Atrophic Posterior Maxilla Research Articles

Clinical evaluation of modified transalveolar sinus floor elevation and osteotome sinus floor elevation in posterior maxillae: study protocol for a randomized controlled trial

BackgroundImplant placement in the posterior maxilla is often complicated by the insufficient bone volume. While transalveolar sinus floor elevation (TSFE) has been proven as a predictable surgical procedure to increase the bone height in the posterior maxilla, questions in regard to the necessity of the bone grafting during the sinus lift and the question of whether TSFE could be performed when the residual bone height is below 5 mm are still debated. Furthermore, high-quality evidence comparing the clinical outcome of transalveolar sinus floor elevation with osteotome and modified sinus floor elevation with crestal non-cutting drills is limited.Methods/designOne hundred twenty adult patients who fit the inclusion criteria are being recruited from the Peking University Hospital of Stomatology First Clinical Division (Beijing, China). All patients are assigned to one of four groups according to a table of random numbers. Participants will receive (1) TSFE using osteotomes with bone grafting, (2) TSFE using osteotomes without bone grafting, (3) modified TSFE with bone grafting, or (4) modified TSFE without bone grafting. In a one-year follow-up period, implant survival rates, complications, implant stability, bone remodeling around the implant, and patient-reported outcome (visual analog scale for intraoperative discomfort and postoperative pain) will be observed and documented. The implant stability will be gauged by the resonance frequency analysis six times (at baseline and weeks 6, 8, 12, 16, and 26), and the bone remodeling will be observed and compared via radiographic examinations.DiscussionThe result of the trial will potentially contribute to better decision making in atrophic posterior maxilla when implant placement is needed. Therefore, if the outcome is deemed favorable, the use of the modified TSFE would achieve an outcome equivalent to that of the traditional TSFE while introducing less trauma and postoperative discomforts. Separately, whether the bone graft procedure is necessary for the TSFE will also be discussed.Trial registrationThe study has been registered in ClinicalTrials.gov under the identifier number NCT03445039. Registered on 26 February 2018.

Slit‐Window Technique: An Innovation That Simplifies Lateral Sinus Floor Elevation

IntroductionImplant placement in an atrophic posterior maxilla is challenging due to sinus pneumatization and presence of insufficient bone volume. Sinus floor elevation (SFE) is a feasible approach to increase the available alveolar bone dimensions. It is known that the maxillary sinus has a potential for healing and bone formation without the need of bone grafts or bone substitutes. However, current graft‐free sinus SFE approaches are technique sensitive and non‐reliable in consistent bone formation. This paper introduces the slit‐window technique as a novel and simple technique to perform graft‐free sinus floor elevation.Case PresentationA 66‐year‐old male presented with edentulous regions in the posterior maxilla and bilateral sinus pneumatization. The treatment included SFE using the graft‐free slit‐window technique on the right site and traditional lateral SFE with bone augmentation on the left site. Two implants were placed simultaneously during sinus lift procedures in each side. The slit‐window technique was performed using a rigid barrier membrane in conjunction with stabilizing bony slits to tent the Schneiderian membrane superiorly. Healing was uneventful for implants in both sides. Six months postoperatively, the amount of bone formation in the non‐grafted site was comparable to that of the grafted site.ConclusionSlit‐window sinus floor elevation procedure is a simple technique to elevate the floor of the sinus without the need for bone grafting.

Crestal endoscopic approach for evaluating sinus membrane elevation technique

Closed sinus lifting is a unique technique in being simple and less invasive (Summers, Compendium 15(6):698, 1994). However, it is blind to assess the safety of sinus lining during lifting without perforation. Previously, sinus membrane was assessed endoscopically in an invasive way. We aimed to judge clinically the sinus membrane integrity after crestal elevation by a direct simple less invasive endoscopic visual assessment through the crestal osteotomy site. To confirm undetected perforation, the sinus membrane was monitored dynamically by introducing the endoscope through a trephined opening in the lateral wall of the sinus (Nkenke et al., Int J Oral Maxillofac Implants 17(4):557–66, 2002).PatientsTwelve patients suffering atrophic posterior maxillae ranging 3–5 mm bone height below the sinus membrane were included to perform closed sinus lifting with simultaneous immediate implant placement under direct endoscopic assessment.ResultsThe floor was lifted without perforation in 83.33% of cases. However, it varied according to its thickness. Minor perforations occurred in two cases (16.67%). Both perforations were detected from the crestal endoscopic view while one of them was detected from the lateral endoscopic approach.ConclusionCrestal endoscopic access gives better direct vision to the membrane than the induced opening in the lateral wall of the maxillary sinus. Moreover, it uses the same prepared osteotomy site without doing any extra procedures. Perforation depends on the thickness of sinus lining and its ability to stretch during elevation. Intact crestal sinus floor elevation can never be guaranteed under endoscopic monitoring especially with thin irregular membranes.

