A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

Enhancement of bone regeneration with the combination of platelet-rich fibrin and synthetic graft

INTRODUCTION

Platelet-rich fibrin (PRF) is a relatively new developed platelet concentrate with several benefits over platelet-rich plasma. The aim of this study was to compare healing properties of PRF and its combination with a ceramic synthetic material (graft) composed of hydroxyapatite and b-tricalcium phosphate in an animal model.

METHODS

A bone deficit was surgically created in each femoral condyle of 15 New Zealand white rabbits. In each animal, 1 limb had (a) PRF only and the other (b) PRF plus synthetic graft material randomly implanted. Experimental animals were killed 3 months postoperatively. Histological and radiological examinations were made by means of computed tomography and peripheral quantitative computed tomography.

RESULTS

Mean density of the healed bone was statistically significantly greater when synthetic material was used (P < 0.0005). Moreover, combination of PRF with the synthetic material resulted in more cortical and subcortical bone formation (P = 0.038 and P = 0.037, respectively).

CONCLUSIONS

The addition of the ceramic material significantly increased the formation of new bone, providing a better substrate for bone regeneration.

Sinus Floor Augmentation Using Straumann® BoneCeramic™ and Bio-Oss® in a Split Mouth Design and Later Placement of Implants: A 5-Year Report from a Longitudinal Study

BACKGROUND

Straumann® BoneCeramic™ is a synthetic biphasic calcium phosphate (BCP) aimed for sinus floor augmentation. Long-term follow-up of implants placed in BCP after sinus augmentation is still missing.

PURPOSE

The primary aim of the study was to compare survival rates and marginal bone loss of Straumann SLActive implants placed in either BCP (test) or Bio-Oss® (DBB) (control) after sinus floor augmentation. The secondary aim was to calculate graft sinus height at different time points.

MATERIALS AND METHODS

Bilateral sinus floor augmentation was performed in a split mouth model. Eleven patients (mean age 67 years) received 100% BCP on one side and 100% DBB on the contralateral side. After 8 months of graft healing, 62 Straumann SLActive implants were placed. After 5 years of functional loading (6 years after augmentation) of implants, marginal bone levels and grafted sinus height were measured, and implant survival and success rates were calculated.

RESULTS

After 5 years of loading, all prosthetic constructions were in function although two implants were lost in each grafting material. The overall implant survival rate was 93.5% (91.7% for BCP, 91.3% for DBB, and 100% for residual bone). The success rates were 83.3% and 91.3% for BCP and DBB, respectively. There was no statistically significant difference in mean marginal bone level after 5 years between BCP (1.4 ± 1.2 mm) and DBB (1.0 ± 0.7 mm). Graft height reduction (GHR) after 6 years was limited to 6.6% for BCP and 5.8% for DBB.

CONCLUSION

In this limited RCT study, the choice of biomaterial used for sinus floor augmentation did not seem to have any impact on survival rates and marginal bone level of the placed implants after 5 years of functional loading and GHR was minimal.

Longitudinal response of membrane thickness and ostium patency following sinus floor elevation: a prospective cohort study

OBJECTIVES

To investigate the influence of sinus floor elevation (SFE) on sinus physiology, including Schneiderian membrane thickness (MT) and ostium patency, using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Based on pre-established selection criteria, 53 patients in combination with 53 sinuses were referred for SFE with a lateral approach using deproteinized bone mineral. CBCT was performed prior to, immediately after surgery and before staged implant placement. The Schneiderian MT of the elevated region, ostium patency, and other clinical data was evaluated.

RESULTS

The two-stage sinus augmentation technique was applied in 33 males and 20 females. Four membrane perforations were observed during the surgical procedure. The Schneiderian membrane exhibited significant swelling immediately after augmentation (P < 0.0001), but this difference disappeared after a mean healing period of 7.51 months. The corresponding changes were also observed for ostium patency with a tendency of transient obstruction after surgery. Sinuses with flat mucosal thickening or pseudocysts did not present a liability of perforation compared to the normal cases, and the augmentation procedure was not likely to deteriorate the pathology of mucosal thickening or pseudocysts.

CONCLUSIONS

The results show that SFE with a lateral approach has no significant influence on MT and ostium patency after the healing period except for postoperative transient swelling and obstruction. Thickened membranes and antral pseudocysts in a small size might not be contraindications to SFE from the standpoint of the surgical impact on the Schneiderian membrane.

