Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus

Maxillary sinus lift augmentation: A randomized clinical trial with histological data comparing deproteinized bovine bone grafting vs graftless procedure with a 5-12-year follow-up

INTRODUCTION

Different protocols and procedures for sinus lift and implant placement are available, generally involving the use of grafts to increase the tissue volume and/or prevent the Schneiderian membrane from collapsing. Among xenografts, deproteinised bovine bone graft (DBBP) is frequently used in sinus lift procedures. Leaving an ungrafted space following membrane elevation has proven to have a bony regenerative potential as well. This study aimed to compare the clinical and histological features of sinus lift surgery performed with or without biomaterials.

METHODS

Patients with severe maxillary posterior atrophy (residual bone height 2-6 mm and residual crest thickness ≥4 mm), and in need of sinus lift surgery to allow the placement of three implants were enrolled and randomly divided into two groups. They underwent sinus lifts with DBBP (control) or with a graftless technique (test) and immediate placement of two implants (a mesial and distal one). After 6 months, a bone sample was retrieved from the area between the previously inserted fixtures, and a third, central implant was placed. The collected bone samples were analyzed morphologically and histomorphometrically. The patients were provided with prosthetic restorations after 6 months and followed up for 5-12 years.

RESULTS

Ten patients were enrolled in the test and nine in the control group. The 6-month follow-up showed in the control group an average augmentation of 10.31 mm (±2.12), while in the test group it was 8.5 mm (±1.41) and a success rate of 96.3% in the control and 86.7% in the test group (p > 0.05). The histological analysis evidenced the presence of new bone tissue surrounded by immature osteoid matrix in the test group, and a variable number of DBBP particles surrounded by an immature woven bone matrix in the control group.

CONCLUSION

The results of the present trial indicate that, with residual bone height of 2-6 mm and residual crest thickness ≥4 mm, sinus lift surgery with or without biomaterials followed by implant restoration, produces similar clinical and histological outcomes.

Mucosal cyst aspiration in conjunction with maxillary sinus elevation: A clinical cohort study

INTRODUCTION

Patients with mucosal cysts in the maxillary sinus require special consideration in patients who require implant therapy for the restoration when undergoing implant therapy for the restoration of the posterior maxillary dentition. Treatment strategies for these clinical situations remain controversial in the literature. Thus, this study seeks to describe a safe and effective therapeutic strategy for sinus augmentation in patients with pre-existing maxillary antral cysts.

METHODS

A total of 15 patients and 18 sinuses were consecutively enrolled in this cohort study and underwent maxillary antral cyst treatment by needle aspiration and simultaneous maxillary sinus augmentation (MSA). During surgical procedures, threeimplants (Zimmer Biomet, Indiana, USA) were positioned in 11 sinuses and two implants (Zimmer Biomet, Indiana, USA) were positioned in 5 sinuses.

RESULTS

Overall implant success and survival rates were 100% and 97.8%, respectively at 1 year and 5-year follow-ups. Crestal bone resorption averaged 0.3 ± 0.2 mm 5-year post-loading, showing bone stability. Implant survival rate at 5-year follow-up expressed predictability of the technique comparable to historical data when MSA was performed alone. Crestal bone resorption averaged 0.3 ± 0.2 mm 5 years post-loading and shows bone stability utilizing mucosal cyst aspiration with concomitant MSA procedures. Quality of life evaluation at 1-week post-op showed similar results to published historical data. In 81% (13 sinuses), the CBCT examination at 5-year follow-up showed no cyst reformation, in 19% (3 sinuses) cyst reformation was visible, but smaller in size when compared to the pre-op CBCT evaluation, and all the patients were asymptomatic.

CONCLUSIONS

Maxillary sinus mucosal cyst aspiration with concomitant MSA, may be a viable option to treat maxillary sinus cyst.

Effectiveness of Autologous Platelet Concentrates in the Sinus Lift Surgery: Findings from Systematic Reviews and Meta-Analyses

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

[Graftless maxillary sinus lift with simultaneous implant placement: a case report]

A maxillary sinus lift was performed without bone grafting in a 23-year-old female patient who required the placement of a dental implant in the edentulous area of tooth 16. The clinical and tomographic evaluation made it possible to plan and perform the maxillary sinus lift using the transcrestal approach and without the need for bone grafting. The residual ridge of 6mm allowed the placement of a simultaneous dental implant. After 6 months of tomographic follow-up, before prosthetic loading, a vertical bone height of 8.83 mm was achieved, resulting in a vertical bone gain of 2.83 mm. Additionally, an adequate integration of the dental implant was observed without postoperative complications. Transcrestal sinus lift without the use of bone graft is shown to be a viable, safe and effective technique for the simultaneous placement of dental implants in patients with bone atrophy in the maxillary area. This technique offers advantages such as reduced surgical time, less morbidity, lower cost and a faster healing process compared to conventional methods.

Osseodensification versus lateral window technique for sinus floor elevation with simultaneous implant placement: A randomized clinical trial on patient-reported outcome measures

OBJECTIVES

To compare patient-reported outcome measures and additional surgical outcomes after sinus floor elevation (SFE) with osseodensification (OD) versus lateral window (LW), both with simultaneous implant placement.

MATERIALS AND METHODS

Twenty participants requiring single-implant rehabilitation with residual bone height (RBH) ≤4 mm were enrolled. Pain experience, quality of life (QoL) via the Oral Health Impact Profile-14 (OHIP-14), analgesics intake, and other symptoms were self-reported for a week on a daily basis. Surgery duration, complications, and implant stability quotient at baseline (ISQ T0 ) and after 6 months (ISQ T6 ) were registered. Participants were followed up for 1 year.

RESULTS

From Day 0 (day of surgery) to Day 3, pain experience was significantly lower (p < 0.05) in the OD group. OHIP-14 score was significantly lower (p < 0.05) in the OD group on all postoperative days, except on Day 5. Average analgesics intake was significantly lower (p < 0.001) in the OD group. Surgery mean duration was significantly higher (p < 0.001) in LW compared to OD (71.1 ± 10.4 vs. 32.9 ± 5.3 min). After osseointegration period, all implants were successfully restored with screw-retained crowns.

CONCLUSIONS

Within the limitations of this study, it can be concluded that OD and LW techniques were similarly effective in SFE with simultaneous implant placement when RBH ≤ 4 mm. However, OD significantly outperformed LW in pain experience, impact on self-perceived QoL, surgery duration, postoperative edema, and analgesics intake.

Biological performance of a novel bovine hydroxyapatite in a guided bone regeneration model: A preclinical study in a mandibular defect in dogs

OBJECTIVES

This preclinical model study aims to evaluate the performance and safety of a novel hydroxyapatite biomaterial (Wishbone Hydroxyapatite, WHA) on guided bone regeneration compared to a commercially available deproteinized bovine bone mineral (Bio-Oss, BO).

MATERIAL AND METHODS

Twenty-four beagle dogs were allocated to three timepoint cohorts (4, 12, and 26 weeks) of eight animals each. In all animals, four critical-sized, independent wall mandibular defects were created (32 defects/cohort). Each animal received all four treatments, allocated randomly to separated defects: WHA + collagen membrane (M), BO + M, no treatment (Sham, Sh), and Sh + M. At each timepoint, the specimens were harvested for histologic and histomorphometric analyses to determine the newly formed bone and osteoconductivity.

RESULTS

At 4 weeks, bone regeneration was significantly higher for WHA + M (46.8%) when compared to BO + M (21.4%), Sh (15.1%), and Sh + M (23.1%) (p < 0.05); at 12 and 26 weeks, regeneration was similar for WHA and BO. Bone-to-material contact increased over time similarly for WHA + M and BO + M. From a safety point of view, inflammation attributed to WHA + M or BO + M was minimal; necrosis or fatty infiltrate was absent.

CONCLUSIONS

WHA + M resulted in higher bone regeneration rate than BO + M at 4 weeks. Both BO + M and WHA + M were more efficient than both Sh groups at all timepoints. Safety and biocompatibility of WHA was favorable and comparable to that of BO.

Early tissue and healing responses after maxillary sinus augmentation using horizontal platelet rich fibrin bone blocks

BACKGROUND

The effects of horizontal platelet-rich fibrin (H-PRF) bone block on the healing and immune response during sinus augmentation have not been fully investigated histologically at early time points.