Clinical Outcomes of Bicortical Engagement Implants in Atrophic Posterior Maxillae: A Retrospective Study with 1 to 5 Years Follow-up.

Bicortical dental implantation technique was regarded as an alternative to internal sinus lift technique with bone grafting in dental implantation in atrophic maxillae. The purpose of this retrospective study was to evaluate the survival rates and bone stability of 6- and 10-mm implants in the posterior maxilla using bicortical dental implantation techniques after 1 to 5 years of prosthetic loading. A total of 53 patients received posterior maxillary implant treatments. Of these, 31 patients received bicortical dental implantation (group A), and 25 patients received traditional implantation (group B). Three patients received an implant with bicortical engagement and another implant without bicortical engagement. The survival rates were calculated, and the marginal bone heights were measured on radiographs at baseline and follow-up. The survival rate of group A was 100%. In contrast, the survival rate of group B was only 74.68%, with survival rates of 51.85% in the 6-mm implant subgroup and 93.33% in the 10-mm implant subgroup. In terms of variations in implant marginal bone heights, a significant difference was found only between the 6-mm subgroups in groups A and B. Significant intrasinus bone gain was found on the mesial and distal sides of the implants in group A. Application of bicortical dental implantation techniques with 6-mm implants could achieve better clinical outcomes in atrophic posterior maxillae.

Clinical and Radiographic Performance of Rough Surfaced Implants Placed in the Atrophic Posterior Maxilla With Sinus Membrane Elevation Without Bone Grafting: A Prospective and Preliminary Study

The aim of the present prospective and preliminary study was to compare the clinical and radiographic outcomes of 2 types of rough surfaced implants after implant placement in the atrophic posterior maxilla with sinus membrane elevation without bone grafting using the crestal approach. All clinical and radiographic records for 28 patients who had received 40 implants were included in the present study. The patients returned for radiographic and clinical examinations at 1, 3, and 6months and every 6months thereafter after implantation. Cone-beam computed tomography images were taken to evaluate the amount of bone gain in the maxillary sinus. Standardized periapical digital radiographs were taken to evaluate the changes in the crestal peri-implant bone level and peri-implant fixture radiolucency. The Kaplan-Meier survival estimates demonstrated a 100% probability of survival to 24months. No significant differences were found in cervical bone loss (CBL) or residual bone height (RBH) between the TS III CA group and the TS III SA group during the 2-year follow-up period after implant placement. The CBL values according to gender, implant placement region, prosthesis type, and the time of implantation were not significantly different between the 2 groups. The results of the present preliminary study demonstrate that 2 types of rough surfaced implants placed in the atrophic posterior maxilla with sinus membrane elevation without a bone graft have good clinical and radiographic outcomes.

Lateral sinus grafting for implant therapy

Sinus grafting procedure is used to increase the osseous tissue for implant-supported prosthetic purposes. The sinus floor elevation (SFE) technique is the most commonly used technique for the implant rehabilitation of an atrophic posterior maxilla. SFE is a predictable procedure performed achieving high implant survival rate and its success depends on an accurate radiographic and clinical analysis.

Does the adjunctive use of platelet-rich plasma to bone graft during sinus augmentation reduce implant failure and complication? Systematic review and meta-analysis.