Sinus grafting and simultaneous removal of large antral pseudocysts of the maxillary sinus with a micro-invasive intraoral access

Large antral pseudocysts of the maxillary sinus (APCs) may hamper the elevation of the Schneiderian membrane during sinus grafting and may impair osteo-meatal complex patency after sinus augmentation. Therefore, these should be removed prior to or at the time of sinus grafting. This study presents a new technique that combines enucleation of large APCs during sinus grafting via a lateral approach with preservation of the Schneiderian membrane periosteal layer. Twelve patients underwent a sinus graft via lateral approach during the years 2004-2012. Simultaneous APC removal was achieved through a small additional bony access, preserving the integrity of the periosteal layer of the Schneiderian membrane. Nineteen implants were inserted at the time of sinus augmentation or during a second stage. Prosthetic rehabilitation was started at 4-6 months after implant placement. No patient developed surgical complications or APC recurrence. The survival rate of implants and related prostheses was 100% over a mean follow-up of 50 months (range 12-96 months) after completion of the prosthetic restorations. This technique may represent an effective procedure to achieve APC removal at the time of sinus grafting, preserving the integrity of the Schneiderian membrane periosteal layer.

Detection of the posterior superior alveolar artery in the lateral sinus wall using computed tomography/cone beam computed tomography: a prevalence meta-analysis study and systematic review

A systematic search of MEDLINE, Embase, and Proceedings Web of Science was undertaken to assess the prevalence of the posterior superior alveolar artery (PSAA) in the lateral sinus wall in sinus lift patients, as identified using computed tomography (CT)/cone beam computed tomography (CBCT). For inclusion, the article had to report PSAA detection in the bony wall using CT and/or CBCT in patients with subsinus edentulism. Studies on post-mortem findings, mixed samples (living and cadaveric), those presenting pooled results only, or studies performed for a sinus pathology were excluded. Heterogeneity was checked using an adapted version of the DerSimonian and Laird Q test, and quantified by calculating the proportion of the total variance due to between-study variance (Ri statistic). Eight hundred and eleven single papers were reviewed and filtered according to the inclusion/exclusion criteria. Ten studies were selected (1647 patients and 2740 maxillary sinuses (study unit)). The pooled prevalence of PSAA was 62.02 (95% confidence interval (CI) 46.33-77.71). CBCT studies detected PSAA more frequently (78.12, 95% CI 61.25-94.98) than CT studies (51.19, 95% CI 42.33-60.05). Conventional CT revealed thicker arteries than CBCT. It is concluded that PSAA detection is more frequent when CBCT explorations are used. Additional comparative studies controlling for potential confounding factors are needed to ascertain the actual diagnostic value of radiographic explorations for assessing the PSAA prior to sinus floor elevation procedures.

Palatal window osteotomy technique improves maxillary sinus augmentation in previously insufficient augmentation case

INTRODUCTION

Perforation of the Schneiderian membrane is the most common complication in sinus floor augmentation (SFA). When volume of grafting is qualified to prevent enlargement of the membrane perforation, lack of bone volume may occur in optimal site.

CASE PRESENTATION

SFA was performed in sites #24 to 26 in a 63-year-old male. However, a 10-mm size perforation of the Schneiderian membrane occurred in site #26. Although the sinus cavity was grafted with deproteinized bovine bone mineral (DBBM) after repair of membrane perforation, insufficient bone formation was observed on palatal and distal aspects of site #26 at 5 months after SFA. Although additional SFA was required for implant placement, it seemed to be difficult to elevate the membrane by a conventional lateral approach in the palatal aspect of the sinus floor (site #26). Considering the configuration of new bone formation, it was decided to perform the palatal antrostomy approach. The Schneiderian membrane was elevated without perforation, and the sinus cavity was grafted with DBBM mixed with venous blood. Two 12-mm long, 4.1-mm diameter implants were placed in sites #14 and 16. Four months after implant placement, abutment-connection surgery was successfully performed. The radiographic image indicated improved radiopacity, without obvious bone resorption in site #26.

CONCLUSION

The palatal window osteotomy technique could be considered as an alternative method for augmentation of maxillary sinus in cases where difficulty is encountered to elevate a membrane by a conventional approach (e.g., in cases in which buccal bone height is long).

The influence of sinus membrane thickness upon membrane perforation during lateral window sinus augmentation

OBJECTIVES

To investigate: (1) sinus membrane thickness in patients receiving lateral window sinus augmentation via cone-beam computed tomography (CBCT) and (2) the influence of Schneiderian membrane thickness upon membrane perforation during lateral window approach.