METHODS

Eighteenth male New Zealand white rabbits underwent bilateral sinus augmentation and were divided into two groups: deproteinized bovine bone mineral (DBBM) alone and H-PRF + DBBM (H-PRF bone block) group. Maxilla samples were collected at 3, 7 and 14 days post sinus augmentation procedures and analyzed using histological staining for the number of inflammatory cells, new blood vessels and evidence for early osteoclast bone turnover/remodeling. Furthermore, the effects of H-PRF bone blocks on the migration of osteoblasts and THP-1 macrophages were evaluated using a Transwell assay in vitro.

RESULTS

A higher number of immune cells were found in the H-PRF bone block group at 3 and 7 days post-surgery when compared to the DBBM alone group,most notably in the regions close to the mucosal lining and bone plates. Furthermore, a significantly greater number of new blood vessel formations and early signs of osteoclast development were found in the H-PRF bone block group at 14 days. The in vitro transwell assay further confirmed that culture medium from H-PRF bone block markedly promote the migration of osteoblasts and THP-1 macrophages.

CONCLUSIONS

The findings from this study have shown that H-PRF bone block is capable of increasing early immune cell infiltration leading to the acceleration of neovascularization and speeding the process of bone metabolism in vivo following maxillary sinus grafting with DBBM.

SinusC-Net for automatic classification of surgical plans for maxillary sinus augmentation using a 3D distance-guided network

The objective of this study was to automatically classify surgical plans for maxillary sinus floor augmentation in implant placement at the maxillary posterior edentulous region using a 3D distance-guided network on CBCT images. We applied a modified ABC classification method consisting of five surgical approaches for the deep learning model. The proposed deep learning model (SinusC-Net) consisted of two stages of detection and classification according to the modified classification method. In detection, five landmarks on CBCT images were automatically detected using a volumetric regression network; in classification, the CBCT images were automatically classified as to the five surgical approaches using a 3D distance-guided network. The mean MRE for landmark detection was 0.87 mm, and SDR for 2 mm or lower, 95.47%. The mean accuracy, sensitivity, specificity, and AUC for classification by the SinusC-Net were 0.97, 0.92, 0.98, and 0.95, respectively. The deep learning model using 3D distance-guidance demonstrated accurate detection of 3D anatomical landmarks, and automatic and accurate classification of surgical approaches for sinus floor augmentation in implant placement at the maxillary posterior edentulous region.

Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery-a 2-5-year retrospective study

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach (lSFE) and to determine the factors that influence the stability of the grafted area in the sinus cavity. Thirty patients (30 implants) treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the study. Five aspects of the implant (central, mesial, distal, buccal, and palatal bone heights [BHs]) were measured using cone-beam computed tomography (CBCT) before implant surgery, immediately after surgery (T0), 6 months after surgery (T1), and at the last follow-up visit (T2). Patients' characteristics were collected. A small bone window (height, (4.40 ± 0.74) mm; length, (6.26 ± 1.03) mm) was prepared. No implant failed during the follow-up period (3.67 ± 1.75) years. Three of the 30 implants exhibited perforations. Changes in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage surgery. Residual bone height (RBH) did not significantly influence BH changes, whereas smoking status and type of bone graft materials were the potentially influential factors. During the approximate three-year observation period, lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted area. In conclusion, lSFE using minimally invasive techniques was a viable treatment option. Patients who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral (DBBM) had significantly limited bone resorption in grafted area.

Clinical Evaluation of Short (6 mm) and Longer Implants Placed Side by Side in Posterior Partially Edentulous Area: A 3-Year Observational Study

Background

Short implants have been proposed as an alternative solution for the rehabilitation of atrophic posterior region.

Purpose

To compare the clinical outcomes between 6 mm short implants and conventional implants placed under similar conditions of bone quality and occlusal loading.

Materials and Methods

Nine patients received atone 6 mm implant and one standard-length (8 mm length or longer) implants in a total of 10 partially edentulous areas. Implants were left submerged for 3-6 months healing period and the screw-retained splinted prostheses were delivered. When the provisional or final restoration was placed, and at each year after loading, standardized intraoral radiograph was taken for themarginal bone level (MBL) changes around the implants. Subsequently, the patients were recalled for the clinical examination evaluating the implant survival, sulcus bleeding index, suppuration, and the incidence of prosthetic complications at every 6 months after the definitive crown delivery. The observation period was continued to 3 years (mean follow-up was 3.4 ± 0.3 years) after functional loading.

Results

Nine patients (10 short implants and 10 standard length implants) were selected in this study. Cumulative survival rates of the short implants and standard-length implants were 100% in both groups, and no biological and prosthetic complication were found in 3 years observation period. Cortical bone thickness of implant insertion sites was 1.39 ± 0.45 mm at short implants and 1.38 ± 0.69 mm at standard-length implants, and trabecular bone computed tomography values of implant insertion sites was 424.1 ± 290.1 at short implants and 410.9 ± 267.9 at standard-length implants. The MBL changes were -0.30 ± 0.71 mm at short implants and -0.19 ± 0.78 mm at standard-length implants at 3 years follow-up visit. No significant difference was found in the average of MBL changes between implant length.

Conclusions

Within the limits of this study, it can be concluded that 6 mm short implants in a posterior edentulous region showed excellent results compared with conventional implants.

CBCT for Diagnostics, Treatment Planning and Monitoring of Sinus Floor Elevation Procedures

Sinus floor elevation (SFE) is a standard surgical technique used to compensate for alveolar bone resorption in the posterior maxilla. Such a surgical procedure requires radiographic imaging pre- and postoperatively for diagnosis, treatment planning, and outcome assessment. Cone beam computed tomography (CBCT) has become a well-established imaging modality in the dentomaxillofacial region. The following narrative review is aimed to provide clinicians with an overview of the role of three-dimensional (3D) CBCT imaging for diagnostics, treatment planning, and postoperative monitoring of SFE procedures. CBCT imaging prior to SFE provides surgeons with a more detailed view of the surgical site, allows for the detection of potential pathologies three-dimensionally, and helps to virtually plan the procedure more precisely while reducing patient morbidity. In addition, it serves as a useful follow-up tool for assessing sinus and bone graft changes. Meanwhile, using CBCT imaging has to be standardized and justified based on the recognized diagnostic imaging guidelines, taking into account both the technical and clinical considerations. Future studies are recommended to incorporate artificial intelligence-based solutions for automating and standardizing the diagnostic and decision-making process in the context of SFE procedures to further improve the standards of patient care.

15-Year Retrospective Study on the Success Rate of Maxillary Sinus Augmentation and Implants: Influence of Bone Substitute Type, Presurgical Bone Height, and Membrane Perforation during Sinus Lift

Objectives

To evaluate the success rate of bone grafts and implants carried out at the Latin American Institute for Research and Dental Education (ILAPEO), considering the following: (i) the different pure bone substitutes (autogenous, xenogeneic, and alloplastic), (ii) the presurgical bone height, and (iii) how the treatment is compromised when membrane perforation occurs during sinus lift in maxillary sinus surgeries. Material and Methods. The initial sample comprised 1040 records of maxillary sinus lifting surgeries. After evaluation, the final sample retained 472 grafts performed using the lateral window technique with a total of 757 implants. The grafts were divided into 3 groups: (i) autogenous bone (n = 197), (ii) xenogenous bovine bone (n = 182), and (iii) alloplastic material (n = 93). One calibrated examiner classified the sample into two groups based on the residual bone height (<4 mm and ≥4 mm) of the area of interest measured on parasagittal sections of tomographic images. Data on membrane perforation occurrences in each group were collected; qualitative variables were described using frequency, expressed as percentages. The Chi-square test was used to analyze the success of the graft types and the survival rate of the implants as a function of the grafted material and the residual bone height. The Kaplan-Meier survival analysis was used to calculate the survival rate of bone grafts and implants according to the classifications adopted in this retrospective study.

Results

The success rate of grafts and implants was 98.3% and 97.2%, respectively. There was no statistically significant difference in the success rate among the different bone substitutes (p = 0.140). Only 8 grafts (1.7%) and 21 implants (2.8%) failed. There was a greater success rate for both grafts (96.5%) and implants (97.4%) when the bone height was ≥4 mm. The success rate in the 49 sinuses in which the membrane was perforated was 97.96% for the grafts and 96.2% for the implants. The follow-up periods after rehabilitation ranged from 3 months to 13 years.

Conclusions

Within the limitations of the data analyzed in this retrospective study, maxillary sinus lift was a viable surgical technique that enabled implant placement with a predictable long-term success rate, regardless of the type of material used. The presence of membrane perforation did not interfere with the success rate obtained for grafts and implants.

