Implant survival rates after maxillary sinus augmentation

Do patient and surgical factors predict postoperative discomfort in implant dentistry?

DATA SOURCES

The study utilized records from the Department of Oral Implantology at Wuhan University (May 2020 to April 2021). A total of 366 participants with missing teeth requiring implant-supported rehabilitation were included. Records detailed patient demographics, clinical procedures, and postoperative experiences. Data were collected through telephonic follow-ups and questionnaires assessing pain, anxiety, discomfort, and adverse events.

STUDY SELECTION

Participants were selected based on the need for dental implant placement and/or bone augmentation. Inclusion criteria included being over 18 years old, possessing basic communication skills, and providing consent. Patients with systemic diseases, acute oral infections, or contraindications to implant therapy were excluded. Secondary-stage surgeries and sites with prior augmentation or implant failure were also excluded.

DATA EXTRACTION AND SYNTHESIS

Variables such as age, gender, alcohol consumption, smoking status, periodontal status, surgical procedures, and postoperative complications were collected. Perception of pain, anxiety, and discomfort was measured using a numerical rating scale (NRS). Logistic regression identified predictors of discomfort severity and duration.

RESULTS

Most participants reported mild or no pain (78.7%) and anxiety (89.7%) during surgery. Discomfort decreased significantly over time, with 57.7% reporting discomfort on day 1, 36.1% on day 3, and 0% by day 14.

CONCLUSION

Alcohol consumption, pain perception during surgery, age, and bone augmentation procedures were key predictors of discomfort. Tailored care is recommended to enhance outcomes.

Biomechanical Analysis of Truncated Cone Implants for Maxillary Sinus Lift: An In Vitro Study on Polyurethane Laminas

This study aimed to evaluate the biomechanical performance of two truncated cone implant designs in maxillary sinus lift (MSL) procedures using polyurethane laminas. A total of 128 implants were used. Polyurethane laminas were divided into two groups based on thickness (1 and 3 mm) and two subgroups based on density (20 and 30 pounds per cubic foot, PCF). Each subgroup tested two implants (Sinus-plant and Sinus Lift Concept: SLC), resulting in 8 experimental conditions and 16 implants per condition. The insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ) were measured. SLC implants achieved significantly higher IT and RT across all tested conditions (p < 0.0001), reporting the highest values at the 30 PCF/3 mm lamina (IT: 34.09 ± 0.32 Ncm; RT: 32.15 ± 0.29 Ncm) and the lowest at the 20 PCF/1 mm lamina (IT: 11.86 ± 0.22 Ncm; RT: 10.28 ± 0.22 Ncm). Additionally, SLC implants achieved significantly higher ISQ values, ranging from around 61 to 48 ISQ. Notably, this difference was not significant at the 20 PCF/3 mm lamina, highlighting that bone density may play a more critical role than thickness for SLC implants. This study simulated the clinical condition of achieving primary stability even with extreme maxillary bone thickness. The findings indicate that while both implant designs can be utilized in MSL procedures, the SLC is particularly effective in scenarios with limited bone thickness and density, potentially allowing for simultaneous MSL, implant placement, and healing screw application.

Long-Term Clinical Outcomes of Transalveolar Maxillary Sinus Floor Elevation with Rotatory Instruments: An 8-Year Follow-Up Prospective Clinical Study

Background: Transalveolar sinus floor elevation (TSFE) is a surgical technique for the placement of dental implants in patients with reduced height of the maxillary posterior alveolar bone. This study aims to demonstrate the clinical outcomes of TSFE using the minimal invasive sinus elevation (MISE) technique in partially and totally edentulous maxillary patients. Methods: This prospective clinical study followed STROBE guidelines. TSFE was performed using the MISE technique with the simultaneous placement of implants. Dental implants were loaded at 6 months. Maxillary vertical bone gain was measured by CBCT, and marginal bone loss was assessed by periapical radiographs. Results: Ninety-one patients, with a mean age of 62.1 ± 11.8 years, were treated with TSFE and the placement of 107 implants, with a mean follow-up of 96.2 ± 11.7 months. An increase of 4.3 ± 0.4 mm in bone height was achieved, with a dental implant cumulative survival rate of 97.2%. Peri-implantitis was observed in 9.3% of implants, and membrane perforation occurred in 7.7% of cases. Technical complications were noted in 5.5% of patients. Conclusions: Within the limitations of this clinical study, it can be concluded that the MISE technique is a successful protocol for the placement of implants in the posterior maxilla with reduced height of the alveolar ridge, with a rate of biological and prosthetic complications below 10% over an average follow-up period of 8 years.

Use of autologous micrografts associated with xenogeneic anorganic bone in vertical bone augmentation procedures with Barbell Technique®

INTRODUCTION

Bidirectional vertical ridge augmentation in the posterior maxilla is very challenging.

PURPOSE

To evaluate the regenerative potential of micrografts, derived from periosteum or bone tissue, added to an anorganic xenograft in vertical reconstruction of the posterior maxilla, by a prospective, controlled study.

MATERIALS AND METHODS

After clinical selection and the analysis of CBCT scans, 24 posterior maxillary sites, in 19 patients, were treated by using Barbell Technique®. Sites requiring both inlay and onlay reconstruction were enrolled in the study. In the Control Group (CG, n = 8), a xenograft was used in the inlay site and for the onlay site, a 1:1 mix of xenograft and an autograft was used. In Test Group 1 (TG1, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from periosteum. In Test Group 2 (TG2, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from bone. Six months after the procedures, CBCT scans were obtained, and bone biopsy samples were harvested during implant placement surgery. The bone specimens were analyzed histomorphometrically, by measuring the percentages of vital mineralized tissue (VMT), non vital mineralized tissue (NVMT) and non mineralized tissue (NMT). Immunohistochemically, the levels of VEGF were categorized by a score approach.

RESULTS

Histomorphometric analysis revealed, for the inlay grafts, no significant difference among the groups for VMT, NVMT and NMT. However, for onlay grafts, CG achieved a higher amount of VMT in comparison with TG2, and the opposite occurred for NMT values. In this regard, no statistical difference was observed between CG and TG1. Concerning immunohistochemistry, the VEGF values for CG and TG1 were slightly higher than those obtained by TG2 for both inlay and onlay grafts, but without statistical significance. CBCT analysis showed a similar level of gain for all groups, for both inlay and onlay bone augmentation sites. Clinically, one implant (in CG) within a total of 50 implants installed, had early failure and was replaced after 3 months. All patients received implant supported prosthesis.

CONCLUSION

This study indicated that the clinical use of micrograft derived from periosteum may have some potential to increase bone formation in onlay reconstructions, unlike the micrograft derived from bone tissue.

The comparison of visibility of the maxillary sinus septa between cone-beam computed tomography scans and panoramic radiograph images as dependent on the cortical bone thickness: a retrospective comparative study

PURPOSE

To analyze the visibility of the maxillary sinus septa (MSS) in panoramic radiography (PR) versus cone beam computed tomography (CBCT) and to investigate whether the buccal cortical bone thickness (BT) or the septa dimensions influence their visibility.

METHODS

Corresponding PR and CBCT images of 355 patients were selected and examined for MSS visibility. The septa dimensions (width, height, depth) and the BT were measured. Results were analysed statistically.

RESULTS

Comparing the corresponding regions on CBCT and PR, 170 MSS were identified; however, only 106 of these were also visible using PR. The MSS visibility was significantly higher on CBCT versus PR images (P1: p = 0.039, P2: p = 0.015, M1: p = 0.041, M2: p = 0.017, M3: p = 0.000), except region C (p = 0.625). Regarding the measurements of MSS dimensions, only the height in region M1 (p = 0.013) and the width in region P2 (p = 0.034) were significantly more visible on CBCT. The BT in the area of the MSS was found to have a marginal influence on its visibility on the PR images only in regions M3 and M1 (M3: p = 0.043, M1: p = 0.047). In terms of MSS visibility based on the dimensions, significance was found for all three influencing variables only in region P2 (width; p = 0.041, height; p = 0.001, depth; p = 0.007). There were only isolated cases of further significance: M3 for width (p = 0.043), M2 for height (p = 0.024), and P1 for depth (p = 0.034), no further significance was noted.

CONCLUSION

MSS visibility appears significantly higher on CBCT versus PR images. It is concluded that the septa dimensions and BT can influence MSS visibility on PR images just in certain regions.