MATERIAL AND METHODS

A total of 73 subjects with 81 sinus lift procedures between years 2010 and 2013 were recruited consequently. Each patient selected had CBCT images in initial and immediately after surgery. The values and correlation between variables of membrane thickness, perforation rate, membrane morphology, residual bone height, and elevated bone height were evaluated.

RESULTS

The mean thickness of the Schneiderian membrane was 1.32 ± 0.87 mm. Perforation rate was lowest (7.14%) when membrane thickness was 1-1.5 mm. As membrane became thicker (≥2 mm) or thinner (<1 mm), the perforation rate increased abruptly. When examined the membrane thickness category, Class B (between ≥1 mm and <2 mm) had the lowest perforation rate. Statistically significant correlation was found between the perforation and the membrane thickness. The amount of the remaining bone height did not significantly correlate to the membrane thickness nor influence the membrane perforation.

CONCLUSIONS

This study demonstrated that membrane thickness was related to the sinus perforation during lateral window sinus augmentation. The perforation rate was lowest when the membrane thickness was 1-1.5 mm.

Graft Remodeling following Transcrestal Sinus Floor Elevation via the Gel-Pressure Technique (GPT) and Pasteous Nano-Crystalline Hydroxyapatite Bone Substitute

Bone grafting of the maxillary sinus is attempted to compensate for sinus pneumatization and permit reliable insertion of endosseous dental implants for prosthetic rehabilitation. The aim of the present clinical investigation was to study bone regeneration four months after transcrestal sinus floor elevation via the Gel-Pressure Technique (GPT) and application of pasteous nano-crystalline hydroxyapatite bone substitute. A total of 25 patients with deficient alveolar ridges in the posterior maxilla (mean residual bone height: 4.7 ± 1.8 mm) were subjected to 32 flapless transcrestal sinus floor augmentations and simultaneous insertion of 40 implants. Sinus membrane elevation height averaged 11.2 ± 2.7 mm and minimal vertical graft resorption of 0.1 mm was observed after four months. Radiographic bone density averaged 460 Hounsfield units in regions adjacent to the native jawbone (1 to 7 mm distance), while reduction of bone density by −7.2%, −11.3%, −14.8%, −19.6% and −22.7% was recorded in more apical regions of 8, 9, 10, 11, and ≥12 mm distance to the original sinus floor, respectively. The results suggest that graft remodeling is completed up to a distance of 7 mm within a healing period of four months after sinus augmentation using nano-crystalline hydroxyapatite bone substitute material.

Lateral Bone Window Closing Technique with Poly-L-Lactic Acid (PLLA) Membrane in the Augmentation of the Maxillary Sinus without Grafting Material: Evaluation of Bone Healing in a Rabbit Model

BACKGROUND

When augmenting the maxillary sinus without grafting material, the method used to cover the bony window is a subject of debate.

PURPOSE

The purpose of this study was to evaluate the poly-L-lactic acid (PLLA) membrane as closing material of the lateral window in a maxillary sinus augmentation without bone grafting.

MATERIALS AND METHODS

Augmentation of the maxillary sinus without grafting material and installation of titanium screws that fix the Schneiderian membrane were performed in 18 Japanese male white rabbits. The bony window was covered with a collagen membrane or PLLA membrane or no membrane. The animals were sacrificed at 4 or 8 weeks. New bone volume was calculated radiologically using microcomputed tomography (micro-CT). The samples were analyzed histologically after toluidine blue staining.

RESULTS

No significant differences were observed in the new bone volume, as measured by micro-CT. However, histomorphometric analysis demonstrated the superiority of the PLLA membrane in new bone formation compared with the collagen membrane.

CONCLUSION

The PLLA membrane is a suitable material to be applied for tissue regeneration in this animal model.

The Use of Tilted Implant for Posterior Atrophic Maxilla

PURPOSE

To retrospectively analyze the influence of implant inclination on marginal bone loss at freestanding implant-supported fixed partial prostheses (FPPs) over a medium-term period of functional loading.

MATERIALS AND METHODS

Twenty-nine partially edentulous patients with freestanding FPDs supported by two implants placed in a two-stage procedure comprised the study group. The anterior implant was placed axially, and the posterior tilted distally. Mesial or distal inclination of each implant was measured in relation to the vertical axis perpendicular to the occlusal plane. Average bone loss was compared between straight and tilted implants, smokers, and nonsmokers.