Simultaneous placement of short implants (≤ 8 mm) versus standard length implants (≥ 10 mm) after sinus floor elevation in atrophic posterior maxillae: a systematic review and meta-analysis

Purpose

The objective of this meta-analysis was to compare the clinical outcomes of using short implants (≤ 8 mm) inserted with osteotome sinus floor elevation (OSFE) and standard implants (≥ 10 mm) inserted with sinus floor elevation (SFE) in atrophic posterior maxillae with insufficient residual bone height (RBH).

Methods

An electronic search was performed on PubMed, EMBASE, and the Cochrane Library from 1994 to July 2022, in combination with a manual search of references in relevant articles. Randomized controlled trials (RCTs) that compared the clinical results between short and standard implant placement with SFE were included. The primary outcomes were implant survival rate and marginal bone loss (MBL); the secondary outcome was complication rate.

Results

Three RCTs were included, totaling 138 short and 156 standard implants. The results of the meta-analysis showed no significant differences between the short and standard implant groups in survival rate (RR = 1.02, 95% CI   0.96–1.08, p = 0.570), MBL (MD = − 0.13, 95% CI   − 0.32 to 0.07, p = 0.190) and complication rate (intra-surgical complication: RR = 1.14, 95% CI   0.46–2.83, p = 0.770; post-operative complication: RR = 1.34, 95% CI   0.71–2.55, p = 0.370).

Conclusions

Using short implants (≤ 8 mm) combined with OSFE might be an alternative to standard implants (≥ 10 mm) with SFE when the RBH of the posterior maxilla is insufficient. Based on a short-term clinical observation, short implants with OSFE show good results in terms of survival rate, MBL, and complication incidence.

Graphical Abstract

Single-crown restorations in premolar-molar regions: short (≤ 6.5) vs longer implants: retrospective cohort study

Purpose

To compare the survival, changes in marginal bone level and prosthetic complications rate of short (≤ 6.5 mm) and longer implants (≥ 7.5) supporting a single-crown restoration in the maxillary/mandibular premolar or molar region.

Methods

This cohort study was conducted following the STROBE statement recommendations for observational studies. Clinical outcomes of 88 short implants in 78 patients and 88 long implants in 88 patients were examined. All the implants had been placed by the same surgeon and restored following the same prosthetic concept; using a transepithelial abutment (intermediate abutment) and a screw retained restoration.

Results

All the implants were in function after the follow-up period since insertion (median: 31 months; range 11 to 84 for SiG vs median: 35 months; range: 6–117 for CG; p = 0.139). No statistical differences (p = 0.342) were observed related to prosthetic complications (screw loosening 2/88 vs 5/88 CG, ceramic chipping 1/88 vs 0/88, temporary crown resin chipping 1/88 vs 0/88 for SiG and CG, respectively) or related to marginal bone level (Mesial or Distal MBL ≥ 2 mm in 1/88 implants for SiG vs 3/88 for CG; p = 0.312).

Conclusions

Within the limitations of this study, no survival differences have been observed between short implants and longer implants in single-crown restorations in posterior maxilla/mandible.

Histomorphometric evaluation of different graft associations for maxillary sinus elevation in wide antral cavities: a randomized controlled clinical trial

OBJECTIVES

Pneumatization of the maxillary sinus can make it difficult, if not impossible, to install osseointegrated implants, and undertake their eventual functional rehabilitation, which may ultimately require regenerative techniques to achieve. This randomized controlled study proposed conducting a histological evaluation of the behavior of different graft materials in wide maxillary sinuses, at a height of 8 to 10 mm from the alveolar ridge, combined with bone remnants less than 3mm.

MATERIALS AND METHODS

Thirty-six patients underwent a sinus elevation procedure through the lateral window. The sinuses were randomly filled with the following materials (n=12/group): group 1, xenogenic bone + autogenous bone (ratio 70:30, respectively); group 2, xenogenic bone + L-PRF; and group 3, xenogenic bone. At 8 months, bone biopsies of engrafted sites were harvested and analyzed histomorphometrically in order to quantify newly formed bone tissue.

RESULTS

The results showed a greater area of newly formed bone for G1, averaging 2678.37 (1116.40) μm², compared with G2 at 984.87 (784.27) μm², and G3 at 480.66 (384.76) μm² (p < 0.05). Additionally, fewer xenogenic bone particles and a large amount of connective tissue were observed in G2.

CONCLUSIONS

In maxillary sinuses with large antral cavities, autogenous bone combined with xenogenic bone seems to demonstrate better graft remodeling and improve bone formation, compared with the addition of L-PRF.

CLINICAL RELEVANCE

L-PRF produces few advantages regarding new bone formation in the wide maxillary sinuses.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (REBEC) number RBR-2pbbrvg.

Long-Term Outcomes of Implants Placed in Maxillary Sinus Floor Augmentation with Porous Fluorohydroxyapatite (Algipore® FRIOS®) in Comparison with Anorganic Bovine Bone (Bio-Oss®) and Platelet Rich Plasma (PRP): A Retrospective Study

Purpose: The objective of this retrospective study was to evaluate the long-term clinical outcomes of bone regeneration procedures using algae-derived plant hydroxyapatite (Algipore^® FRIOS^®) compared with demineralized anorganic bovine bone (Bio-Oss^®), in combination with autologous blood-derived PRP. Materials and Methods: Partially edentulous patients with severe atrophy of posterior maxillary treated by means of the split bone technique in a two-stage grafting procedures were observed for up to seven years after implants placement. After surgeries, the natural porous fluorohydroxyapatite (FHA) (Algipore^® FRIOS^®; Group, n = 29) or anorganic bovine bone (Bio-Oss^® Group, n = 28) with autogenous bone in a 50:50 composite ratio with PRP, were administered in a 2.8-mm critical-size defect (CSD). Four months later, implants were placed at second-stage surgery. Results: A sample of fifty-seven consecutive patients who required sinus augmentation was included in the study, and 57 implants were placed. There was no drop out or loss of follow-up of any case. Clinical and radiographic examinations revealed a comparable pattern of newly formed bone in both groups after seven years of functional loading for implants placed after sinus augmentation using porous fluorohydroxyapatite and anorganic bovine bone. No significant difference in marginal bone loss was found around implants in both groups. Conclusions: The favorable implant outcomes suggest both biomaterials are suitable for sinus grafting in severely atrophic maxillae.

Bone quality effect on short implants in the edentulous mandible: a finite element study

Introduction

The aim of this study was to verify whether the use of short implants could optimize stress distribution of bone surrounding implants in atrophic mandibles with different bone qualities.

Methods

A three-dimensional model of the atrophic mandible with three levels of bone quality was made using computer software. Short implants (6 mm) and standard implants (10 mm) were used in four designs: Design 1 "All-On four", Design 2 "All-On-four" with two short implants, Design 3 four vertical implants with two short implants, and Design 4 six short implants. The distal short implants were placed at the first molar position. All twelve models were imported into finite element analysis software, and 110 N oblique force was loaded on the left second premolar. Maximum principal stress values of peri-implant bone and the volumes of bone with over 3000 microstrians (overload)were analyzed.

Result

Stress values and volumes of overload bone increased in all four groups with the decline of bone quality. The highest stress values were found in the cortical bone surrounding the Design 1 inclined implant in two lower bone quality mandibles, and the lowest in Design 3. However, Design 1 had less overload bone tissue than all three designs with short implants.

Conclusion

Short implants placed posteriorly helped decrease stress values in peri-implant bone, while bone surrounding short implants had a high resorption risk in low bone quality mandible.

Radiographic and Histomorphologic Evaluation of the Maxillary Bone after Crestal Mini Sinus Lift Using Absorbable Collagen—Retrospective Evaluation

Background: After tooth extraction, the alveolar bone loses volume in height and width over time, meaning that reconstructive procedures may be necessary to perform implant placement. In the maxilla, to increase the bone volume, a mini-invasive surgery, such as a sinus lift using the crestal approach, could be performed. Methods: A crestal approach was used in this study to perform the sinus lift, fracturing the bone and inserting collagen (Condress^®). The single dental implant was placed in the healed bone after six months. Results: The newly formed bone was histologically analyzed after healing. Histomorphological analyses confirmed the quality of the new bone formation even without graft biomaterials. This is probably due to the enlargement of the space, meaning more vascularization and stabilization of the coagulum. Conclusion: Using just collagen could be sufficient to induce proper new bone formation in particular clinical situations, with a minimally invasive surgery to perform a sinus lift.

The use of monophasic implants as an alternative of implant-prosthetic rehabilitation in the posterior maxilla with no sinus lift

BACKGROUND

Over the years, numerous studies and advanced technologies about dental implants have been evolved from the traditional two-stage procedure to immediate loading. Implants located in the posterior maxillary region allow to achieve an appropriate prosthetic support. The aim of this work was to solve the atrophied posterior maxilla, through monophasic implants with flapless technique and intraoral electro-welding.