Prosthetic treatment of the posterior edentulous maxilla may require bone augmentation to enable the placement and integration of dental implants. This constitutes a complex healing situation, and resorption of the grafted bone and failure of the implants often occurs. The application of platelet-rich plasma (PRP) has been suggested to improve incorporation and preservation of bone grafts. The objective was to assess the effectiveness of PRP on the implant failure and complication rate, when used as an adjunctive material with bone graft in sinus floor augmentation. An electronic search of two databases (PubMed and Cochrane) was performed to identify randomized controlled trials (RCTs) in patients requiring sinus augmentation and implant placement in the posterior edentulous maxilla with or without using PRP as an adjunctive material to the bone graft. Data were extracted independently by two reviewers. The Cochrane tool was used for assessing the quality of included studies. Meta-analysis was performed for the included RCTs. Nine RCTs were identified, four of which were included in the study. Three of these trials were judged to be at unclear risk of bias and one was at low risk of bias. The meta-analysis revealed no difference between the PRP versus non-PRP groups regarding implant failure and complication rate. The meta-analysis revealed no statistically significant difference regarding implant failure and complication rate of implants placed in the atrophic posterior maxilla with sinus floor augmentation with or without PRP as an adjunctive material to the bone graft. This finding should be interpreted with great caution given the serious numerical limitations of the included studies.

Sinus floor elevation with platelet-rich fibrin alone: A Clinical retrospective study of 1-7 years.

BackgroundSeveral sinus floor elevation procedures for implant placement have been introduced. The present study aimed to evaluate the implants placed with Platelet-rich fibrin (PRF) alone in atrophic posterior maxillae and survival rates and the potential factors associated with implant loss.Material and MethodsThis retrospective study evaluated 71 implants in 34 patients after 1-7 years’ follow-up time. Statistical models were used to determine the implant survival and the potential factors associated with loss.ResultsOverall, 7 implants were lost, and the cumulative survival rate at 7 years by implant-based and patient-bases analyses were 85.5% and 85.7%, respectively. The mean residual bone height (RBH) was 4.26 mm. The implant survival rate was significantly lower at RBH < 4 mm than RBH ≥ 4 mm.ConclusionsThis retrospective study showed that sinus floor elevation with PRF alone could be applied in cases of lower RBH. However, it should be carefully performed in cases of RBH < 4 mm before surgery. Key words:Platelet-rich fibrin, dental implant, sinus augmentation, retrospective study.

Multiple Perforations of the Sinus Floor During Maxillary Sinus Floor Augmentation to Provide Access to the Bone Marrow Space: A Technical Report.

Sinus floor augmentation is a routinely used surgical technique for increasing the bone height/volume of the atrophic posterior maxilla. Optimal integration of the implanted augmentation material within the newly formed bone will-at least partly-depend on adequate vascularization to ensure sufficient recruitment of osteoblast and osteoclast precursor cells. The present technical note describes a modification intended to facilitate increased blood inflow into the augmented space. After preparation of the lateral window and elevation of the Schneiderian membrane, the cortical bone of the sinus floor is perforated several times either by using a piezoelectric device or a microsurgical handpiece with the corresponding tip or bur; these perforations should extend into the trabecular bone. The experiences with this modified technique after 12 patients are presented and discussed. It is expected that by means of this relatively simple technique, increased blood and cell inflow into the augmented space is achieved. This may, in turn, enhance new bone formation and improve the integration of the augmentation material.

Stress Analysis of Zygomatic Implants on the Augmented Maxillary Sinus: Is It Necessary to Graft?

Zygomatic implants are becoming an ideal therapy with advanced implant-supported prosthetic treatment for the posterior atrophic maxilla. The purpose of this study is to examine the quantity and distribution of stress, which was caused by zygomatic implants placed using intrasinus method with or without augmentation to the atrophic posterior maxilla. In this study, 3-dimensional atrophic edentulous maxilla models with and without sinus augmentation are designed with computer-aided programs. Stress analysis was carried out on the created computer models for maxillary alveolar cortical bone, for cortical bone in the zygomaticomaxillary suture, and for zygomatic spongy bone at the apex of the zygomatic implant and for metal substructure of Von Misses stress data. Having augmented the maxillary sinus with graft, it was observed that after the loading especially in the posterior region, the tensile and compressive stresses on the alveolar crest was distributed more homogeneously and the stress generated on the cortical bone was reduced through the graft. Although zygomatic implants are graftless solutions for athrophic maxilla, sinus augmentation will be useful for bearing stress around the implants.