RESULTS

Mean angulation of the anterior axial-positioned implant was 3.45 degrees distally (range 0-8) and of the distal implants was 32.83 degrees distally (range 20-50 degrees). Average bone loss after 1, 3, and 5 years was 0.89 (SD = 0.73), 1.18 (SD = 0.74), and 1.50 (SD = 0.81), respectively, for axial implants, and 0.98 (SD = 0.69), 1.10 (SD = 0.60) and 1.50 (SD = 0.67) for tilted implants, with no significant correlation between implant angulation and bone loss. A significant correlation between implant angulation and annual bone loss was obtained for tilted implants only (r = 0.52, p = .004).Using Albrektsson criteria, the success rate was 89.6% (26 out of 29 implants) for straight and 93.1% (27 out of 29) for tilted implants.

CONCLUSION

The study demonstrates no effect of implant angulation on peri-implant bone loss in the posterior maxilla.

Insufficient evidence for sinus lifts over short implants for dental implant rehabilitation

DATA SOURCES

The Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase databases were searched with no language or date restrictions.

STUDY SELECTION

Two reviewers independently selected studies. Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that reported the outcome of implant success or failure at least four months after initial loading were considered.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently by two reviewers and study risk of bias assessed. Results were expressed using fixed-effect models as there were either fewer than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small.

RESULTS

Eighteen trials involving 650 patients were included. Five studies were considered to be at low risk of bias, 11 at high risk and two of unclear risk. Four trials (102 patients) evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials).Fourteen trials (548 patients) compared different sinus lift techniques. Only three comparisons included more than one trial. These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet-rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure.The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one- versus two-stage lateral sinus lift, two-stage granular bone versus one-stage autogenous bone blocks and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.

CONCLUSIONS

There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.

Sinus floor elevation outcomes following perforation of the Schneiderian membrane. An experimental study in sheep

OBJECTIVE

To assess the influence of a collagen membrane covering a perforation of the sinus (Schneiderian) membrane on the outcome (bone fill) of a sinus floor elevation.

MATERIALS AND METHODS

Eighteen Pelibuey sheep were used. The animals underwent sinus floor elevation on both sides of the upper jaw. A perforation of 5 × 4 mm in dimension of the sinus mucosa was performed on both sides and, at a randomly selected test site, a collagen membrane was placed to cover the perforation. A graft of biphasic calcium phosphate (60% HA/40% beta-TCP) was subsequently placed bilaterally, and the access window was closed with a membrane made of polylactic acid and a citric acid ester acetyl. The sacrifices were performed after 2, 4, and 12 weeks of healing.

RESULTS

After 2 weeks of healing, the augmented volume was filled with biomaterial surrounded by connective tissue and minimal new bone was detected. After 4 weeks of healing, new bone was found mainly in connection with the sinus bony walls with percentages of 18.0 ± 12.9% at the test and 12.3 ± 7.9% at the control sites. After 12 weeks of healing, similar amounts of newly formed bone were found compared to the previous healing period, namely 16.7 ± 8.0% and 13.7 ± 10.1% at the test and control sites, respectively, with the highest amount detected in the bottom of the sinus cavity. The newly formed bone was distributed more evenly within the sinus cavity also including the central areas. The differences between test and control sites did not reach statistical significance.

CONCLUSION

Even though there were trends for more bone formation when applying a collagen membrane on a sinus mucosal perforation of relatively small dimensions, this study failed to establish the absolute necessity of such a procedure to achieve bone fill in the sinus cavity.

Radiological sinus lift: a new minimally invasive CT-guided procedure for maxillary sinus floor elevation in implant dentistry

PURPOSE

Implant therapy has become an excellent treatment modality as its inception into the modern era of dentistry. However, when patients present with advanced atrophy of the maxillary alveolar ridge, the procedure of choice to restore the anatomic bone deficiency is surgical maxillary sinus floor elevation or sinus lift. The purpose of this study was to describe the CT guided sinus lift technique and to illustrate the minimally invasive aspect of this new radiological procedure called radiological sinus lift.

MATERIAL AND METHODS

For this prospective study, 17 cadaver heads which met our inclusion criteria (edentulous posterior maxillary sector and bone height less than 5 mm) were analyzed using cone beam computed tomography (CBCT) and orthopantomography (OPT). CT and sinus endoscopy was used to guide each step in the procedure. The radiological sinus lift technique consists of the following four stages: Approach. A 14.5 G OstyCut needle was inserted mesial to the canine eminence, and manual drilling was performed parallel to the sinus floor. Osteotomy. An inner obturator with a blunt tip was introduced to compress bone, to push it in close proximity to the sinus membrane and finally to create an osseous window opening into the submucosal space. Lifting. The sinus lift was performed using hydrodissection with dilute iodinated contrast medium. Filling. The submucosal space was then filled with an injection of dilute collagen. Success of the radiological sinus lift procedure was defined by the presence of a dome shape visible within the maxillary alveolar recess. All cases were imaged postoperatively using OPT and maxillary CBCT.