METHODS

In this study were enrolled 120 patients between 20 and 68 years old (mean age of 34.2 years), where females predominate with 53.1% compared to 46.9% males. The patients were presented at the Oral Surgery Clinic of the Aldent University (Tirana, Albania), for a period 2009-2019. Briefly, 310 monophasic implants were placed, TRAMONTE type (Milan, Italy), to the posterior maxilla thus avoiding the sinus, with dense and wide threads, of different lengths and widths. The surgical technique was minimally invasive, flapless one. Data were expressed as mean + standard error (SEM) of all the radiographic outcomes obtained; and as statistical analysis was used the Student's t-test. P<0.5 and P<0.05, were considered significant.

RESULTS

A part of the patients were hypertensive and type 2 diabetic, then a negligible part were smokers, also a lack of oral hygiene was observed in 40% of cases. After 5 years of observation, it appeared that 95.9% of the implants were successful. Furthermore, the mesial and distal bone loss during the first three years was 0.1 mm, while after 5 years no continuation of bone loss was observed.

CONCLUSIONS

The application of monophasic implants must be performed according to approved protocols, considering the conditions of the posterior maxillary region, obtaining in this way a safe dental implantation.

Clinical performance of short versus standard dental implants in vertically augmented bone: an overview of systematic reviews

OBJECTIVE

To answer the question: What do we know so far about the clinical performance of short implants (≤ 7 mm) when compared to standard length implants in vertically augmented bone, as well as which is the overall confidence of the systematic reviews (SRs) about this topic?

MATERIALS AND METHODS

An overview of SRs was conducted. The searches were performed in six electronic databases and grey literature. SRs about short (≤ 7 mm) versus standard dental implants performance in vertically augmented bone were included. The assessed outcomes were marginal bone loss (MBL), implant survival (IS), prosthetic (PC) and biological complications (BC), costs, surgical time, and patient satisfaction. AMSTAR 2 was used to evaluate the overall confidence of included SRs.

RESULTS

Thirteen SRs were included. Nine of twelve SRs reported a lower MBL for the short implant group. All the included SRs showed no difference in the IS between groups. A higher rate of BC was reported for standard-length implants in four out of five SRs. No differences regarding PC were reported in four of five SRs. Information related to patient preference, cost, and surgery time were underreported. The confidence evaluation of the SRs was stratified as low for five SRs and critically low for eight SRs.

CONCLUSIONS

In an overall low-to-very low confidence levels, short implants appear to perform better in the mid-term (up to 5 years) than standard dental implants associated with vertical bone augmentation regarding MBL and BC, but they have a similar performance regarding IS rates and PC. There is an imperative need to improve the methodological quality of SRs, and efforts should focus on conducting RCTs to broaden the knowledge on this topic.

CLINICAL RELEVANCE

Short implants could represent a viable, simpler, and less invasive treatment when available bone height is limited.

Short Dental Implants (≤8.5 mm) versus Standard Dental Implants (≥10 mm): A One-Year Post-Loading Prospective Observational Study

Background: Recent data have shown that short dental implants can be the preferred treatment in most of cases of posterior atrophic alveolar ridges, offering higher survival and lower complication rates than long implants. The survival rates, stability, and marginal bone level changes were compared between short implants (7 and 8.5 mm) and standard-length implants (≥10 mm). Methods: Prospective observational study in which adult patients requiring ≥1 osseointegrated implants to replace missing teeth were recruited consecutively. A clinical examination was performed on the day the definitive prosthesis was placed and after 6 and 12 months. Implant stability quotient (ISQ), marginal bone level (MBL) changes, and the correlation between these parameters and the characteristics of the implants were evaluated. Results: A total of 99 implants were inserted (47 short, 52 standard) in 74 patients. The 12-month survival rate was 100%. ISQ values showed a similar pattern for both types of implants. No correlation was found between ISQ changes after one year and MBL values, nor between the latter and the characteristics of the implants. Conclusions: With clinical treatment criteria, shorter implants (7 and 8.5 mm in length) can be just as useful as standard-length implants in atrophic alveolar ridges, demonstrating similar rates of survival, stability, and crestal bone loss.

A Combined Lateral-Crestal Approach of Sinus Floor Elevation: Three Case Reports

This clinical report describes a combined lateral-crestal approach to elevate the sinus floor when placing implants on a wide maxillary posterior ridge. The buccally enlarged osteotomy broadens the vision of practitioners and facilitates access of instruments in the sinus. Compared with the traditional lateral approach of sinus lift, the proposed technique offers a more conservative treatment modality. A clinical study with sufficient subjects and long-term follow-up is needed to validate the potential and limitations of the proposed technique.

Different techniques in transalveolar maxillary sinus elevation: A literature review

Dental implant treatment in the posterior maxilla encounters bone quality and quantity problems. Sinus elevation is a predictable technique to overcome height deficiency in this area. Transalveolar sinus elevation is a technique that is less invasive and less time-consuming, first introduced for ridges with at least 5 mm of bone height. Many modifications and innovative equipment have been introduced for this technique. This review aimed to explain the modifications of this technique with their indications and benefits.

An exhaustive search in PubMed Central and Scopus electronic databases was performed until December 2020. Articles were selected that introduced new techniques for the transalveolar maxillary sinus approach that had clinical cases with full texts available in the English language. Finally, twenty-six articles were included. The data were categorized and discussed in five groups, including expansion-based techniques, drill-based techniques, hydraulic pressure techniques, piezoelectric surgery, and balloon techniques.

The operator’s choice for transalveolar approach techniques for sinus floor elevation can be based on the clinician’s skill, bone volume, and access to equipment. If possible, a technique with simultaneous implant placement should be preferred.

Long-Term Comparison of Survival and Marginal Bone of Implants with and without Sinus Augmentation in Maxillary Molars within the Same Patients: A 5.8- to 22-Year Retrospective Study

Maxillary sinus floor augmentation (MSFA) is widely used and considered a predictable procedure for implant placement. However, the influence of MSFA on implant survival and marginal bone loss (MBL) is still inconclusive. The purpose of this retrospective observational study is to evaluate the long-term genuine influence of MSFA on the survival and MBL of implants by comparing those with and without MSFA only in maxillary molars within the same patients. Thirty-eight patients (28 male and 10 female), with a total of 119 implants, received implants with and without MSFA, and were followed up for 5.8 to 22 years. Patient- and implant-related factors were assessed with a frailty model for implant survival and with generalized estimation equations (GEE) for MBL around the implant. No variables showed a statistical significance for implant failure in the frailty model. In GEE analysis for MBL, MSFA did not show any statistical significance. In conclusion, MSFA demonstrated no significant influence on implant failure and MBL in posterior maxilla in this study.

The effect of anatomy on osteogenesis after maxillary sinus floor augmentation: a radiographic and histological analysis

OBJECTIVES

To assess how anatomy and osteogenesis correlated with results of maxillary sinus floor augmentation (MSFA).

MATERIALS AND METHODS

Patients with partial edentulism and advanced atrophy of the posterior maxillae (≤ 4 mm residual bone height, RBH) underwent MSFA with sole deproteinized bovine bone matrix (DBBM) through a lateral approach. After a 6 to 9-month healing period, bone core biopsies were obtained from the sites of implant insertion for histological evaluation. The correlations between anatomical and histomorphometric variables were analyzed in a multiple regression model.

RESULTS

Forty-nine patients were recruited. One biopsy per patient was obtained from the augmented sinus. Thirty-seven bone core biopsies were intact and met the requirement for histomorphometry analysis. The mean (± standard deviation) percentages of vital bone (VB), remaining DBBM, and non-mineralized tissue were 18.25 ± 4.76%, 27.74 ± 6.68%, and 54.08 ± 6.07%, respectively. No statistically significant correlations were found between RBH and VB% (p = 0.44) or between sinus contour and VB% (p = 0.33). However, there was an inverse correlation between the sinus width (SW) and VB % (SW₁: R² = 0.13, p = 0.03; SW₂: R² = 0.15, p = 0.02).

CONCLUSIONS

After a healing period of 6-9 months, wider sinuses augmented with DBBM alone tended to have a lower proportion of new bone formation, while RBH and sinus contour did not appear to affect osteogenesis after MSFA.

CLINICAL RELEVANCE

This study emphasized the effect of anatomy on osteogenesis after MSFA. The result of the study may have an indication to the clinician that SW is a consideration when selecting the bone grafting material and deciding the healing period of MSFA.