The Sinus Membrane-Maxillary Lateral Wall Complex: Histologic Description and Clinical Implications for Maxillary Sinus Floor Elevation.

Maxillary sinus floor elevation has been documented as a safe and predictable procedure for gaining vertical bone height in the atrophic posterior maxillae. Conversely, there is a lack of basic research on the characteristics of the union between the sinus membrane (SM) and the bone. Clinical implications of an impaired union in healthy or pathologic membranes remain unknown. The objective of this study was to present a comprehensive histologic and morphologic description of the sinus membrane-lateral bone wall complex. In 14 fresh cadaver heads, 28 lateral wall sinus augmentation procedures were performed to obtain SM samples. Samples were assessed using hematoxylin-eosin, Masson trichrome, and toluidine blue staining and immunofluorescence and immunohistochemistry procedures. Specimens were coded and studied by a trained examiner using an optical microscope at ×4, ×10, ×40, and ×100 objectives. Thickness and inflammation status were assessed in these samples. Overall SM thickness of the samples was 0.40 ± 0.12 mm and was positively correlated to the inflammatory condition of the membranes. Such low values are the consequence of limited inflammation. Most of the fibers and cells in the deeper layers of the SM ran in a horizontal direction, oriented parallel to the underlying bone wall. In the immunohistochemistry study, 3 out of 7 samples showed a certain degree of nestin expression, suggesting osteogenic potential in spite of the elderly specimens. Large variations in thickness across the SM were found. These were noted to be partially correlated to the SM inflammatory status. The vast majority of the fibers were oriented parallel to the maxillary lateral wall, and only a few isolated areas showed a stronger perpendicular attachment. This might indicate the surpassing importance of the SM inflammatory status, operator skill, and other anatomical factors over the sinus membrane-maxillary lateral wall complex interface. Moreover, about half of the SM investigated were positive for nestin, indicating their osteogenic potential.

Perspective of immediately loaded wide‐short implants in atrophic posterior maxilla

Perspective of immediately loaded wide‐short implants in atrophic posterior maxilla

Comparison of sinus lifting using lateral window technique in atrophic posterior maxilla with 1‐stage versus 2‐staged procedures: A retrospective study

Comparison of sinus lifting using lateral window technique in atrophic posterior maxilla with 1‐stage versus 2‐staged procedures: A retrospective study

Does atrophic posterior maxilla present a challenge for Bicon short implants?

Does atrophic posterior maxilla present a challenge for Bicon short implants?

Maxillary Sinus Floor Augmentation: a Review of Selected Treatment Modalities.

ABSTRACTObjectivesThe 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 MethodsA 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.ResultsHigh 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.ConclusionsThe 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.

Morphologic Patterns of the Atrophic Posterior Maxilla and Clinical Implications for Bone Regenerative Therapy.

Regenerative therapies are commonly needed prior to implant placement in the posterior maxilla following tooth extraction. The aim of this study was to investigate the anatomical features of the atrophic posterior maxilla that might affect surgical approach selection and technique and risk of intra- and postoperative complications. Cone beam computed tomography files were screened to identify pristine atrophic maxillary ridges in need of bone augmentation (ridge height < 10 mm). Ridge height and width and lateral wall thickness (LWT) were measured at different levels, and palatonasal recess and lateral wall morphology were calculated. The influence of site was assessed using generalized estimation equations. The linear correlation between parameters was estimated with Pearson coefficient, and principal component analysis (PCA) was performed to establish patterns of multiple correlations. In the 433 edentulous sites and 6,062 measurements analyzed, the strongest correlations corresponded to LWT measurements at the different levels. Most of the parameters examined presented linearity (P < .001), allowing establishment of four main morphologic patterns according to anatomical features. The anatomical structures of the atrophic posterior maxilla follow linear patterns that might predict complications due to an anatomical feature and thus success in regenerative therapy.