RESULTS

Twelve maxillary sinuses underwent the radiological sinus floor elevation procedure. A dome shape of the Schneiderian membrane was achieved in eight maxillary sinuses (66.7%). All failures (n = 4) were caused by mucosal perforation at the time of maxillary sinus osteotomy. Mean height of membrane elevation was 12.0 mm, with a mean intervention time of 45 min.

CONCLUSION

This experimental study evaluates a new minimally radiological procedure for maxillary sinus floor elevation, which provides an interventional radiological alternative to the classical surgical lateral approach and achieves an equivalent success rate to that cited in the literature for the surgical approach, a low morbidity and a shorter operating time.

Maxillary sinus augmentation

Pneumatization of the maxillary sinus secondary to posterior maxillary tooth loss is an extremely common finding. Significant atrophy of the maxilla prevents implant placement in this region. For several decades, sinus augmentation has been used to develop these sites for dental implant placement. The main techniques for increasing the vertical bone height of the posterior maxilla are the transalveolar and lateral antrostomy approaches. The clinical and radiographic examinations dictate the appropriate method for each clinical situation. Both techniques have been shown to have high success rates. However, practitioners must be aware of potential complications and how to address them.

Incremental, transcrestal sinus floor elevation with a minimally invasive technique in the rehabilitation of severe maxillary atrophy. Clinical and histological findings from a proof-of-concept case series

In the posterior maxillary sextants, the residual dimensions of the edentulous ridge can considerably limit the insertion of implants with the desired length and diameter. A minimally invasive procedure for transcrestal sinus floor elevation (tSFE), namely the Smart Lift technique, which is based on a standardized sequence of specifically designed drills and osteotomes, was introduced in 2008 and subsequently validated in a series of recent studies. The present technical note describes the use of the technique by a staged approach, called incremental tSFE (i-tSFE), in the augmentation of severely resorbed edentulous ridges. The i-tSFE consists of 2 staged tSFE procedures performed with a transcrestal access, the second of which is performed concomitantly with implant placement. In the present case series, 3 patients with severe bone atrophy (residual bone height, 2 to 3 mm) in the edentulous posterior maxilla were treated with i-tSFE. At the second surgical stage of i-tSFE, implants at least 8 mm long were placed at all sites, and the success of the implant-supported restoration was monitored to 6 months (1 patient) or 3 years (2 patients). Histologic findings from an augmented site showed the presence of newly formed bone, bone marrow spaces with numerous vascular canals, and residual graft particles occupying approximately 50%, 15%, and 35% of the total area, respectively. The results of the study showed that i-tSFE can be performed successfully with the Smart Lift technique to rehabilitate atrophic maxillary posterior sextants.

Graftless sinus augmentation technique with contextual placement of implants: a case report

INTRODUCTION

The positioning of implants in the jaw bones with contextual graftless lateral approach sinus lifting is finding an increasingly broad consensus in the literature. Since the 1970s, various clinical research projects have been conducted on applications of biological and synthetic biomaterials in bone regenerative surgery, both in sinus lift procedures and in cystic cavity filling after cystectomy or in bone defects in regenerative periodontal surgery. Currently, we are finding that there is an increasing trend of clinicians aiming to adopt graftless techniques, with satisfactory results in terms of implant survival in the long term. In our study, through a case report, we describe a variant of graftless sinus augmentation technique with contextual implant placement, emphasizing the role of the blood clot, combined with collagen sponges, as a natural scaffold and the osteogenic potential of the subantral membrane in guided bone regeneration, with reduced morbidity of the patient.

CASE PRESENTATION

To describe the surgical technique, the clinical case of a 38-year-old Caucasian woman with a lateral posterior edentulism was selected. The rehabilitation was solved by a graftless sinus augmentation technique with a contextual implant placement. For each implant, a resonance frequency analysis evaluation was reported as implant stability quotient values. The performance of the implant stability quotient values followed a gradual increase from time zero to the sixth month, as the clot was differentiated into osteoid tissue and then into bone tissue, due to the scaffold effect conferred by the equine collagen sponge. The stabilization phase took place between the fourth and the sixth month, according to the implant stability quotient values.