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.

CT-based dentulous mandibular alveolar ridge measurements as predictors of crown-to-implant ratio for short and extra short dental implants

The purpose was to predict the crown-to-implant ratio variation in the edentulous posterior mandibles rehabilitated with short dental implants. Hence, vertical and horizontal dimensions of dentulous posterior mandibles in a sample of 18- to 25-year-olds were measured, and correlations of these dimensions with sex and site were investigated. Mandibular computed tomography scans from 100 subjects were considered. Vertical and horizontal bone and tooth measurements were taken at the sites of the second premolar (PM), and the mesial and distal roots of the first and second molars (M1m, M1d, M2m and M2d, respectively). A hypothetical crown-to-implant ratio (C/I R) was calculated assuming the insertion of short and extra short implants (5, 6 or 7 mm), at 1.5 mm from the inferior alveolar canal, maintaining the position of the existing occlusal plane. All vertical bone dimensions decreased from the PM to the M2d. Width measurements increased from the mesial (PM) to the distal sites (M1m, M1d, M2m and M2d). Males had significantly greater vertical and horizontal measurements than females at all sites. The mean C/I R was higher than 2 for all sizes of implant. The C/I R was lower for the second molar than for the second premolar, while it was similar for the first molar and the second premolar. Males had a higher C/I R than females. Computed tomography can be used to study the anatomical features of alveolar bone, and to predict some clinical aspects of prosthetic rehabilitation with implants, such as the crown-to-implant ratio in conditions of serious bone atrophy.

A novel digital approach for fixed full-mouth implant-supported rehabilitations: A case report

Successful rehabilitation of a patient’s entire dentition with implant-supported fixed prostheses requires restoration of function, esthetics and comfort. To achieve this goal, the clinician and laboratory technician must work in concert with one another to navigate the multiple steps from the patient’s initial evaluation to delivery of the final prostheses. Key to this is the ability of the clinician to provide the technician with detailed information regarding the patient’s extra- and intraoral characteristics in a manner that can be easily and accurately transferred to the lab bench where it then serves as the foundation for reconstruction of the dentition. In recent years, the impressive evolution of digital technology in dentistry has dramatically facilitated this complex process. The aim of this case report is to illustrate how digital profiles of a patient’s facial and intraoral features can be merged with one another and used to generate artificial teeth and gingival tissue of a full mouth implant supported rehabilitation via computer-aided design and computer-aided manufacturing (CAD/CAM) technology to successfully rehabilitate a patient that initially presented with a terminal dentition.

Key words:Facial scan, Zirconia, Implant-supported rehabilitation, Implant-supported prosthesis, Fixed prosthesis, Oral rehabilitation.

Implants with a Laser-microgrooved Collar Placed in Grafted Posterior Maxillary Extraction Sockets and in Crestally Grafted Sinuses: a 5-Year Multicentre Retrospective Study

Objectives

The aim of this retrospective multicentre cohort study was to compare clinical outcomes, soft tissues conditions and differences in marginal bone loss between implants with a laser-microgrooved collar placed in posterior maxillary extraction sockets grafted by 4 to 5 months, and in posterior maxillary pristine bone (spontaneously healed posterior maxillary extraction sockets) by means of osteotome-mediated sinus floor elevation, over a period of 5 years after functional loading.

Material and Methods

Patients of Group 1 underwent extractions with sockets preservation using porcine-derived bone, covered with collagen membrane. Group 2 underwent extractions without socket preservation. Patients of Group 1 received implants in grafted sites, and Group 2 received implants in spontaneously healed bone using a maxillary sinus lift with crestal approach.

Results

Over the observation period, the overall clinical success rate in Group 1 and Group 2 was 98% and 100%, respectively, with no differences between the procedures and implants used. Cumulative radiographic marginal bone loss ranged from 0.03 to 0.39 mm after 60 months of functional loading. There were no statistically significant differences in marginal bone loss between short and standard-length implants placed in grafted extraction sockets and in pristine bone.

Conclusions

Short and standard implants with a laser-microgrooved collar, placed in posterior maxillary extraction sockets grafted by 4 to 5 months, and in posterior maxillary pristine bone (spontaneously healed posterior maxillary extraction sockets) by means of osteotome-mediated sinus floor elevation, exhibited no statistical difference in success rate, clinical parameters and marginal bone loss.

[The alveolar antral artery prevalence and topography according to literature review]

INTRODUCTION

The lack of the available bone in the posterior maxilla is determined by the range of anatomical and topographical factors. Lateral sinus floor elevation is the procedure for vertical augmentation in this region. Several complications may occur while performing a lateral sinus lift and bleeding due to alveolar antral artery (AAA) damage is one of them.

The aim of the study is to analysis the different literature on AAA topographical features on cadaver species and on radiographic methods.

MATERIALS AND METHODS

A search of the English language literature was performed by three independent readers in the PubMed electronic database. Articles published between 2013 and 2018 on cadaver and radiographic studies were included.

RESULTS

The analysis included 9 articles. AAA prevalence in cadavers was 100% but AAA bone signs in CBCT studies varied between 32% and 93%. The diameter varied from 0.91 mm to 3.6 mm, and the distances from AAA to the sinus floor and to the alveolar ridge crest were 7.38-9.97 and 14.6-18.66 mm respectively.

CONCLUSION

Our literature analysis showed the difference between AAA prevalence in cadavers and in CBCT scans. The results show that even proper pre-operative planning of the lateral sinus lift with CBCT cannot guarantee avoiding AAA damage while performing the surgery.

Growth and Osteogenic Differentiation of Discarded Gingiva-Derived Mesenchymal Stem Cells on a Commercial Scaffold

BACKGROUND

In periodontal patients with jawbone resorption, the autologous bone graft is considered a "gold standard" procedure for the placing of dental prosthesis; however, this procedure is a costly intervention and poses the risk of clinical complications. Thanks to the use of adult mesenchymal stem cells, smart biomaterials, and active biomolecules, regenerative medicine and bone tissue engineering represent a valid alternative to the traditional procedures.

AIMS

In the past, mesenchymal stem cells isolated from periodontally compromised gingiva were considered a biological waste and discarded during surgical procedures. This study aims to test the osteoconductive activity of FISIOGRAFT Bone Granular® and Matriderm® collagen scaffolds on mesenchymal stem cells isolated from periodontally compromised gingiva as a low-cost and painless strategy of autologous bone tissue regeneration.

MATERIALS AND METHODS

We isolated human mesenchymal stem cells from 22 healthy and 26 periodontally compromised gingival biopsy tissues and confirmed the stem cell phenotype by doubling time assay, colony-forming unit assay, and expression of surface and nuclear mesenchymal stem cell markers, respectively by cytofluorimetry and real-time quantitative PCR. Healthy and periodontally compromised gingival mesenchymal stem cells were seeded on FISIOGRAFT Bone Granular® and Matriderm® scaffolds, and in vitro cell viability and bone differentiation were then evaluated.

RESULTS

Even though preliminary, the results demonstrate that FISIOGRAFT Bone Granular® is not suitable for in vitro growth and osteogenic differentiation of healthy and periodontally compromised mesenchymal stem cells, which, instead, are able to grow, homogeneously distribute, and bone differentiate in the Matriderm® collagen scaffold.

CONCLUSION

Matriderm® represents a biocompatible scaffold able to support the in vitro cell growth and osteodifferentiation ability of gingival mesenchymal stem cells isolated from waste gingiva, and could be employed to develop low-cost and painless strategy of autologous bone tissue regeneration.

Comparison of two anorganic bovine bone in maxillary sinus lift: a split-mouth study with clinical, radiographical, and histomorphometrical analysis

Background

Anorganic bovine bone (Bio-Oss®) has been extensively used for reconstruction of posterior area of maxilla in sinus lift procedure; however, a new graft material (Lumina-Bone Porous®), that has a different manufacturing process, has not been yet compared in clinical and histological terms. The manufacturing process of bovine bone graft is related to size and porosity of the particles, and this can change osteoconductive property of the material and bone formation. The use of Lumina-Porus® could improve bone formation, reduce the remaining particles of the biomaterial using a low-cost material. The aim of this research was to compare the clinical, radiological, and histomorphometrical results from maxillary sinus lift with two different anorganic bovine bone substitutes Bio-Oss® (control) and Lumina-Bone Porous® (test).