A prospective randomized controlled trial of two‐window versus solo‐window technique by lateral sinus floor elevation in atrophic posterior maxilla: Results from a 1‐year observational phase

Implant failures are more common when multiple missing posterior teeth need lateral sinus floor elevation owing to inadequate tissue maturation after grafting. Effects of lateral window dimensions on vital bone formation have rarely been compared. To compare endo-sinus bone formation between two- and solo-window techniques to rehabilitate multiple missing posterior teeth that need substantial augmentation. Patients with severely atrophic posterior maxilla were randomized to receive lateral sinus floor elevation via solo or two bony windows. Bone core specimens harvested from lateral aspect of the augmentation sites were histomorphometrically analyzed. Proportions of mineralized bone (MB), bone substitute materials (BS), and nonmineralized tissue (NMT) were quantified. Twenty-one patients underwent 23 maxillary sinus augmentations. One patient in each group dropped out during the follow-up period. Lateral window dimensions were 81.65 ± 4.59 and 118.04 ± 19.53 mm2 in the test and control groups, respectively. Histomorphometric analysis revealed mean MB of 42.32% ± 13.07% and 26.00% ± 15.23%, BS of 40.34% ± 9.52% and 60.03% ± 10.13%, and NMT of 18.14% ± 14.24% and 14.75% ± 10.38% in test and control groups, respectively, with significant differences. The two-window technique could facilitate faster maturation and consolidation of the grafted volume and is an effective alternative for rehabilitation of severely atrophic posterior maxilla with multiple missing posterior teeth.

Combination of straight and tilted implants for supporting screw-retained dental prostheses in atrophic posterior maxillae: A 2-year prospective study

ObjectivesTo evaluate the two-year survival rate (SR) and marginal bone loss (MBL) of fixed dental prostheses (FDPs) supported by straight (S) and tilted (T) implants under the influence of diverse study variables. MethodsA prospective investigation comprising 21 patients provided with a total of 27 maxillary screw-retained restorations fixed to 70 dental implants was developed. Two groups of implants were considered depending on their inclination with respect to the occlusal plane: Group 1 (S, n=37): straight/axial implants and Group 2 (T, n=33): tilted/angled fixations. Each FDP was supported by a combination of S and T implants. SR and MBL were assessed at the time of loading and two years after surgery. Patient-, surgical- and/or rehabilitation-related information was gathered. Data were statistically analysed at the α=0.05 significance level. ResultsAfter 24 months, a 100% SR was achieved and the MBL of S and T implants were statistically similar. T implants located in the molar region showed lower MBL than did those replacing premolars (p=0.031). ConclusionsUpright and angled fixations inserted at posterior maxillary areas resulted in comparable survival rates and peri-implant MBL after two years. The marginal bone resorption around tilted implants depended on their location. Clinical significanceScrew-retained restorations fixed to straight and tilted implants seem to be a safe treatment option in posterior atrophic maxillae.

EVALUATION OF STEREOLITHOGRAPHIC SURGICAL GUIDE IN INDIRECT SINUS LIFTING FOR IMPLANT PLACEMENT

INTRODUCTION: Due to the inherent characteristics of the posterior maxillary bone, oral rehabilitation with implants may present some difficulties related to poor quality and insufficient volume of bone due to sinus pneumatization. Maxillary sinus augmentation procedure is currently considered a highly predictable and safe technique that allows the insertion of implants into the atrophic posterior maxilla. The use of CAD-CAM stereolithographic surgical guide during sinus-lift procedure has been advocated for many years. OBJECTIVES: This study was designed to evaluate the accuracy of stereolithographic surgical stent in transcrestal sinus lifting for implant placement. MATERIALS AND METHODS: A total of fifteen implants were placed in 6 patients. They were selected to perform transcrestal sinus lifting with simultaneous implant placement using stereolithographic surgical stent. RESULTS: Merging the preoperative plan and immediate postoperative CBCT images showed statistically significant values of the accuracy. The mean difference of angulation of the inserted implants compared to the angulation projected by the stereolithographic stent was 7.03° ± 4.53°. The mean of total coronal differences was 1.56 mm ± 1.15 mm, while the mean of total apical differences was 1.75 ± 1.14 mm. CONCLUSIONS: For beginners, stereolithographic surgical stent is an acceptable tool for transcrestal sinus lifting with simultaneous implant placement especially for single implants.

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

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. 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. 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. 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.