CONCLUSIONS

Our graftless sinus augmentation technique seems to be very predictable thanks to the osteoconductive principles on which it is based, and in association with the proper management of peri-implant soft tissue, so as to increase the amount of keratinized tissue, which could represent the new gold standard for this type of rehabilitation in the future.

Evaluation of anatomical considerations in the posterior maxillae for sinus augmentation

The edentulous posterior maxilla is considered a clinical challenge during dental implant treatment for many dental practitioners. This is because its insufficient bone quality, deficient alveolar ridge, spiny ridges, undercuts, and sinus pneumatization are often encountered after tooth loss. To overcome these problems, several approaches have been developed and are currently used, including sinus augmentation and bone augmentation. Today, two main procedures of sinus floor elevation for dental implant placement are in use: a two-stage technique using the lateral window approach, and a one-stage technique using a lateral or a crestal approach. In this study, we deal with the anatomic relations of the structures of the maxillary sinus during sinus augmentation. These anatomical findings can help in complications and potential injuries of the maxillary sinus procedures. It can be suggested that pre-operative evaluation is helpful for diagnosis and treatment planning and minimizing complication during the surgery.

Paradigm shift in the management of the atrophic posterior maxilla

When the posterior maxilla is atrophic, the reference standard of care would be to perform sinus augmentation with an autologous bone graft through the lateral approach and delayed implant placement. However, placement of short implants with the osteotome sinus floor elevation technique and without graft can be proposed for an efficient treatment of clinical cases with a maxillary residual bone height of 4 to 8 mm. The use of grafting material is recommended only when the residual bone height is ≤4 mm. Indications of the lateral sinus floor elevation are limited to cases with a residual bone height ≤ 2 mm and fused corticals, uncompleted healing of the edentulous site, and absence of flat cortical bone crest or when the patient wishes to wear a removable prosthesis during the healing period. The presented case report illustrates osteotome sinus floor elevation with and without grafting and simultaneous implant placement in extreme conditions: atrophic maxilla, short implant placement, reduced healing time, and single crown rehabilitation. After 6 years, all placed implants were functional with an endosinus bone gain.

Nasal Floor Elevation for Implant Treatment in the Atrophic Premaxilla: A Within-Patient Comparative Study

BACKGROUND

There is a lack of evidence regarding success of implants placed in atrophic premaxilla using the nasal floor elevation technique.

PURPOSE

This study aimed to compare implants placed in augmented bone in the anterior maxilla using the nasal floor elevation technique with implants placed in the maxillary sinus region using the sinus lift technique.

MATERIALS AND METHODS

A within-patient controlled clinical trial was performed on 14 patients receiving 78 implants. The implants were assigned to one of two study groups on the basis of implant location. A total of 37 implants were placed in the nasal fossa region (NF group), and 41 implants were placed in the maxillary sinus region (MS group). Patients were followed up for 4.5 ± 2.2 years, with comparable follow-up times for implants in NF and MS groups (4.7 ± 2.1 and 4.9 ± 2.1 years, respectively; p > .05). Treatment outcomes were assessed and statistically analyzed.

RESULTS

Implant success rate was 89.2% in the NF group and 95.0% in the MS group, with no statistically significant difference between them (p > .05). No nasal or sinus membrane perforation or other complications were reported within the follow-up period. Significant differences were found between the two groups in terms of residual bone height, augmented bone height, and implant diameter.

CONCLUSIONS

Nasal floor elevation is an effective and safe procedure that can be used for implant placement in atrophic premaxilla with success rates that are comparable to those of implants placed in the maxillary sinus.

Impact of human maxillary sinus volume on grafts dimensional changes used in maxillary sinus augmentation: a multislice tomographic study

PURPOSE

To assess the influence of complete maxillary sinus volume on the dimensional changes of different grafts used in maxillary sinus lift.

MATERIALS AND METHODS

Analysis of 50 surgical procedures of maxillary sinus lift performed on 43 subjects using different grafting materials: fresh frozen allogenic particulated bone (11), hydroxyapatite (Endobon(®)) (17), 60% hydroxyapatite + 40% beta-tricalcium phosphate (Bone Ceramic(®)) (12) and Bone Ceramic(®) + Emdogain(®) (10). One hundred and fifty multislice tomographic images of the maxillary sinus were obtained using the software Syngo CT 2011 A VOLUME, measuring complete maxillary sinus volume (T0) and dimensional changes of different graft materials during periods of 15 days (T1) and 180 days (T2). The factor studied was the influence of maxillary sinus volume on the dimensional changes of different graft materials used in maxillary sinus lift in patients with posterior edentulism. Data obtained were assessed using the Student's t-test and Pearson's correlation coefficient.