Results

A split-mouth study was performed with 13 volunteers. The mean bone ridge height in the deepest portion of maxillary sinuses floor was 3.11 ± 0.83 mm in the Bio-Oss® and 2.38 ± 0.75 mm in the Lumina-Bone Porous®. After sinus lift, the Bio-Oss® group shows bone ridge height of 11.56 ± 2.03 mm and Lumina-Bone® of 10.62 ± 1.93 mm. The increase in alveolar bone height scores was significant between pre-augmentation and 6 months after SL in both groups (p < 0.001). No statistical significant difference in newly formed bone in the Bio-Oss® group (20.4 ± 5.4%), and Lumina-Bone Porous® (22.8 ± 8.5%) was histomorphological observed (p > 0.05). On the other hand, the residual graft particles showed significant difference between the Bio-Oss® group (19.9 ± 8.6%) and Lumina-Bone Porous® (14.6 ± 5.6%) (p < 0.05). The survival rate of dental implants for augmented area with Lumina Bone Porous® was 88.88%, while for Bio-Oss® group was 100%.

Conclusion

Both materials Bio-Oss® and Lumina-Bone Porous® can be used in the maxillary sinus floor augmentation with good predictability in clinical, radiographical, and histological point of view.

Platelet-Rich Plasma in Maxillary Sinus Augmentation: Systematic Review

Background: Sinus augmentation can be performed with or without grafting biomaterials, and to date, there is no quality evidence regarding the augmentation of the sinus floor using only platelet concentrates, which can improve the healing period and enhance bone regeneration by stimulating angiogenesis and bone formation. The main objective of this paper was to assess the effect of the sole use of platelet concentrates in sinus augmentation in terms of newly formed bone, augmented bone height, and clinical outcomes and to assess the additional beneficial effects of platelet-rich fibrin (PRF) in combination with other grafting biomaterials. Methods: A systematic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Pooled analyses were performed with the Review Manager software. Results: For sinus elevation only using platelet concentrates, 11 studies met the inclusion criteria and were included for qualitative synthesis. Only one study was a clinical trial, which reported improved outcomes for the allograft group compared to the titanium-PRF (T-PRF) group. A total of 12 studies where PRF was used in addition to grafting biomaterials met eligibility criteria and were included in the review. Results from meta-analyses provided no additional beneficial effects of PRF in sinus augmentation in terms of bone height and percentage of soft tissue area. There was a statistically significant lower percentage of residual bone substitute material in the PRF (+) group compared to the PRF (−) group. The percentage of newly formed bone was slightly higher in the PRF (+) group, but this was not statistically significant. Conclusion: There is no robust evidence to make firm conclusions regarding the beneficial effects of the sole use of platelet concentrates in sinus augmentation. However, studies have shown favorable outcomes regarding implant survival, bone gain, and bone height. The use of PRF with other grafting biomaterials appears to provide no additional beneficial effects in sinus lift procedures, but they may improve the healing period and bone formation. Well-conducted randomized clinical trials (RCTs) are necessary to confirm the available results to provide recommendations for the clinical practice.

Short implants (≤6 mm) versus longer implants with sinus floor elevation in atrophic posterior maxilla: a systematic review and meta-analysis

OBJECTIVES

To compare the use of short implants (≤6 mm) in atrophic posterior maxilla versus longer implants (≥10 mm) with sinus floor elevation.

DESIGN

A systematic review and meta-analysis based on randomised controlled trials (RCTs).

DATA SOURCES

Electronic searches were conducted in PubMed, Embase and the Cochrane CENTRAL. Retrospective and prospective hand searches were also performed.

ELIGIBILITY CRITERIA

RCTs comparing short implants (≤6 mm) and longer implants (≥10 mm) with sinus floor elevation were included. Outcome measures included implant survival (primary outcome), marginal bone loss (MBL), complications and patient satisfaction.

DATA EXTRACTION AND SYNTHESIS

Risks of bias in and across studies were evaluated. Meta-analysis, subgroup analysis and sensitivity analysis were undertaken. Quality of evidence was assessed according to Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

A total of seven RCTs involving 310 participants were included. No significant difference in survival rate was found for 1-3 years follow-up (RR 1.01, 95% CI 0.97 to 1.04, p=0.74, I²=0%, moderate-quality evidence) or for 3 years or longer follow-up (RR 1.00, 95% CI 0.97 to 1.04, p=0.79, I²=0%, moderate-quality evidence). However, short implants (≤6 mm) showed significantly less MBL in 1-3 years follow-up (MD=-0.13 mm, 95% CI -0.21 to 0.05; p=0.001, I²=87%, low-quality evidence) and in 3 years or longer follow-up (MD=-0.25 mm, 95% CI -0.40 to 0.10; p=0.001, I²=0%, moderate-quality evidence). In addition, short implant (≤6 mm) resulted in fewer postsurgery reaction (RR 0.11, 95% CI 0.14 to 0.31, p<0.001, I²=40%, moderate-quality evidence) and sinus perforation or infection (RR 0.11, 95% CI 0.02 to 0.63, p=0.01, I²=0%, moderate-quality evidence).

CONCLUSIONS

For atrophic posterior maxilla, short implants (≤6 mm) are a promising alternative to sinus floor elevation, with comparable survival rate, less MBL and postsurgery reactions. Additional high-quality studies are needed to evaluate the long-term effectiveness of short implants (≤6 mm).

TRIAL REGISTERATION NUMBER

The protocol has been registered at PROSPERO (CRD42018103531).

The use of platelet-rich plasma in oral surgery: a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to evaluate the benefit of platelet rich plasma (PRP) in oral surgery.

MATERIALS AND METHODS

We performed a systematic search of the literature. The GRADE system was used to assess the certainty of the body of evidence.

RESULTS

We found 21 randomised controlled trials that met our inclusion criteria: 12 studies included patients with periodontal defects, five studies focused on healing of extraction sockets, three studies on sinus lift augmentation, and one study on periapical osseous defects. However, for the quantitative synthesis (meta-analysis), we evaluated "periodontal defects" studies only, since for other clinical contexts the number of studies were too low and the procedural heterogeneity was too high to allow pooling of data. PRP-containing regimens were compared to non-PRP-containing regimens. Primary outcomes for the evaluation of periodontal defects were probing depths, clinical attachment level, gingival recession, and radiographic bone defect. It is not usually clear whether or not the use of PRP compared to controls affects "probing depth" at long-term follow up; the between group differences were small and unlikely to be of clinical importance (i.e., very low quality of evidence). For the other outcomes analysed ("clinical attachment levels", "gingival recession", "bony defect"), we observed a very slight marginal clinical benefit of PRP compared to controls. The available evidence for these comparisons was rated as low quality as most of the studies selected showed inconsistency, imprecision, and risk of bias.

DISCUSSION

Evidence from a comparison between the use in oral surgery of PRP-containing regimens compared to other regimens not-containing PRP was of low quality. The results of the meta-analysis, limited to studies in patients with periodontal defects, document that PRP was slightly more effective compared to controls not-containing PRP.

Improved guided bone regeneration by combined application of unmodified, fresh autologous adipose derived regenerative cells and plasma rich in growth factors: A first-in-human case report and literature review

BACKGROUND

Novel strategies are needed for improving guided bone regeneration (GBR) in oral surgery prior to implant placement, particularly in maxillary sinus augmentation (GBR-MSA) and in lateral alveolar ridge augmentation (LRA). This study tested the hypothesis that the combination of freshly isolated, unmodified autologous adipose-derived regenerative cells (UA-ADRCs), fraction 2 of plasma rich in growth factors (PRGF-2) and an osteoinductive scaffold (OIS) (UA-ADRC/PRGF-2/OIS) is superior to the combination of PRGF-2 and the same OIS alone (PRGF-2/OIS) in GBR-MSA/LRA.

CASE SUMMARY

A 79-year-old patient was treated with a bilateral external sinus lift procedure as well as a bilateral lateral alveolar ridge augmentation. GBR-MSA/LRA was performed with UA-ADRC/PRGF-2/OIS on the right side, and with PRGF-2/OIS on the left side. Biopsies were collected at 6 wk and 34 wk after GBR-MSA/LRA. At the latter time point implants were placed. Radiographs (32 mo follow-up time) demonstrated excellent bone healing. No radiological or histological signs of inflammation were observed. Detailed histologic, histomorphometric, and immunohistochemical analysis of the biopsies evidenced that UA-ADRC/PRGF-2/OIS resulted in better and faster bone regeneration than PRGF-2/OIS.

CONCLUSION

GBR-MSA with UA-ADRCs, PRGF-2, and an OIS shows effectiveness without adverse effects.