Radiographic assessment of maxillary sinus membrane and lateral wall thickness using cone-beam CT in different facial types in southwestern Saudi Arabia

The anatomy of the edentulous posterior maxilla and maxillary sinus possess unique challenges in implant dentistry. The purpose of this study was to assess maxillary sinus membrane thickness (MT) and lateral wall thickness (LWT) in different facial index profiles and to describe the clinical implications. A retrospective image analysis of 75 CBCT scans was done, which yielded a total of 150 sinus images. The facial index was calculated as per the formula given in the text and grouped as euryprosopic, mesoprosopic and leptoprosopic. The images obtained were of 36 women (48%) and 39 men (52%), with maximum subjects in 30-39 years age group. MT and LWT were measured at three different points on the radiograph at every 3mm from the base of the sinus floor in premolar and molar regions of each image. Results showed females had significant differences from males in LWT in both premolar and molar regions (p = 0.018 and 0.032 respectively). Subjects in 40-49 years of age had significant differences (p = 0.021) in MT in premolar region only. Also, difference in MT in premolar and molar regions were also statistically significant. Lastly, the present study did not find any statistically significant difference in MT and LWT in all three facial indices groups. It can be concluded that different facial indices have no positive correlation with maxillary sinus membrane thickness and lateral wall thickness. Hence, surgical complications are avoidable with proper detailed knowledge and appropriate identification of the anatomic structures characteristic to the maxillary sinus.

Do dental implants installed in different types of bone (I, II, III, IV) have different success rates? A systematic review and meta-analysis

Purpose

The objective of this systematic review and meta-analysis was to evaluate the survival rate of implants installed in bone type IV (Lekholm and Zarb, 1995) compared to that of implants installed in bone types I, II, and III.

Material and methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) and was registered in the PROSPERO International Database of Systematic Reviews (CRD42021229775). The PubMed/MEDLINE, Scopus, and Cochrane databases were searched through July 2021. The PICO question was: "Dental implants installed in type IV bone have a lower success rate when compared to implants installed in type I bone, II and III?". The established inclusion criteria were: 1) controlled and randomized clinical trials (RCT), 2) prospective and retrospective studies with at least 10 participants with dental implants, and 3) patients with dental implants installed in bone tissue types I, II, III, and IV (Lekholm and Zarb, 1985). The minimum followup duration was 1 year.

Results

After searching the identified databases, 117 articles were selected for full reading and 68 were excluded. Thus, 49 studies were included for qualitative and quantitative analyses. The total number of participants included was 12,056, with a mean age of 41.56 years and 29,905 implants installed. Bone types I, II, and III exhibit a lower implant failure rate when compared to bone type IV.

Conclusion

Dental implants installed in bone types I, II, and III showed significantly higher survival rates than those installed in type IV. The bone type I success rate was not significantly different than that of type II; however, the success rate of bone type I and II was higher than that of type III.

Does Collagen Membrane Coverage Offer any Advantage for Lateral Window Sinus Augmentation? A Histologic and Histomorphometric Analysis

Background

We aimed to determine whether collagen membrane coverage in maxillary sinus floor elevation surgery, provides an advantage regarding bone regeneration.

Methods

This randomized clinical trial included all healthy adults presented for dental implant placement in the posterior edentulous maxilla at the Maxillofacial Surgery Department of Mashhad Dental School, Mashhad, Iran from 2021-2022. Participants were candidates for sinus floor elevation surgery. Patients were randomly allocated to control (with membrane) and test (without membrane) groups. Surgery was performed through the lateral window technique and using allograft particles. According to the assigned study group; either a collagen membrane was placed over the osteotomy window or it was left uncovered. Six months after surgery when patients were recalled for implant placement, a bone specimen was obtained and sent for histologic and histomorphometric analysis. The predictor variable was the use of collagenous membrane and the outcome variables were the amount of newly formed bone, native bone, and connective tissue.

Results

A total of 30 consecutive patients, with a mean age of 46.33±7.25 years completed the study. Histomorphometric measurements, six months after augmentation revealed that the mean area of connective tissue was significantly less in the group with membrane coverage (P=0.015). The area of newly formed bone was significantly greater in sites covered with a collagen membrane compared to grafted but uncovered sites; (P <0.001).

Conclusion

Covering the lateral osteotomy window with a bioabsorbable collagenous membrane is able to significantly enhance vital bone formation and decrease connective tissue proliferation.

Osteogenic Effect of a Bioactive Calcium Alkali Phosphate Bone Substitute in Humans

(1) Background: The desire to avoid autograft harvesting in implant dentistry has prompted an ever-increasing quest for bioceramic bone substitutes, which stimulate osteogenesis while resorbing in a timely fashion. Consequently, a highly bioactive silicon containing calcium alkali orthophosphate (Si-CAP) material was created, which previously was shown to induce greater bone cell maturation and bone neo-formation than β-tricalcium phosphate (β-TCP) in vivo as well as in vitro. Our study tested the hypothesis that the enhanced effect on bone cell function in vitro and in sheep in vivo would lead to more copious bone neoformation in patients following sinus floor augmentation (SFA) employing Si-CAP when compared to β-TCP. (2) Methods: The effects of Si-CAP on osteogenesis and Si-CAP resorbability were evaluated in biopsies harvested from 38 patients six months after SFA in comparison to β-TCP employing undecalcified histology, histomorphometry, and immunohistochemical analysis of osteogenic marker expression. (3) Results: Si-CAP as well as β-TCP supported matrix mineralization and bone formation. Apically furthest away from the original bone tissue, Si-CAP induced significantly higher bone formation, bone-bonding (bone-bioceramic contact), and granule resorption than β-TCP. This was in conjunction with a higher expression of osteogenic markers. (4) Conclusions: Si-CAP induced higher and more advanced bone formation and resorbability than β-TCP, while β-TCP's remarkable osteoconductivity has been widely demonstrated. Hence, Si-CAP constitutes a well-suited bioactive graft choice for SFA in the clinical arena.

Surgical and prosthetic rehabilitation of siblings with Witkop tooth and nail syndrome using zygomatic implants: a familial case series of 3 patients with up to 15-year follow-up

Witkop tooth and nail syndrome is a rare, autosomal dominant type of ectodermal dysplasia that can have significant effects on dentition, including hypoplastic and malformed dentition and significantly atrophic maxillas. Endosseous implants have become one possible solution to replace missing teeth, although their use in areas where bone is sparse becomes challenging. Due to the severe atrophy of the maxillary alveolus, extensive preprosthetic surgeries including orthognathic surgery, extensive bone grafting, and sinus floor augmentations have been recommended prior to placement of endosseous dental implants. Although this treatment has shown favorable outcomes, it requires multiple surgical procedures, contributing to a prolonged treatment course and increased morbidity. An alternative treatment of atrophic maxillas in patients with ectodermal dysplasia includes the use of zygomatic implants. This familial case series discusses 3 siblings, all previously diagnosed with Witkop Syndrome, who underwent comprehensive preprosthetic surgery and prosthetic rehabilitation using zygomatic implants with a follow-up period up to 15 years.

Maxillary Sinus Lift Procedures: An Overview of Current Techniques, Presurgical Evaluation, and Complications

A maxillary sinus lift procedure is indicated if a dental implant needs to be placed in the posterior maxilla with limited bone available to accommodate a dental implant. Both open and closed sinus lifting procedures are reliable approaches for increasing the bone volume needed to support proper implant positioning. However, these methods can lead to several complications. In addition to the general complications commonly linked to oral surgery, such as swelling or hematoma, the primary complication in open sinus lifting is typically the perforation of the Schneiderian membrane during osteotomy. Detailed and extensive presurgical evaluation is crucial to minimize such complications. The objective of this study was to delineate contemporary trends in sinus lift surgery, with a specific emphasis on different techniques of sinus lift procedure, anatomical and surgical factors, presurgical evaluation, bone grafting, and the practical implications of these factors in implant dentistry cases involving a deficient posterior maxilla. In conclusion, while both osteotome and lateral window techniques can assist clinicians in addressing the complexities of implant placement in a deficient posterior maxilla, bone height before implantation remains a critical factor in determining the success and longevity of implants.

Comparative diagnosis of the alveolar antral artery canal in the lateral maxillary sinus wall in corresponding panoramic radiography and cone-beam computed tomography

PURPOSE

Sinus lift operations are a tried and tested means of providing adequate implant prosthetics to patients with compromised jawbones. Knowledge of the arterial supply of the maxillary sinus region is essential for surgical treatment in this area. The aim of the present comparative study was to determine whether alveolar antral artery (AAA) canal can be diagnosed both in corresponding panoramic radiography (PR) and cone-beam computed tomography (CBCT).

METHODS

A total of 335 patients with 635 sites and corresponding maxillary sinus in both PR and CBCT were selected and examined for AAA canal visibility.

RESULTS

The visibility of the AAA canal was significantly higher in CBCT than in PR. A total of 154 (46.0%) AAA canals could be identified in the maxillary sinus on the right. However, only four (1.2%) of these were also visible in PR. The detected values of the AAA canals in the maxillary sinus on the left in the PR and CBCT images were similar to those of the right. While 164 AAA canals (49%) were observed in CBCT images, only 1 (0.3%) was identifiable in PR.

CONCLUSIONS

The results show that CBCT can be recommended for visualising the AAA canal when surgically planning sinus augmentation procedures.