RESULTS

No correlation (r 0.112) between the total maxillary sinus volume and the dimensional changes of the different graft materials used in this study was observed (P > 0.05).

CONCLUSION

This study demonstrated that there is no sufficient evidence to support the thesis that the volume of the maxillary sinus influences the contraction of the grafts, at least on sample or the biomaterials evaluated in this cohort study.

Recent Trends in Sinus Lift Surgery and Their Clinical Implications

BACKGROUND

Sinus lift procedures are used to allow residual bone to accommodate functional implants in atrophic posterior maxilla. Numerous anatomical and surgical advancements in sinus lift surgery are still inspiring clinicians.

PURPOSE

The purpose of this study was to describe the recent trends in sinus lift surgery focusing on implant survival, bone grafting, anatomical and surgical considerations, and their clinical implications on the practice of implant dentistry in atrophic posterior maxilla.

MATERIALS AND METHODS

We performed an extensive search in MEDLINE, Embase, Scopus, Web of Science, Trip, Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials, and ProQuest Dissertations & Theses. Articles were critically reviewed to determine the level of evidence as per the Canadian Task Force on Preventive Health Care.

RESULTS

Comprehensive assessment of sinus septa, sinus pathology, and bone quality and quantity using three-dimensional cone beam computed tomography radiographs is important before placing implants in posterior maxilla. With a residual bone height of less than 5 mm, the survival rate of implant decreases substantially. Lateral window approach can increase the vertical bone height to greater than 9 mm, while osteotome approach can increase this height from 3 to 9 mm. The perforation of Schneiderian membrane doubles the risk for the incidence of sinusitis or infection. The use of piezoelectric surgery allows adequate sinus lift while protecting soft tissues and minimizing patient discomfort.

CONCLUSIONS

Although both osteotome and lateral window procedures can help clinicians in overcoming the challenges of placing implants in atrophic posterior maxilla, pre-implant residual bone height is crucial in determining the survival of these implants. Future research directions should consider study designs grounded on longitudinal randomized controlled trials of large sample size.

Coalescence of inter: Osteotomy bone graft material inserted via separate transcrestal sinus osteotomies: A case report and concise review of the literature

When multiple implants are to be placed, and a pneumatized sinus exists, the published reports suggest that the lateral window approach (LWA) is favored for sinus floor augmentation. Simultaneously, if a transcrestal sinus floor augmentation has been carried out (bone-added osteotome sinus floor elevation), the reports are restricted to single implant placement at any site. The aim of this study was to evaluate the clinical and radiographic outcomes at adjacent transcrestal sinus augmentation grafts using deproteinized bovine bone material, with the immediate placement of submerged adjacent implants, and so determining the fate of the graft material. The progressive loss of the inter-implant graft is reported for the LWA Technique. However, this novel coalescence method has shown a progressive increase in the inter-implant graft region, thus inferring a positive bony regeneration and remodelling at the region. These results indicate that the carrying out of a large scale study is warranted to confirm the efficacy of this technique.

Preoperative implant planning considering alveolar bone grafting needs and complication prediction using panoramic versus CBCT images

Purpose

This study was performed to determine the efficacy of observers' prediction for the need of bone grafting and presence of perioperative complications on the basis of cone-beam computed tomography (CBCT) and panoramic radiographic (PAN) planning as compared to the surgical outcome.

Materials and Methods

One hundred and eight partially edentulous patients with a need for implant rehabilitation were referred for preoperative imaging. Imaging consisted of PAN and CBCT images. Four observers carried out implant planning using PAN image datasets, and at least one month later, using CBCT image datasets. Based on their own planning, the observers assessed the need for bone graft augmentation as well as complication prediction. The implant length and diameter, the need for bone graft augmentation, and the occurrence of anatomical complications during planning and implant placement were statistically compared.

Results

In the 108 patients, 365 implants were installed. Receiver operating characteristic analyses of both PAN and CBCT preoperative planning showed that CBCT performed better than PAN-based planning with respect to the need for bone graft augmentation and perioperative complications. The sensitivity and the specificity of CBCT for implant complications were 96.5% and 90.5%, respectively, and for bone graft augmentation, they were 95.2% and 96.3%, respectively. Significant differences were found between PAN-based planning and the surgery of posterior implant lengths.