Splinted and Nonsplinted Crowns with Different Implant Lengths in the Posterior Maxilla by Three-Dimensional Finite Element Analysis

The aim of this study was to evaluate stress distribution in the implants/components and bone tissue for splinted and nonsplinted prostheses with different lengths of implants using three-dimensional finite element analysis. Six models from the posterior maxillary area were used in simulations. Each model simulated three Morse taper implants of 4.0 mm diameter with different lengths, which supported metal-ceramic crowns. An axial load of 400 N and an oblique load of 200 N were used as loading conditions. Splinted prostheses exhibited better stress distribution for the implants/components, whereas nonsplinted prostheses exhibited higher stress in the first molar under axial/oblique loading. Implant length did not influence stress distribution in the implants/components. In cortical bone tissue, splinted prostheses decreased the tensile stress in the first molar, whereas nonsplinted prostheses were subjected to higher tensile stress in the first molar; implant length had no influence on stress distribution. Within the limitations of this study, we conclude that splinted prostheses contributed to better stress distribution in the implant/abutment and cortical bone tissue; however, the reduction in the implant length did not influence the stress distribution.

Controversies in Implant Surgery

Dental implants are a mainstream treatment protocol to replace missing teeth. Patient and clinician demands have led to shorter length and narrower diameter implants, immediately placed implants into infected sites, and the use of implants in children. This article reviews some of the controversial topics in implant dentistry, and presents the evidence that supports and challenges these newer techniques. Because long-term studies are often not available, especially for implants in infected sites, mini implants, and implants in the growing patient, the field continues to evolve.

Short Dental Implants (≤7mm) Versus Longer Implants in Augmented Bone Area: A Meta-Analysis of Randomized Controlled Trials

Aim:

The aim of this systematic review was to compare the survival rate and the marginal bone loss between short implants (≤7 mm) placed in the atrophic area and longer implants placed in the augmented bone area of posterior regions of maxillaries.

Methods:

Electronic search using three databases was performed up to May 2017 to identify Randomized Controlled Trials (RCT) assessing short implants survival with a minimal follow-up of 12 months post-loading. For the meta-analysis, a Risk Difference (RD) with the 95% Confidence Interval (CI) was used to pool the results of implant failure rate for each treatment group. For the marginal bone changes, Mean Differences (MD) with 95% CI were calculated.

Results:

Seven randomized controlled trials met the inclusion criteria, being included in qualitative and quantitative analyses. The RD between the short implant group and the control group was -0.02 (95% CI: -0.04 to 0.00), I²=0 and Chi²=3.14, indicating a favorable survival rate for short implant, but with no statistical significance (p=0.09).

Discussion:

For marginal bone loss, the mean difference was -0,13 (95%CI: -0.22 to -0.05), favoring the test group with statistical significance (p=0.002). The studies showed more heterogeneity for bone loss compared to survival rate. Short and longer implants showed similar survival rates after one year of loading, however the marginal bone loss around short implants was lower than in longer implants sites.

Conclusion:

Placement of implants ≤7 mm of length was found to be a predictable alternative for the rehabilitation of atrophic posterior regions, avoiding all the disadvantages intrinsic to bone augmentation procedures.

Membrane perforation rate in lateral maxillary sinus floor augmentation using conventional rotating instruments and piezoelectric device-a meta-analysis

Objectives

Maxillary sinus augmentation (MSA) is a successful and predictable intervention with low complication rates. Perforations of the Schneiderian membrane may occur impairing the general success. The aim of this study was to compare the incidence of membrane perforations between conventional rotating instruments and piezoelectric devices in a meta-analysis.

Material and methods

An electronic research on MEDLINE and PubMed database was performed evaluating the literature from 1980 till 2016. Meta-analysis was performed with the studies matching the inclusion criteria. The incidence of perforations between conventional and piezo during the lateral maxillary sinus floor elevation was determined, and forest plots and a t test for significance analysis were performed.

Results

The search provided 377 articles of which 69 could be included. Selected non-randomised and non-controlled prospective and retrospective studies were incorporated. Conventional rotary instruments were associated with a perforation rate of 24%, the piezoelectric devices with 8% with statistically significant difference between both modalities (p < 0.05).

Conclusion

Membrane perforations in MSA may be significantly reduced applying piezoelectrical devices for MSA.

Short implants had lower survival rates in posterior jaws compared to standard implants

Data sourcesPubMed/Medline, Embase and Cochrane Library databases supplemented by searches of the journals; Clinical Implant Dentistry and Related Research, Clinical Oral Implants Research, International Journal of Oral and Maxillofacial Implants, International Journal of Oral and Maxillofacial Surgery, Journal of Clinical Periodontology, Journal of Dentistry, Journal of Oral and Maxillofacial Surgery, Journal of Oral Implantology, Journal of Oral Rehabilitation, Journal of Periodontology, Periodontology 2000.Study selectionRandomised controlled trials (RCTs) and prospective studies with at least ten patients, published in the last ten years that compared short and standard implants and published in English were considered.Data extraction and synthesisA single author abstracted data with checking by a second reviewer. Methodological quality was assessed using the Jadad Scale and the Cochrane risk of bias tool. Risk ratios (RR) were calculated for implant survival rates, complications and prostheses failures and marginal bone loss was evaluated using mean difference (MD).ResultsThirteen studies consisting of ten RCTs and three prospective studies were included. The ten RCTs were considered to be of high quality. Two thousand six hundred and thirty-one implants were placed in 1269 patients (981 short and 1650 standard implants). Thirty-eight short implants failed (3.87%) and 45 standard implants (2.72%). Random effects meta-analysis found no statistically significant difference between standard implants and short implants placed in the posterior regions; RR =1.35 (95% CI; 0.82-2.22: P=0.24). Marginal bone loss was evaluated in nine studies and no differences in marginal bone loss were observed. Complications were reported by seven studies and no significant difference was seen between standard and short implants; RR= 0.54 (95% CI; 0.27-1.09: P = 0.08). There was also no significant difference in prosthesis failures between standard and short implants; RR= 0.96 (95% CI: 0.44-2.09: P = 0.92)ConclusionsShort implants showed marginal bone loss, prosthesis failures and complication rates similar to standard implants, being considered a predictable treatment for posterior jaws, especially in cases that require complementary surgical procedures. However, short implants with length less than 8 mm (4-7 mm) should be used with caution because they present greater risks for implant failures when compared to standard implants.

Comparing Short Dental Implants to Standard Dental Implants: Protocol for a Systematic Review

BACKGROUND

Short dental implants have been proposed as a simpler, cheaper, and faster alternative for the rehabilitation of atrophic edentulous areas to avoid the disadvantages of surgical techniques for increasing bone volume.

OBJECTIVE

This review will compare short implants (4 to 8 mm) to standard implants (larger than 8 mm) in edentulous jaws, evaluating on the basis of marginal bone loss (MBL), survival rate, complications, and prosthesis failure.

METHODS

We will electronically search for randomized controlled trials comparing short dental implants to standard dental implants in the following databases: PubMed, Web of Science, EMBASE, Scopus, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov with English language restrictions. We will manually search the reference lists of relevant reviews and the included articles in this review. The following journals will also be searched: European Journal of Oral Implantology, Clinical Oral Implants Research, and Clinical Implant Dentistry and Related Research. Two reviewers will independently perform the study selection, data extraction and quality assessment (using the Cochrane Collaboration tool) of included studies. All meta-analysis procedures including appropriate effect size combination, sub-group analysis, meta-regression, assessing publication or reporting bias will be performed using Stata (Statacorp, TEXAS) version 12.1.

RESULTS

Short implant effectiveness will be assessed using the mean difference of MBL in terms of weighted mean difference (WMD) and standardized mean difference (SMD) using Cohen's method. The combined effect size measures in addition to the related 95% confidence intervals will be estimated by a fixed effect model. The heterogeneity of the related effect size will be assessed using a Q Cochrane test and I2 measure. The MBL will be presented by a standardized mean difference with a 95% confidence interval. The survival rate of implants, prostheses failures, and complications will be reported using a risk ratio at 95% confidence interval (P<.05).

CONCLUSIONS

The present protocol illustrates an appropriate method to perform the systematic review and ensures transparency for the completed review. The results will be published in a peer-reviewed journal and social networks. In addition, an ethics approval is not considered necessary.

TRIAL REGISTRATION

PROSPERO registration number: CRD42016048363; https://www.crd.york.ac.uk/PROSPERO/ display_record.asp?ID=CRD42016048363 (Archived by WebCite at http://www.webcitation.org/6wZ7Fntry).

β-TCP/HA with or without enamel matrix proteins for maxillary sinus floor augmentation: a histomorphometric analysis of human biopsies

BACKGROUND

It is still unclear whether enamel matrix proteins (EMD) as adjunct to bone grafting enhance bone healing. This study compared histomorphometrically maxillary sinus floor augmentation (MSFA) with β-TCP/HA in combination with or without EMD in humans.