Residual Bone Height and New Bone Formation after Maxillary Sinus Augmentation Procedure Using Biomaterials: A Network Meta-Analysis of Clinical Trials

BACKGROUND

Different factors may affect new bone formation following maxillary sinus floor augmentation for the rehabilitation of posterior edentulous maxilla. The purpose of this study was to determine the influence of residual bone height (RBH) on new bone formation after lateral sinus augmentation utilizing different biomaterials, through a network meta-analysis (NMA).

METHODS

PUBMED, Scopus, and Web of Science electronic databases were searched until 31 December 2022 to obtain relevant articles. A hand search was also conducted. Randomised controlled studies on maxillary sinus augmentation comparing different grafting materials in patients with atrophic posterior maxilla, in need of prosthetic rehabilitation, were included. The risk of bias was assessed following the guidelines of the Cochrane Collaboration. The primary outcome was new bone formation (NBF), assessed histomorphometrically. The statistical analysis was performed by splitting the data according to RBH (<4 mm and ≥4 mm).

RESULTS

A total of 67 studies were eligible for conducting NMA. Overall, in the included studies, 1955 patients were treated and 2405 sinus augmentation procedures were performed. The biomaterials used were grouped into: autogenous bone (Auto), xenografts (XG), allografts (AG), alloplasts (AP), bioactive agents (Bio), hyaluronic acid (HA), and combinations of these. An inconsistency factor (IF) seen in the entire loop of the XG, AP, and Bio+AP was found to be statistically significant. The highest-ranked biomaterials for the <4 mm RBH outcome were XG+AG, XG+AP, and Auto. Similarly, the surface under the cumulative ranking curve (SUCRA) of biomaterials for ≥4 mm RBH was Auto, Bio+XG, and XG+Auto.

CONCLUSION

There is no grafting biomaterial that is consistently performing better than others. The performance of the materials in terms of NBF may depend on the RBH. While choosing a biomaterial, practitioners should consider both patient-specific aspects and sinus clinical characteristics.

Sinus Augmentation Using Mineralized Bone Allografts: A 6-Month Histological and Histomorphometric Analysis

Purpose

The aim of this study was to evaluate, after a six-month healing period, the histological and histomorphometric results of mineralized bone allograft used in lateral sinus augmentation procedures.

Materials and Methods

Twenty-one pneumatized maxillary sinuses with residual bone height ≤ 4 mm were grafted with a mixture of 1/1 cortical and cancellous mineralized bone allograft using lateral sinus floor elevation. Six months later, during implant placement, a core biopsy was retrieved for histological and histomorphometric evaluation.

Results

Biopsies showed mature cancellous bone with no signs of acute or chronic inflammatory reactions. Higher magnification revealed new lamellar bone, active osteocytes and normal lamellar arrangement around Haversian canals interspersed with osteocytes in lacunae. At grafted bone periphery, a high concentration of osteoblastic/osteoclastic couple was noted, indicating active bone remodeling. Histomorphometric evaluation revealed an average vital bone content of 30.32% (25.00-44.00%), and a percentage of residual non-vital bone of 18.06% (14.05-25.00%).

Conclusions

Histological and histomorphometric evaluation indicated that the mixture of 1 to 1 cortical and cancellous mineralized bone allograft promoted de-novo bone formation and can be predictably used for sinus augmentation procedures.

Bone-Regenerative Ability of Platelet-Rich Plasma Following Sinus Augmentation with Anorganic Bovine Bone: A Systematic Review with Meta-Analysis

BACKGROUND

The objective of this systematic review is to assess the effect of the adjuvant use of platelet-rich plasma (PRP) and its type on new bone formation by anorganic bovine bone during maxillary sinus floor augmentation procedure.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, and Ovid databases were searched for relevant studies published up to 16 September 2021. Randomized clinical trials (RCTs) and non-randomized controlled clinical trials (CCTs) that reported data on the new bone formation (measured by histomorphometric analysis) were considered. Risk of bias and quality assessment of included studies were evaluated following the Cochrane Handbook for Systematic Reviews of Interventions and the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool. Strength of evidence was assessed following the approach of the Agency for Healthcare Research and Quality (AHRQ) through its evidence-based practice center (AHRQ EPC). The meta-analysis was based on the primary outcome of newly formed bone, for which the standard mean difference was calculated.

RESULTS

After the application of eligibility criteria, six clinical trials (three RCTs and three CCTs) covering 85 maxillary sinus floor elevation procedures were included. The pooled new bone formation value for PRP was 1.67 (95% CI: -0.15 to 3.49; I2: 86%), indicating the absence of significant effect. Plasma rich in growth factors (PRGF) was the pure PRP tested in five of the included studies. When sub-group (type of PRP) meta-analysis was performed, significantly higher new bone formation was observed in the PRGF group [2.85 (95% CI: 0.07 to 5.64; I2: 88%)] in comparison to the control group.

CONCLUSIONS

A beneficial effect on new bone formation after maxillary sinus floor elevation can be obtained when anorganic bovine bone is mixed with PRGF.

Characterization of Dental Pulp Stem Cells Response to Bone Substitutes Biomaterials in Dentistry

Bone substitute biomaterials (BSBs) represent a promising alternative to bone autografts, due to their biocompatibility, osteoconduction, slow resorption rates, and the ability to define and maintain volume for bone gain in dentistry. Many biomaterials are tailored to provide structural and biological support for bone regeneration, and allow the migration of bone-forming cells into the bone defect. Neural crest-derived stem cells isolated from human dental pulp (hDPSCs) represent a suitable stem cell source to study the biological effects of BSBs on osteoprogenitor cells involved in the physiological bone regenerative processes. This study aimed to evaluate how three different BSBs affect the stem cell properties, osteogenic differentiation, and inflammatory properties of hDPSCs. Our data highlight that BSBs do not alter cell proliferation and stemness markers expression, nor induce any inflammatory responses. Bone metabolism data show that hDPSCs exposed to the three BSBs distinctively secrete the factors supporting osteoblast activity and osteoclast activity. Our data indicate that (i) hDPSCs are a suitable stem cell source to study the effects of BSBs, and that (ii) the formulation of BSBs may condition the biological properties of stem cells, suggesting their versatile suitability to different dentistry applications.

Analysis of acute sinusitis-related early failed implant surface: a combined histological, electron microscopy, and X-ray spectroscopy approach

BACKGROUND

Even though dental implants are a reliable choice for dental rehabilitation, implant failures due to various etiologies have been reported. Early implant failures account for 2 to 6% of installed implants and are reported to have a higher rate than late failures, regardless of loading time. We herein report three cases of acute sinusitis and early implant failure with implants that failed within 1 month after installation. The aim of this study was to evaluate the surface properties of early failed implants and peri-implant tissue to determine the early osseointegration pattern in acute sinusitis-related failed implants as well as the possible role of surface contamination in the failure of osseointegration.

RESULTS

A combined histological, electron microscopy, and X-ray spectroscopy approach was used to characterize the surface of non-osseointegrated titanium implants and the surrounding biological tissues. Morphologic scanning electron microscopy revealed a heterogeneous surface and irregular osseointegration. The implant surface was covered mostly by carbon- and oxygen-rich organic matter. Energy-dispersive X-ray spectroscopy surface analysis of three implants showed the incorporation of some contaminants in both the upper and apical regions. Carbon, nitrogen, sodium, silicon, chlorine, sulfur, gold, and zirconium were detected on the surface of one or more failed implants. Fibrosis, lymphocytic, and macrophage infiltrates and a high activation of osteoclasts surrounding the bone graft particles were detected in the surrounding tissues.

CONCLUSIONS

The etiology and mechanism of early implant failure, especially in sinus-related cases, as well as the proper management interventions to minimize the rate of early implant failures, are of great concern. No matter how confident and accurate the surgeon's operation, there may be unknown errors in the whole procedure that no one knows about. Rather than errors related to the implant surface, it is expected that there were invisible problems during the evaluation of the patient's own unique sinus mucosal inflammation or the operator's own procedure. Furthermore, well-designed researches are necessary to reveal the effect of material-related factors on acute sinus complication and early implant failure.

