilitation with dental implant born prostheses. Ridge splitting is a well-documented surgical method to restore the width of the alveolar ridge prior to implant placement. The aim of this case series is to present a novel approach to ridge expansion using only autogenous bone blocks. Methods: Patients with Kennedy Class I. and II. mandibles with insufficient bone width were included in this study. Ridge splitting was carried out with the use of a piezoelectric surgery device by preparing osteotomies and after mobilization of the buccal cortical by placing an autologous bone block harvested from the retromolar region as a spacer between the buccal and lingual cortical plates. Block-grafts were stabilized by osteosynthesis screws. Implant placement was carried out after a 3-month healing period. A total of 13 implants were placed in seven augmented sites of six patients. Results: Upon re-entry, all sites healed uneventfully. Mean ridge width gain was 2.86 mm, range: 2.0–5.0 mm. Conclusions: Clinical results of our study show that the modified ridge splitting technique is a safe and predictable method to restore width of the alveolar ridge prior to implant placement.

Bone Augmentation Procedures in a Patient with Acromegaly

The objective of this clinical case is to evaluate if bone augmentation procedures can be successful in a patient with altered bone metabolism due to a systemic disease: acromegaly. Two guided bone regeneration procedures were made on the same patient: horizontal ridge augmentation with lateral wall approach sinus graft of the left maxilla and horizontal ridge augmentation of the front left maxilla. CBCT assessment of the new formed bone was made after a minimum of nine months and dental implants were placed. The results show that bone augmentation procedures can be successful in a patient with acromegaly, after pituitary adenoma removal, when autologous bone is not included in the grafting procedure.