METHODS

In ten systemically healthy patients needing bilateral MSFA, one side was randomly treated using β-TCP/HA mixed with EMD (BC + EMD) and the other side using only β-TCP/HA (BC). After 6 months, biopsies were harvested from grafted areas during implant installation, being histologically and histomorphometrically analyzed. Differences between the groups considering new bone formation, soft tissues, and remaining BC were statistically evaluated.

RESULTS

All patients showed uneventful healing after MSFA, and dental implant installation was possible in all patients after 6 months. Histological analysis showed newly formed bone that was primarily woven in nature; it was organized in thin trabeculae, and it was occasionally in contact with residual bone substitute particles, which appeared in various forms and sizes and in advanced stage of degradation. Mean bone area was 43.4% (CI95 38.9; 47.8) for the BC group and 43.0% (CI95 36.6; 49.5) for the BC + EMD group. Mean soft tissue area was 21.3% (CI95 16.5; 26.2) for BC group and 21.5% (CI95 17.7; 25.3) for BC + EMD group, while the remaining biomaterial was 35.3% (CI95 36.6; 49.5) and 35.5% (CI95 29.6; 41.3) for BC and BC + EMD group, respectively.

CONCLUSIONS

MSFA with BC resulted in adequate amounts of new bone formation allowing successful implant installation; adding EMD did not have a significant effect.

Recent advances in dental implants

Dental implants are a common treatment for the loss of teeth. This paper summarizes current knowledge on implant surfaces, immediate loading versus conventional loading, short implants, sinus lifting, and custom implants using three-dimensional printing. Most of the implant surface modifications showed good osseointegration results. Regarding biomolecular coatings, which have been recently developed and studied, good results were observed in animal experiments. Immediate loading had similar clinical outcomes compared to conventional loading and can be used as a successful treatment because it has the advantage of reducing treatment times and providing early function and aesthetics. Short implants showed similar clinical outcomes compared to standard implants. A variety of sinus augmentation techniques, grafting materials, and alternative techniques, such as tilted implants, zygomatic implants, and short implants, can be used. With the development of new technologies in three-dimension and computer-aided design/computer-aided manufacturing (CAD/CAM) customized implants can be used as an alternative to conventional implant designs. However, there are limitations due to the lack of long-term studies or clinical studies. A long-term clinical trial and a more predictive study are needed.

Maxillary Sinus Floor Augmentation: a Review of Selected Treatment Modalities

Objectives

The objective of the present study is to present the current best evidence for enhancement of the vertical alveolar bone height and oral rehabilitation of the atrophic posterior maxilla with dental implants and propose some evidence-based treatment guidelines.

Material and Methods

A comprehensive review of the English literature including MEDLINE (PubMed), Embase and Cochrane Library search was conducted assessing the final implant treatment outcome after oral rehabilitation of the atrophic posterior maxilla with dental implants. No year of publication restriction was applied. The clinical, radiological and histomorphometric outcome as well as complications are presented after maxillary sinus floor augmentation applying the lateral window technique with a graft material, maxillary sinus membrane elevation without a graft material and osteotome-mediated sinus floor elevation with or without the use of a graft material.

Results

High implant survival rate and new bone formation was reported with the three treatment modalities. Perforation of the Schneiderian membrane was the most common complication, but the final implant treatment outcome was not influenced by a Schneiderian membrane perforation.

Conclusions

The different surgical techniques for enhancement of the vertical alveolar bone height in the posterior part of the maxilla revealed high implant survival with a low incidence of complications. However, the indication for the various surgical techniques is not strictly equivalent and the treatment choice should be based on a careful evaluation of the individual case. Moreover, further high evidence-based and well reported long-term studies are needed before one treatment modality might be considered superior to another.

Retrospective cohort clinical investigation of a dental implant with a narrow diameter and short length for the partial rehabilitation of extremely atrophic jaws

We investigated the short-term clinical outcomes of narrow-diameter short-length implants for the fixed-prosthetic partial rehabilitation of extremely resorbed jaws. Twenty-three patients requiring partial rehabilitations with narrow-platform short-length implants in any jaw were included in this study. In total, 30 implants 3.3 mm in diameter and 7 (n = 15 implants) or 8.5 (n = 15 implants) mm in length were inserted. The primary outcome measure was implant cumulative survival rate (CSR); the secondary outcome measures were marginal bone resorption at 1 and 3 years and the incidence of biologic and mechanical complications. Five patients (21.7%) with six implants (20%) were lost to follow-up. Two implants failed in two patients, yielding a CSR at 3 years of follow-up of 93.4%. The average (standard deviation) marginal bone resorption was 1.34 mm (0.95 mm) after the first year and 1.38 mm (0.78 mm) after the third year. Biologic complications occurred in three patients; mechanical complications occurred in three patients. Despite the limitations of the study, our findings show that the use of new narrow-diameter short-length implants for the rehabilitation of extremely atrophic regions is viable in the short-term, and can be considered a treatment alternative in extremely resorbed jaws.

Comparison of three different methods of internal sinus lifting for elevation heights of 7 mm: an ex vivo study

BACKGROUND

Various techniques are available for elevating the sinus membrane. The aim of this study is to evaluate three methods of indirect sinus floor elevation regarding elevation heights of 7 mm on the outcomes of membrane perforation, length of perforation, and time required to perform the procedure.

METHODS

Three different methods for indirect sinus lifting, bone added osteotome sinus floor elevation (BAOSFE), sinus floor elevation with an inflatable balloon, and crestal approach system (CAS kit) from OSSTEM, were assessed for their ability to lift the sinus without causing laceration of the Schneiderian membrane. The study was performed on 18 freshly slaughtered sheep heads (36 sinus lifts were done, 12 for each method). CBCT images of the heads were taken to assess the best location for the sinus lift. Then, the heads were bisected and the membrane was exposed from the medial aspect. After that, each method was performed. The intended elevation height was 7 mm. If the 7 mm were not reached, the maximum height of elevation was measured.

RESULTS

The method used was significantly associated with the occurrence of perforation (p value = 0.014) where BAOSFE was associated with the largest number of perforations (58.4%, n = 7) compared to 8.3% and 8.3% for the balloon and CAS kit methods, respectively. The odds ratio for perforation occurrence from BAOSFE compared to the CAS kit was significant (OR = 0.091, p = .022). No significant odds ratio was found for the balloon method compared to CAS kit. Additionally, the method used was significantly associated with time of operation and with the length of perforation (p value < 0.001) where CAS kit required the longest time and BAOSFE caused the biggest perforations.

CONCLUSIONS

The study shows that both the balloon and the CAS kit were superior to the BAOSFE in terms of safety in elevating the sinus membrane. Further, in vivo studies have to prove these findings.

Sinus floor elevation using implants coated with recombinant human bone morphogenetic protein-2: micro-computed tomographic and histomorphometric analyses

OBJECTIVES

The objective of this study was to determine the validity of a graft-free sinus floor elevation (SFE) procedure with simultaneous placement of recombinant morphogenetic protein-2 (rhBMP-2)-coated implants compared to uncoated control implants.

METHODS

In 10 rabbits, SFE was performed on both sides. Dental implants were randomly placed in the sinus filled with a blood clot. Test implants were coated with rhBMP-2, whereas in the control group, implants were uncoated. Micro-computed tomographic and histomophometric analyses were performed at 4 and 8 weeks, including measurement for newly formed bone height (NBHm).

RESULTS

Bone formation was evident along the implant surfaces up to the apex in test, but limited in control implants at 4 weeks. NBHm amounted to 5.1 mm (Q1 = 4.1; Q3 = 5.3) for test implants and to 3.4 mm (2.6; 3.7) for control implants at 4 weeks. NBHm then decreased to 8 weeks (3.4 mm (3.3; 3.7)) for test implants, whereas in control sites, NBHm increased slightly to 4.4 mm (4.1; 4.5) (p = 0.1250; p = 0.6250).

CONCLUSIONS

Implants coated with rhBMP-2 presented a strong osteogenic reaction at 4 weeks with more favorable outcomes in terms of bone formation along the implant surface up to the apex compared to uncoated control implants. Remodeling and resorption process between 4 and 8 weeks did not further improve the outcomes in the test, but in the control group.

CLINICAL RELEVANCE

The use of rhBMP-2-coated implants in a graft-free SFE might show an advantage in early implant stability to prevent collapse of membrane. However, a potential clinical benefit still needs to be proven.