Radiographic Analysis of Graft Dimensional Changes in Transcrestal Maxillary Sinus Augmentation: A Retrospective Study

Background. The maxillary sinus lift is a popular and predictable technique associated with implant-supported rehabilitation of the severely atrophic maxilla. The aim of the present retrospective study was to investigate the effectiveness of transcrestal maxillary sinus augmentation and the graft resorption pattern using different heterologous bone substitutes. Methods. A total of 75 sinus-grafting procedures were performed and 89 implants were placed in 66 patients, 24 males and 42 females, with mean age 67.9 ± 10.64 years (range 43−84 years). Nineteen subjects were smokers. The mean follow-up period was 93.33 ± 54.71 months (range 14−240 months). Clinical and radiographical evaluations were performed. Graft height and width were measured at baseline and at the latest follow-up. Results. Mesiodistal and vertical resorption averaged 9.3 ± 20.7% (standard deviation), and 5.04 ± 9.9% of the postoperative size, respectively, considering the graft as the unit. Linear regression analysis showed that graft resorption in both the vertical and the mesiodistal dimension is independent of the follow-up time. Conversely, there was a trend for greater resorption when increasing the postoperative graft size, in both vertical (p = 0.001) and horizontal (p = 0.007) dimensions. When grouping the dimensional changes by graft particle size (only small (<300 μm) particles, combination of small and medium (>500 μm)/large (>1000 μm) particles, and only medium/large particles), there was a trend for greater resorption associated with smaller particles, but it was not significant; neither in the mesiodistal nor in the vertical dimension (p = 0.17 and p = 0.25, respectively). No implant was lost during the observation period. In conclusion, the transcrestal technique for maxillary sinus augmentation documented a high level of predictability. The low clinical morbidity and the contextual dental implant positioning is clinically useful in relation to a significant reduction of the time required for implant restoration, a consistent decrease of the number of surgical phases, and a cost-effectiveness approach for the rehabilitation. The graft resorption pattern in all cases was compatible with persistent implant protection and support.

Sinus Lift Associated with Leucocyte-Platelet-Rich Fibrin (Second Generation) for Bone Gain: A Systematic Review

The purpose of this systematic review was to analyze sinus lifting procedures and to compare the efficiency of this treatment associated with the second generation of platelet-rich fibrin related to its effects on bone gain and to clarify the regenerative efficacy in sinus lift procedure, whether alone or as a coadjutant to other bone graft materials. The PICOT question was, “In clinical studies with patients needing a maxillary sinus lift (P), does the use of PRF either alone (I) or in conjunction with other biomaterials (C) improve the clinical outcome associated with bone gain and density (O), with at least three months of follow-up (T)?” An electronic search was conducted in the MEDLINE (PubMed), Science Direct, and Scopus databases through a search strategy. A total of 443 articles were obtained from the electronic database search. Sixteen articles met all criteria and were included in this review. Within the limitation of this study and interpreting the results carefully, it was suggested that a higher risk for implant failure after a sinus elevation might be seen in patients with residual bone ≤4 mm, and PRF application was effective, suggesting reducing the time needed for new bone formation.

Oral health-related quality of life and satisfaction in edentulous patients rehabilitated with implant-supported full dentures all-on-four concept: a systematic review

OBJECTIVE

Address oral health-related quality of life (OHRQoL) and patient satisfaction rehabilitated by the all-on-four concept as the primary outcome.

MATERIAL AND METHODS

A search was performed in the PubMed/MEDLINE, Web of Science, and Cochrane databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria (PRISMA). The PICO question was used to address the following specific question: "What is the level of oral health-related quality of life and satisfaction in edentulous patients and with atrophic jaws who received dental implants for full-arch implant-supported restorations following the all-on-four in the mandible or maxilla?"

RESULTS

Eleven studies including 693 patients aged 55 to 71 years were selected. The shortest follow-up period was 3 months and the longest, 7 years. Regarding the OHRQoL assessment method and patient satisfaction, the oral health impact profile (OHIP) and the visual analog scale (VAS) were the most used.

CONCLUSION

OHRQoL and satisfaction in patients whose rehabilitation was based on the all-on-four concept were high. However, the current evidence is still limited by the quality of the available studies, making long-term randomized studies necessary to establish the real effectiveness of this surgical-prosthetic approach.

CLINICAL RELEVANCE

Carefully analyze the aspects related to satisfaction and oral health-related quality of life of rehabilitated patients with implant-supported total prostheses made according to the all-on-four concept, aiming to achieve success through procedures with greater predictability and less complexity, as these are directly associated with recovery oral health of edentulous individuals with less morbidity and minimized costs.

Transcrestal sinus augmentation with simultaneous implant placement in 1 to 2 mm residual alveolar bone: a case report

An abstract is not required.

Energy-Dispersive X-ray Spectroscopic Investigation of Failed Dental Implants Associated with Odontogenic Maxillary Sinusitis

The failed dental implant associated with maxillary sinusitis is a multifactorial phenomenon and should be investigated thoroughly. The inflammatory process induced by accumulated biofilm and wear debris may increase mucous secretion and mucous thickening, which finally may lead to severe complications such as maxillary sinusitis. The inflammatory cytokines might compromise the long-term osseointegration of the related implant. In this study, implants retrieved from three patients who experienced implant failure relating to maxillary sinusitis were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy. SEM analysis of the implant apical region revealed a less-compact bone structure, indicating the high bone turnover due to an inflammatory process. The ratio of calcium (Ca) and phosphorus (P) was negligible in all specimens. Detection of fluorine (F), sodium (Na), silicon (Si), gold (Au), aluminum (Al), and magnesium (Mg) confirmed the contamination. The selected cases presented different biological aspects that might play the central role in the failed dental implants associated with maxillary sinusitis: the contamination of potentially toxic elements, microorganism infection, and long perforation of implant apex into the sinus. Each of the above phenomena needs to be confirmed with further clinical study with a larger number of failed implants and accompanying tissue samples.

Can Male Patient's Age Affect the Cortical Bone Thickness of Jawbone for Dental Implant Placement? A Cohort Study

Dental implants are among the most common treatments for missing teeth. The thickness of the crestal cortical bone at the potential dental implant site is a critical factor affecting the success rate of dental implant surgery. However, previous studies have predominantly focused on female patients, who are at a high risk of osteoporosis, for the discussion of bone quality and quantity at the dental implant site. This study aimed to investigate the effect of male patients’ age on the crestal cortical bone of the jaw at the dental implant site by using dental cone-beam computed tomography (CBCT). This study performed dental CBCT on 84 male patients of various ages to obtain tomograms of 288 dental implant sites at the jawbone (41 sites in the anterior maxilla, 95 in the posterior maxilla, 59 in the anterior mandible, and 93 in the posterior mandible) for measuring the cortical bone thickness. A one-way analysis of variance and Scheffe’s test were performed on the measurement results to compare the cortical bone thickness at implant sites in the four jaw areas. The correlation between male patient age and cortical bone thickness at the dental implant site was determined. The four jaw areas in order of the cortical bone thickness were as follows: posterior mandible (1.07 ± 0.44 mm), anterior mandible (0.99 ± 0.30 mm), anterior maxilla (0.82 ± 0.32 mm), and posterior maxilla (0.71 ± 0.27 mm). Apart from dental implant sites in the anterior and posterior mandibles, no significant correlation was observed between male patients’ age and the cortical bone thickness at the dental implant site.

Relative performance of various biomaterials used for maxillary sinus augmentation: A Bayesian network meta-analysis

OBJECTIVES

To assess the histomorphometric outcomes obtained in randomized clinical trials (RCTs) with different biomaterials used for maxillary sinus augmentation (MSA).

MATERIALS AND METHODS

A search of the existing medical literature until October 1, 2019, was performed. Inclusion criteria were (a) RCTs assessing a two-stage MSA from the lateral approach using autologous bone or biomaterials for grafting and (b) reported histomorphometric outcomes based on crestal bone core biopsy samples. The Bayesian method was used to perform pairwise meta-analyses and network meta-analysis (NMA). The primary outcome, the new bone percentage (NB %), was calculated as mean differences with 95% credible intervals. The interventions were ranked by their posterior probability by calculating the surface under the cumulative ranking curve values.

RESULTS

Thirty-four RCTs (842 MSAs) were included in the analysis with a normal healing period (5-8 months). All comparisons were presented in a league table. On the basis of the ranking probability, the most effective bone grafting material for NB% was bovine xenograft + bone marrow concentrate (BMC) (81%), followed by bovine xenograft + platelet-rich plasma (PRP) (77%), bioactive glass ceramic + autologous bone 1:1 (70%), nanocrystalline hydroxyapatite in silica gel (70%), and bioactive glass ceramic (70%). Autologous bone graft alone took the twelfth position with 57%.

CONCLUSION

Within the limitations of the present NMA, the analysis did not confirm autologous bone alone as the gold standard for MSA and showed superiority of composite grafts such as bovine xenograft + BMC after 5-8 months of healing.

The impact of anatomic, patient and surgical factors on membrane perforation during lateral wall sinus floor elevation

OBJECTIVES

This retrospective study aimed to evaluate the influence of anatomical, patient and surgical factors on the occurrence of membrane perforation (MP) during lateral window sinus floor elevation (LWSFE).

MATERIAL AND METHODS

A review of LWSFE patient records between 2014 and 2019 accounted for MP occurrence, window surface area (WSA), intravenous sedation use, osteotomy instrument type and clinician experience. Preoperative cone beam computed tomography (CBCT) scans were analyzed for lateral wall thickness (LWT), LFM and LAM angles formed between lateral and medial walls at the floor and anterior wall, respectively, sinus width at 5-, 10- and 15-mm (LM-5, LM-10 and LM-15) from the floor, residual bone height (RBH), sinus pathologies, septa and arterial anastomoses. The generalized estimating equation (GEE) approach with a sandwich variance-covariance estimator was used to evaluate the associations with MP.

RESULTS

MP occurred in 25.74% of 202 LWSFE procedures (166 patients). Mean 1.6 mm-LWT, 3.2 mm-RBH, 95°-LFM, 75.5°-LAM, 12 mm-LM-5, 20.79% septa, 16.83% arterial anastomosis, 37.62% sinus pathology and 29.21% intravenous sedations, 85.24% WSA ≥ 40 mm² and 57% >10 procedures/clinician were reported. Greater MP rates were encountered as follows: 38.3% (LWT ≥ 1.5 mm), 38% (LFM < 90°), 59.6% (LAM < 70°), 45.4% (LM-5 < 10 mm) and 36.4% (WSA ranged > 80 mm² ), with statistically significant associations with all these outcomes (p < .05). The presence of pathologies was also associated with MP (p = .013). Associations between MP and the presence of septa and arterial anastomoses, age/gender, right/left sinus, RBH, clinician's experience, instrument type and intravenous sedation use could not be demonstrated.

CONCLUSIONS

MP is significantly associated with thicker lateral walls, narrower sinuses, larger windows and existing sinus pathology.

The rehabilitation of posterior atrophic maxilla by using the graftless option of short implant versus conventional long implant with sinus graft: A systematic review and meta-analysis of randomized controlled clinical trial

Aim

The purpose of systematic review and meta-analysis was to compare the efficacy of short implant versus conventional long implant with sinus graft in patients rehabilitated for posterior atrophic maxilla.

Setting and Design

Systematic review and meta analysis.

Materials and Methods

Electronic searches were conducted in Pub Med, Embase, and Medline with supplemented by manual search up to December 2019. The randomized controlled trial (RCTs) comparing short implant (<8.5 mm) and long implant (>8.5 mm) with sinus graft were included. (Prospero CRD42020186972).

Statistical Analysis Used

Random-effect model, fixed-effect model, A funnel plot and the Egger's test.

Results

Twenty-two Randomized controlled trials (RCTs) were assessed with 667 patients and 1595 implants (short implant:767, Long implant:835). No significant difference of implant survival rate was recorded for short and long implant (at patient level: RR: 1.01, 95% CI = 0.52-2.0, P = 0.87, I2 = 0%, at implant level RR = 1.09, 95% CI = 0.6-2.0, P = 0.7, I2 = 0%). Similarly marginal bone resorption was reported no difference for short and long implant (MD = 0.16. 95% CI: -0.23 = -0.08, P = 0.00, I2 = 74.83%). Biological complications were marginally higher for long implant (RR = 0.48, 95% CI = 0.23-0.8, P = 0.13, I2 = 29.11%). and prosthetic complications were marginally higher for short implants (RR=1.56, 95% CI=0.85-3.15, P = 0.43, I2 = 0%).

Conclusion

There was no significance difference in implant survival rate and marginal bone resorption recorded for both the short implant and long implant with sinus graft, in the patients rehabilitated with posterior atrophic maxilla. Hence, short implant is a suitable alternative to long implant with sinus graft, for the rehabilitation posterior atrophic maxilla.

Histological and Histomorphometric Evaluation of New Bone Formation after Maxillary Sinus Augmentation with Two Different Osteoconductive Materials: A Randomized, Parallel, Double-Blind Clinical Trial

This study aimed to investigate the histological features of deproteinized equine bone mineral (DEBM) and anorganic bovine bone (ABB) after human sinus augmentation with the lateral approach. Twenty-three sinus augmentations were performed in 16 patients (male: 10/female: 6) using DEBM or ABB in a randomized fashion. Healing took place over the next 6 months. Bone core biopsies (N = 23) were obtained for each subject prior to placing the dental implants. The biopsies were processed for both histological descriptions and histomorphometric analysis. Statistical analyses were applied as appropriate, defining statistical significance as p < 0.05. Core bone biopsies revealed no differences in terms of newly formed bone between groups, or differences in terms of tissue inflammation. Both DEBM and ABB appear to be suitable biomaterials for bone augmentation in sinus lift surgery in the short term. However, dedicated studies are required to confirm these results and their stability in the long term.

The Influence of Residual Alveolar Bone Height on Graft Composition after Maxillary Sinus Augmentation Using Two Different Xenografts: A Histomorphometric Comparative Study

AIM

To evaluate the hypothesis of a correlation between the preoperative residual alveolar bone height (RBH) and graft maturation after maxillary sinus floor augmentation procedures using two different bone substitutes.

METHODS

A total of 20 patients who underwent unilateral maxillary sinus floor augmentation with either mineralized deproteinized bovine bone (DBBM) or a xenograft enriched with polymer and gelatin (NBS) were included in this prospective study. Six months after sinus surgery, bone biopsies were harvested with a 3.2 mm diameter trephine bur, prior to dental implant placement. Histomorphometric analysis was performed, and the results were correlated with the individual RBH. Implants were loaded after 5 months of insertion, and 1-year implant success and marginal bone level change were assessed.

RESULTS

RBH was 2.17 ± 1.11 mm (range 0.5-3.5 mm) and 2.14 ± 0.72 mm (range 0.5-3.0 mm) in the NBS and DBBM group, respectively. The biopsy analyses for the DBBM group showed woven bone increases by 5.08% per 1-mm increment of RBH; medullary spaces decreased by 9.02%, osteoid decreased by 4.4%, residual biomaterial decreased by 0.34%, and lamellar bone increased by 5.68% per 1-mm increase of RBH. In the NBS group, samples showed woven bone increases by 8.08% per 1-mm increase of RBH; medullary spaces decreased by 0.38%; osteoid increased by 1.34%, residual biomaterial decreased by 0.58%, and lamellar bone decreased by 5.50% per 1-mm increase of RBH. There was no statistically significant difference in the correlation between RBH and lamellar bone, woven bone, and osteoid, independently of the material used. Implant success was 100% in both groups, and marginal bone loss was 1.02 ± 0.42 mm in DBBM and 0.95 ± 0.31 mm in the NBS group after the 1-year follow-up.

CONCLUSION

In spite of the absence of significance, the observed trend for woven bone to increase and medullary spaces to decrease when RBH increases deserves attention. Residual bone dimension might be a determinant in the bone graft maturation after maxillary sinus augmentation.

Tenting effect of dental implant on maxillary sinus lift without grafting

Background/purpose

Maxillary sinus lift without grafting is an alternative procedure that is used to lower the risk of infection and facilitate the surgical procedure. The objective of this study was to evaluate the tenting effect of the dental implant by measuring the amount and morphology of bone formation around it.

Material and methods

49 implants were placed in 26 patients by maxillary sinus lift without grafting. Radiographic images were taken preoperatively and at 6 months postoperatively and used to evaluate the height of the residual bone, the width of the maxillary sinus, the amount of bone formation, and the adjacent tooth.

Results

The most common type of bone formed around the implant, as seen in 23 cases, was the same height as the apex of the implant; in 11 cases, it was 0–2 mm above the apex of the implant, and in 7 cases, 2 mm or more. Meanwhile, 5 cases showed defects. The tent type of bone formation, which showed more bone formation at the implant apex than in the surrounding bone, was overwhelmingly the most common. (80.4%) The amount of bone formation increased in proportion to the difference between the residual bone height and the implant length. (P < .001).

Conclusion

The amount of bone formation in the sinus lift without grafting increased in proportion to the length of the implants in the maxillary sinus due to the tenting effect of the implant in the maxillary sinus membrane.

Relationship between Cortical Bone Thickness and Cancellous Bone Density at Dental Implant Sites in the Jawbone

Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably affected by host bone quality and quantity, which is often assessed prior to surgery through dental cone-beam computed tomography (CBCT). Dental CBCT was used in this study to evaluate dental implant sites for (1) differences in and (2) correlations between cancellous bone density and cortical bone thickness among four regions of the jawbone. In total, 315 dental implant sites (39 in the anterior mandible, 42 in the anterior maxilla, 107 in the posterior mandible, and 127 in the posterior maxilla) were identified in dental CBCT images from 128 patients. All CBCT images were loaded into Mimics 15.0 to measure cancellous bone density (unit: grayscale value (GV) and cortical bone thickness (unit: mm)). Differences among the four regions of the jawbone were evaluated using one-way analysis of variance and Scheffe's posttest. Pearson coefficients for correlations between cancellous bone density and cortical bone thickness were also calculated for the four jawbone regions. The results revealed that the mean cancellous bone density was highest in the anterior mandible (722 ± 227 GV), followed by the anterior maxilla (542 ± 208 GV), posterior mandible (535 ± 206 GV), and posterior maxilla (388 ± 206 GV). Cortical bone thickness was highest in the posterior mandible (1.15 ± 0.42 mm), followed by the anterior mandible (1.01 ± 0.32 mm), anterior maxilla (0.89 ± 0.26 mm), and posterior maxilla (0.72 ± 0.19 mm). In the whole jawbone, a weak correlation (r = 0.133, p = 0.041) was detected between cancellous bone density and cortical bone thickness. Furthermore, except for the anterior maxilla (r = 0.306, p = 0.048), no correlation between the two bone parameters was observed (all p > 0.05). Cancellous bone density and cortical bone thickness varies by implant site in the four regions of the jawbone. The cortical and cancellous bone of a jawbone dental implant site should be evaluated individually before surgery.

Treatments for enhancing the biocompatibility of titanium implants

Titanium surface treatment is a crucial process for achieving sufficient osseointegration of an implant into the bone. If the implant does not heal sufficiently, serious complications may occur, e.g. infection, inflammation, aseptic loosening of the implant, or the stress-shielding effect, as a result of which the implant may need to be reoperated. After a titanium graft has been implanted, several interactions are crucial in order to create a strong bone-implant connection. It is essential that cells adhere to the surface of the implant. Surface roughness has a significant influence on cell adhesion, and also on improving and accelerating osseointegration. Other highly important factors are biocompatibility and resistance to bacterial contamination. Bio-inertness of titanium is ensured by the protective film of titanium oxides that forms spontaneously on its surface. This film prevents the penetration of metal compounds, and it is well-adhesive for calcium and phosphate ions, which are necessary for the formation of the mineralized bone structure. Since the presence of the film alone is not sufficient for the biocompatibility of titanium, a suitable surface finish is required to create a firm bone-implant connection. In this review, we explain and compare the most widely-used methods for modulating the surface roughness of titanium implants in order to enhance cell adhesion on the surface of the implant, e.g. plasma spraying, sandblasting, acid etching, laser treatment, sol-gel etc., The methods are divided into three overlapping groups, according to the type of modification.

Factors influencing marginal bone loss at a hydrophilic implant design placed with or without GBR procedures: A 5-year retrospective study

BACKGROUND

Ongoing marginal bone loss is a threat to the longevity of implant-supported prostheses.

AIM

The aim of the present study was to retrospectively evaluate the survival rate and factors affecting marginal bone levels at a hydrophilic implant design after 5 years in function.

MATERIALS AND METHODS

The study group consisted of 51 consecutive patients previously treated with 159 hydrophilic implants (Neoss Straight Proactive implants) and scheduled for annual check-ups with clinical and radiographic examinations during 5 years. Data were compiled for the entire study population as well as for two subgroups: one where guided bone regeneration (GBR) was performed (91 implants) and the other where no GBR procedures (68 implants) were performed. Marginal bone levels were measured from peri-apical radiographs taken at placement and annual follow-ups. Statistical analyses were applied to evaluate the effect of different factors on marginal bone remodeling.

RESULTS

Two implant failures, one from each subgroup, occurred during the first year of function resulting in an overall cumulative survival rate (CSR) of 98.7% after 5 years of loading. The mean marginal bone loss amounted to 0.7 ± 0.7 mm after 1 year and 0.8 ± 0.6 mm after 5 years. No implants showed more than 3 mm bone loss after 5 years. Age, gender, implant position, biotype, implant diameter, implant length, indication, surgical/loading protocol, and ISQ at prosthesis delivery were found to affect bone remodeling. No significant differences or correlations were seen for smoking, jaw, bone quantity, bone quality, GBR, sinus lift, and ISQ at implant placement.

CONCLUSIONS

The present implant design performed well with few failures and minimal marginal bone loss after 5 years of loading. Marginal bone remodeling at implants is a complex phenomenon, which is affected by many patient-, procedure-, and implant-related factors that need to be further investigated.

Bone Regeneration Using a Three-Dimensional Hexahedron Channeled BCP Block Combined with Bone Morphogenic Protein-2 in Rat Calvarial Defects

It is important to obtain sufficient bone mass before implant placement on alveolar bone, and synthetic bone such as biphasic calcium phosphate (BCP) has been studied to secure this. This study used a BCP block bone with a specific structure of the three-dimensional (3D) hexahedron channel and coating with recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated carboxymethyl cellulose (CMC) was used to examine the enhancement of bone regeneration of this biomaterial in rat calvarial defect. After the preparation of critical-size calvarial defects in fifteen rats, defects were divided into three groups and were implanted with the assigned specimen (n = 5): Boneplant (untreated 3D hexahedron channeled BCP block), Boneplant/CMC (3D hexahedron channeled BCP block coated with CMC), and Boneplant/CMC/BMP (3D hexahedron channeled BCP block coated with CMC containing rhBMP-2). After 4 weeks, the volumetric, histologic, and histometric analyses were conducted to measure the newly formed bone. Histologically, defects in the Boneplant/CMC/BMP group were almost completely filled with new bone compared to the Boneplant and Boneplant/CMC groups. The new bone volume (P < 0.05) and area (P < 0.001) in the Boneplant/CMC/BMP group (20.12% ± 2.17, 33.79% ± 3.66) were much greater than those in the Boneplant (10.77% ± 4.8, 16.48% ± 9.11) and Boneplant/CMC (10.72% ± 3.29, 16.57% ± 8.94) groups, respectively. In conclusion, the 3D hexahedron channeled BCP block adapted rhBMP-2 with carrier CMC showed high possibility as an effective bone graft material.

Influence of residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone

OBJECTIVE

To evaluate the influence of the posterior residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

MATERIAL AND METHODS

Bilateral sinus bone augmentation was performed using anorganic bovine bone in 20 patients with residual bone height <2 mm in at least one site on each side. Trephine samples were removed at the implant insertion site 8 months after the grafting procedure, and histological and histomorphometric analyses were performed to examine the relative amount (%) of new bone, anorganic bovine bone, and soft tissue in the grafted area. Based on cone beam computed tomography evaluation, the sites of implant insertion were classified according to sinus width into narrow, average, and wide, and according to residual bone height into ≤2 and >2 mm.

RESULTS

A total of 146 implants were installed and 103 biopsies were evaluated. New bone formation in sites classified as narrow (69 sites), average (19 sites), and wide (15 sites) was 28.5% ± 9.24, 28.9% ± 8.61, and 30.3% ± 7.80, respectively. The mean posterior maxillary residual bone height was 4.0 ± 2.43 mm, and 26 and 77 sites were classified as ≤2 and >2 mm, respectively. New bone formation was 26.2% ± 9.10 and 29.8% ± 8.67 for residual bone height ≤2 and >2 mm, respectively. The differences were non-significant.

CONCLUSIONS

Within the limitations of the present study, posterior residual bone height and sinus width were not factors with influence on new bone formation in sinuses grafted exclusively with anorganic bovine bone after 8 months of healing.

Influence of exposing dental implants into the sinus cavity on survival and complications rate: a systematic review

BACKGROUND

After tooth loss, the posterior maxilla is usually characterized by limited bone height secondary to pneumatization of the maxillary sinus and/or collapse of the alveolar ridge that preclude in many instances the installation of dental implants. In order to compensate for the lack of bone height, several treatment options have been proposed. These treatment alternatives aimed at the installation of dental implants with or without the utilization of bone grafting materials avoiding the perforation of the Schneiderian membrane. Nevertheless, membrane perforations represent the most common complication among these procedures. Consequently, the present review aimed at the elucidation of the relevance of this phenomenon on implant survival and complications.

MATERIAL AND METHODS

Electronic and manual literature searches were performed by two independent reviewers in several databases, including MEDLINE, EMBASE, and Cochrane Oral Health Group Trials Register, for articles up to January 2018 reporting outcome of implant placement perforating the sinus floor without regenerative procedure (lateral sinus lift or transalveolar technique) and graft material. The intrusion of the implants can occur during drilling or implant placement, with and without punch out Schneiderian. Only studies with at least 6 months of follow-up were included in the qualitative assessment.

RESULTS

Eight studies provided information on the survival rate, with a global sample of 493 implants, being the weighted mean survival rate 95.6% (IC 95%), after 52.7 months of follow-up. The level of implant penetration (≤ 4 mm or > 4 mm) did not report statistically significant differences in survival rate (p = 0.403). Seven studies provided information on the rate of clinical complications, being the mean complication rate 3.4% (IC 95%). The most frequent clinical complication was epistaxis, without finding significant differences according to the level of penetration. Five studies provide information on the radiographic complication; the most common complication was thickening of the Schneiderian membrane. The weighted complication rate was 14.8% (IC 95%), and penetration level affects the rate of radiological complications, being these of 5.29% in implant penetrating ≤4 mm and 29.3% in implant penetrating > 4 mm, without reaching statistical significant difference (p = 0.301).

CONCLUSION

The overall survival rate of the implants into the sinus cavity was 95.6%, without statistical differences according to the level of penetration. The clinical and radiological complications were 3.4% and 14.8% respectively. The most frequent clinical complication was the epistaxis, and the radiological complication was thickening of the Schneiderian membrane, without reaching statistical significant difference according to the level of implant penetration inside the sinus.

Short implants in the posterior maxilla to avoid sinus augmentation procedure: 5-year results from a retrospective cohort study

BACKGROUND

Short implants present a promising approach for patients with advanced atrophy to avoid augmentative procedures. However, concerns about increased biological and technical complications due to an unfavorable implant-crown ratio are still present.

PURPOSE

The aim of the present retrospective study was to evaluate whether a reduced implant length has any impact on implant success and peri-implant hard and soft tissue health in implants placed in the posterior maxilla to avoid sinus augmentation procedures.

MATERIALS AND METHODS

Fourteen patients received a total of 30 implants of 7-mm length in the posterior maxilla. Implants with a mean loading period of 5 years (range 2-7 years) were followed up clinically and radiologically, with a focus on the peri-implant soft tissue parameters probing pocket depth (PPD), bleeding on probing (BoP), and the stability of the marginal peri-implant bone level.

RESULTS

None of the implants were lost, and no technical failures occurred. A mean PPD of 2.5 mm, a mean BoP of 13.3%, and a mean marginal bone loss (MBL) of 0.5 mm indicate healthy peri-implant hard and soft tissue conditions without signs of peri-implantitis.

DISCUSSION

The present results indicate the suitability of implants of 7-mm length to replace missing teeth in the posterior maxilla. An unfavorable implant-crown ratio or reduced bone-implant contact length seems to have no negative influence on midterm implant success or on peri-implant hard and soft tissue health.

Factors Influencing Resonance Frequency Analysis (RFA) Measurements and 5-Year Survival of Neoss Dental Implants

BACKGROUND

Diagnostic instruments based on resonance frequency analysis (RFA) can be utilised to assess dental implant stability during treatment and follow-up.

AIM

The aim of the present study was to investigate the influence of patient- and implant-related factors on implant stability and the 5-year implant survival. In addition, the influence of stability (ISQ value) at placement and abutment connection on implant survival was evaluated.

MATERIALS AND METHODS

RFA measurements from a total of 334 consecutive patients with 745 dental implants (Neoss Ltd., Harrogate, UK) were retrospectively analysed after at least 5 years in function. Statistics were used to evaluate the influence of the different variables on implant stability and implant survival. Odds ratio calculations were performed to compare the risk for implant failure using 60, 65, 70, and 75 ISQ as threshold levels at placement and loading.

RESULTS

A total of 20 implant failures in 14 patients were noted during the 5 years of follow-up, giving an overall cumulative survival rate (CSR) of 97.3% at the implant level and 95.8% at the patient level. Gender, jaw, position, bone quality, and implant diameter had an influence on implant stability at placement. Jaw, bone quality, and implant diameter had an influence on stability after 3-4 months of healing. More failures were observed in full than in partial rehabilitations. Age, gender, jaw, position, bone quantity, bone quality, implant diameter, and implant length had no influence on implant survival. Implants with ISQ values below the threshold levels showed lower survival rates compared to implants with values above these levels.

CONCLUSIONS

The present study showed a significantly higher risk for implant failure, showing an ISQ value below 70 and 75 at placement or after 3-4 months of healing. The results indicate that RFA measurements can be used to identify implants with increased risk for failure.

Dental Implants

Systematic reviews of literature over the period between 2008 and 2017 are discussed regarding clinical evidence for the factors affecting survival and failure of dental implants. The factors addressed include publication bias, tooth location, insertion torque, collar design, implant-abutment connection design, implant length, implant width, bone augmentation, platform switching, surface roughness, implant coatings, and the use of ceramic materials in the implant body and abutment.

Comparative Histological and Histomorphometric Results of Six Biomaterials Used in Two-Stage Maxillary Sinus Augmentation Model after 6-Month Healing

Objectives

To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period.

Materials and Methods

Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns.

Results

There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC.

Conclusions

Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688.

Maxillary sinus balloon lifting and deferred implantation of 50 osseointegrated implants: a prospective, observational, non-controlled study

The aim of this study was to assess the effectiveness of minimally invasive antral membrane balloon elevation (MIAMBE). Twenty-seven patients with severe resorption of the posterior maxilla were treated by balloon catheter-assisted sinus lift procedure with deferred implant placement. Panoramic radiographs and computed tomography scans were obtained prior to surgery and at 6 months after surgery, before implantation. Data collected following surgery included inflammation, pain, bleeding, infection, and haematoma. Pain and inflammation were recorded using a six-point verbal rating scale (VRS). The patients were followed up for an average of 15 months. The initial sinus floor height was measured for each planned implant and compared with the height at 6 months post-surgery. The average bone height gain was 8.10±3.45mm (range 0.5-13.95mm). Inflammation on the VRS ranged from 0 to 3 (mean 0.97±0.85), while pain ranged from 0 to 4 (mean 0.87±1.19). There was a perforation of the Schneiderian membrane smaller than 2mm in one case. In another case, the balloon lift procedure had to be aborted and changed to the conventional Tatum technique due to breakage of the balloon inside the sinus. The results of this study show the balloon sinus lift technique to be an easy procedure to perform, with apparently low rates of inflammation and pain, and to provide sufficient quantity and quality of bone for the placement of osseointegrated implants.

Bone grafting for alveolar ridge reconstruction. Review of 166 cases

Objective:

to investigate the predictive factors of failure in bone grafts for alveolar ridge augmentation and implant surgery.

Methods:

we reviewed the charts of 166 patients operated between 1995 and 2014. A total of 248 grafting procedures were performed. We submitted the data to the binomial test at 5% significance.

Results:

grafts to gain width of the alveolar ridge (65.32%) were more frequent than sinus lifting (p<0.0001) and the number of grafts to the posterior maxilla (48.8%) was greater than in other regions (p<0.01); 6.04% of the grafts were lost. The losses in anterior (p<0.0309) and posterior (p<0.0132) maxilla were higher than in the mandible. There were 269 ​​implants installed in the grafted areas, of which only 4.83% were lost. The number of implants lost (4.51%) in areas of onlay grafts was not statistically higher than those placed after sinus lifting (2.63%, p<0.2424). Losses were greater in the anterior (53.85%) and posterior (38.46%) maxilla than in the mandible (p<0.031). Regarding patients' age, 76.92% of the lost grafts (p<0.006) and 80% of the lost implants (p<0.001) were installed in patients over 40 years.

Conclusion:

failure rate was higher both for grafts and dental implants in the maxilla and in patients over 40 years of age.

Objetivo:

investigar os fatores preditivos de falhas em enxertos ósseos para aumento do rebordo alveolar e cirurgia de implantes.

Métodos:

os prontuários de 166 pacientes, operados entre 1995 e 2014, foram revistos. Um total de 248 enxertos foi realizado. Os dados foram submetidos ao teste binomial a 5% de significância.

Resultados:

os enxertos para ganho em espessura do rebordo alveolar (65,32%) foram mais frequentes do que levantamentos de seio maxilar (p<0,0001) e o número de enxertos para a região posterior da maxila (48,8%) foi maior do que em outras regiões (p<0,01). Foram perdidos 6,04% dos enxertos. As perdas em maxila anterior (p<0,0132) e posterior (p<0,0309) foram maiores do que na mandíbula. Foram instalados 269 implantes nas áreas enxertadas e apenas 4,83% perdidos. O número de implantes perdidos (4,51%) em áreas de enxertos em bloco não foi estatisticamente maior do que na área de seios maxilares enxertados (2,63%) (p<0,2424). As perdas foram maiores na região anterior (53,85%) e posterior (38,46%) da maxila em relação a mandíbula (p<0,031) e, 76,92% dos enxertos (p<0,006) e 80% dos implantes perdidos (p<0,001), foram instalados em pacientes com mais de 40 anos de idade.

Conclusão:

maior taxa de falhas foi observada para enxertos e implantes dentários realizados em maxila e em pacientes com mais de 40 anos de idade.

Sinus floor elevation procedures to enable implant placement and integration: techniques, biological aspects and clinical outcomes

Implant treatment in an atrophied edentulous posterior maxilla constitutes a challenge for the therapeutic team. The authors of the present study acknowledge that modern micro-rough surface implants in lengths of about 8-10 mm or longer and of different brands are similarly successful. Consequently, the authors propose that the use of different sinus floor elevation techniques should be considered when < 8 mm of bone is available below the maxillary sinus. The type of sinus floor elevation technique selected is mainly based on residual vertical bone height, marginal bone width, local intrasinus anatomy and the number of teeth to be replaced, although other factors (such as surgical training and surgical experience) may have an impact. It is proposed that a transcrestal sinus floor elevation approach can be considered as a first-choice method for single tooth gaps in situations with sufficient width for implant placement and a residual bone height of 5-8 mm, while lateral sinus floor elevation, with or without grafting materials, is indicated when < 5 mm of bone is available and when several teeth are to be replaced. With regard to time of implant placement, a one-stage procedure is preferred provided that high primary stability can be ensured.

Long-Term Implant Survival After 100 Maxillary Sinus Augmentations Using Plasma Rich in Growth Factors

PURPOSE

To identify determinants of long-term implant survival after sinus augmentation procedure (SAP) using a combination of plasma rich in growth factors (PRGF) and graft material.

MATERIALS AND METHODS

Patients were included in this retrospective study if they underwent SAP through a lateral wall approach using PRGF in combination with mainly xenograft, and received implants restored for at least 1 year. Sociodemographic, behavioral and implant characteristics (clinical factors, implant details, surgical details, prosthesis details, and complications) were analyzed.

RESULTS

Sixty-seven patients received 217 implants in 100 augmented sinuses. The mean follow-up was 7.2 years. Overall, 22 implants failed in 15 patients (90% cumulative implant survival). Multivariable models showed greater implant survival with implants placed with ≥5 mm of residual crestal bone height (RBH) compared with those placed with <3 mm of RBH. There was also an improvement in survival comparing implant lengths. In addition, immediate loading of implants significantly increased the risk of implant failure.

CONCLUSION

The use of PRGFs for maxillary sinus grafting may be an effective and safe treatment option for the rehabilitation of atrophic edentulous posterior maxillae. However, randomized clinical trials are needed to confirm these findings.

Do Clinical and Radiological Assessments Contribute to the Understanding of Biomaterials? Results From a Prospective Randomized Sinus Augmentation Split-Mouth Trial

The present prospective randomized split-mouth trial reports on the 3-year clinical and radiological follow-up investigation of implants placed 7 months after sinus augmentation with 2 different bone substitute materials. The aim of the study was to complete the histologic observation of cellular reactions by analyses of the implants and the volumetric changes of the augmented bone substitute materials. A sinus augmentation split-mouth trial was performed in 14 patients with the synthetic bone substitute material Nanobone (NB) and the xenogeneic Bio-Oss (BO). Changes in volume and density of the augmented biomaterials were investigated by analysis of computed tomography scans, taken immediately after augmentation and after 7 months. Clinical implant parameters were assessed after 3 years of loading. Both bone substitute materials underwent nonsignificant volume reduction and significant increase in bone density over an integration period of 7 months. No significant differences concerning volume and bone density were observed between the groups. Three years after loading, 51 of 53 implants were in situ with no peri-implant infections, and only a few soft-tissue variations were present. The present prospective randomized study showed that no differences could be observed clinically and radiologically. Accordingly, it seems that both biomaterials, independent of their physicochemical composition, enable clinical success and long-time stability for dental implants. Interestingly, the histological results showed distinct differences in cellular reactions: While the xenogeneic BO induced a mild tissue reaction with only few multinucleated giant cells and comparably low vascularization, the synthetic NB induced a multinucleated giant cell-triggered tissue reaction with an increase of vascularization. Thus, the present study showed that a combination analysis-histological, clinical, and radiological-is necessary for a detailed assessment of a biomaterial's quality for clinical application.

Autologous Periosteum-Derived Micrografts and PLGA/HA Enhance the Bone Formation in Sinus Lift Augmentation

Sinus lift augmentation is a procedure required for the placement of a dental implant, whose success can be limited by the quantity or quality of available bone. To this purpose, the first aim of the current study was to evaluate the ability of autologous periosteum-derived micrografts and Poly(lactic-co-glycolic acid) (PLGA) supplemented with hydroxyl apatite (HA) to induce bone augmentation in the sinus lift procedure. Secondly, we compared the micrograft's behavior with respect to biomaterial alone, including Bio-Oss® and PLGA/HA, commercially named Alos. Sinus lift procedure was performed on 24 patients who required dental implants and who, according to the study design and procedure performed, were divided into three groups: group A (Alos + periosteum-derived micrografts); group B (Alos alone); and group C (Bio-Oss® alone). Briefly, in group A, a small piece of periosteum was collected from each patient and mechanically disaggregated by Rigenera® protocol using the Rigeneracons medical device. This protocol allowed for the obtainment of autologous micrografts, which in turn were used to soak the Alos scaffold. At 6 months after the sinus lift procedure and before the installation of dental implants, histological and radiographic evaluations in all three groups were performed. In group A, where sinus lift augmentation was performed using periosteum-derived micrografts and Alos, the bone regeneration was much faster than in the control groups where it was performed with Alos or Bio-Oss® alone (groups B and C, respectively). In addition, the radiographic evaluation in the patients of group A showed a radio-opacity after 4 months, while after 6 months, the prosthetic rehabilitation was improved and was maintained after 2 years post-surgery. In summary, we report on the efficacy of periosteum-derived micrografts and Alos to augment sinus lift in patients requiring dental implants. This efficacy is supported by an increased percentage of vital mineralized tisssue in the group treated with both periosteum-derived micrografts and Alos, with respect to the control group of Alos or Bio-Oss® alone, as confirmed by histological analysis and radiographic evaluations at 6 months from treatment.

Radiological evaluation of maxillary sinus anatomy: A cross-sectional study of 300 patients

OBJECTIVE

The aim of the present study was to evaluate the principal anatomical characteristics of the maxillary sinus using Cone Beam Computed Tomography (CBCT) in order to facilitate prevention of intra- and post-operative complications.

MATERIALS AND METHODS

Three hundred CBCT scans from patients undergoing implant surgery were analysed. The following anatomical structures were evaluated: (1) Residual ridge height (RRH) and width (RRW); (2) Ridge bone density (BD); (3) Maxillary sinus angle (MSA); (4) Maxillary sinus lateral wall thickness (LWT); (5) Schneiderian membrane thickness (MT); (6) Maxillary sinus septa (SS); (7) Posterior superior alveolar artery (PSAA).'

RESULTS

Mean patient age was 59.5±13.6. Mean RRH at upper second premolar (2PM) was 8.66±3.95mm, 4.90±2.28mm at first molar (1M), and 5.26±2.13mm at second molar (2M). Mean RRW was 6.72±2.69mm at 2PM, 6.87±2.65mm at 1M and 7.09±2.80mm at 2M. Bone density was 330.93±211.02 Hounsfield Units (HU) at first molar position and MSA was 73.39±15.23°. LWT was 1.95±0.98mm. Mean Schneider Membrane thickness (MT) was 1.82±1.59mm; MT was ≤3mm in 72.9% of patients and >3mm in 27.10%. 20.56% of patients presented bucco-palatal oriented septa with a mean height of 13.11±3.82mm. PSAA was observed in 48.60% and mean distance to the top of the ridge was 13.15±3.71mm, and was mostly observed inside the sinus (53.85%).

CONCLUSIONS

CBCT scanning has been shown to be a useful tool for evaluating maxillary sinus anatomical variations. CBCT should be considered the gold standard when evaluating the maxillary sinus area.

Comparison between mineralized cancellous bone allograft and an alloplast material for sinus augmentation: A split mouth histomorphometric study

BACKGROUND

Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone, hydroxyapatite, β-tricalcium phosphate, anorganic deproteinized bovine bone, and combination of these and others. Yet, the issue of the optimal graft material for sinus floor augmentation is controversial.

PURPOSE

This prospective, randomized split-mouth study was undertaken to histomorphometrically compare a biphasic calcium phosphate (BCP) alloplastic bone substitute and a human bone mineral allograft (freeze-dried bone allograft, FDBA) in patients undergoing bilateral maxillary lateral sinus floor augmentation.

MATERIAL AND METHODS

Apico-coronal core biopsies were harvested at 9 months from 26 bilateral sites in 13 treated patients. Specimens were processed for histological and histomorphometrical analyses.

RESULTS

Newly formed bone (NB) was evident in all specimens with values of 27.5% and 24.0% at the FDBA and BCP sites, respectively (P = .331). The residual graft particle values were 12.5% and 25.4% (P = .001), and the connective tissue values were 60.0% and 50.6%, respectively. The osteoconductive value was 52.6% for the FDBA and 26.7% for the alloplast (P = .001). The values for the measured residual graft particles, connective tissue, and osteoconductivity, but not for NB, showed highly significant differences between the two groups. All sections in the alloplast material showed evidence of a light chronic inflammatory infiltrate, mainly comprising lymphocytes and multinucleated giant cells.

CONCLUSIONS

Both graft materials are suitable for sinus floor augmentation, with the allograft material being more osteoconductive.