Conclusion

Our findings indicated that CBCT-based preoperative implant planning enabled treatment planning with a higher degree of prediction and agreement as compared to the surgical standard. In PAN-based surgery, the prediction of implant length was poor.

Long-term survival rate of implants placed in conjunction with 246 sinus floor elevation procedures: results of a 15-year retrospective study

OBJECTIVES

The aim of the present long-term study was to retrospectively evaluate the survival rate of implants placed in regenerated maxillary sinuses and to assess the influence of hypothetical predictors of implant failure.

METHODS

A database including 218 patients who received dental implants after sinus lift procedures was analyzed. The following variables were systematically included and evaluated: type of graft material used, number of surgeries performed, and use of membranes to cover the lateral antrostomy and/or to repair accidental Schneiderian membrane perforations. The Kaplan-Meier estimator was used for comparisons among the groups.

RESULTS

A total of 589 dental implants were positioned in 246 grafted sinuses and were in function for 3-186 months. The Kaplan-Meier cumulative survival rate was 98.3% after 15.5 years of follow-up. All implant losses occurred within 52 months (4.3 years) after augmentation. According to the log-rank test, no statistically significant difference was shown between each patient/implant variable (p>0.05).

CONCLUSIONS

Despite the limitations inherent in this type of study, no statistically significant differences between the groups could be found. Intraoperative Schneiderian membrane perforations did not affect the outcome of the implants positioned.

CLINICAL SIGNIFICANCE

The present long-term study is intended as a reference for clinicians approaching sinus floor elevation surgery in order to provide them with relevant operative findings. Since all the drawbacks occurred within the first 5 years, medium-term follow-up studies could be suitable for further retrospective evaluations.

Prevalence of maxillary sinus pathology in patients considered for sinus augmentation procedures for dental implants

PURPOSE

To determine the prevalence of maxillary sinus pathology in patients presenting for implant rehabilitation involving sinus augmentation procedures.

MATERIALS AND METHODS

Three-dimensional images of 275 patients were evaluated. Age and gender were recorded to see if they had any relationship to the prevalence of pathology. Scans were classified into 1 of the 5 categories based on the type of sinus pathology detected: healthy, mucosal thickening > 5mm, polypoidal mucosal thickening, partial opacification and/or air fluid level, and complete opacification.

RESULTS

Overall, 54.9% scans were classified as healthy, and 45.1% scans were classified as exhibiting sinus pathology. Men were more likely to exhibit pathology compared with females (P < 0.01). However, age did not seem to have any relation on the prevalence of sinus pathology. Of the patients who presented with evidence of sinus pathology, 56.5% had mucosal thickening (≥ 5 mm), 28.2% with polypoidal thickening, 8.9% partial opacification and/or air/fluid level, and 6.5% complete opacification.

CONCLUSIONS

It is proposed that, based on the findings of this study, 45.1% patients would require further consultation before proceeding with maxillary sinus augmentation surgery.

Sinus Width Analysis and New Classification with Clinical Implications for Augmentation

PURPOSE

To measure the distances between the medial and lateral sinus wall (sinus width [SW]) at different levels on cone beam computed tomography (CBCT) and apply those SW values to formulate a new sinus classification.

MATERIALS AND METHODS

Edentulous sites adjacent to maxillary sinuses with inadequate residual bone height (RBH) were included from the CBCT database. SW was measured at the heights of 1, 3, 5, 7, and 9 mm from the sinus floor. Mean SW was stratified into different groups by RBH, study sites (first and second premolars and molars), and measurement levels. Statistical analyses were conducted with commercially available software (IBM SPSS Statistics 19, SPSS Inc., Chicago, IL, USA).

RESULTS

A total 186 patients (mean age 50.4 years) with 267 edentulous sites were included. Mean SW was wider at molar sites, higher measurement levels, and sites with less RBH. Narrow, average, or wide sinuses were classified based on the 33rd and 67th percentile SW values at 1-, 5-, and 9-mm measurement levels, respectively.

CONCLUSIONS

SW at different levels relating to sinus floor elevation was measured. The proposed classification could contribute to estimate the difficulty of sinus augmentation, useful for the selection of surgical approaches. Further studies are required to testify its clinical implications.

Effect of maxillary sinus floor augmentation without bone grafts

Objective:

The objective of the present review was to determine the effectiveness of maxillary sinus floor augmentation without bone grafts using lateral window technique.

Materials and Methods:

PubMed and Cochrane databases were searched for relevant articles. We also included articles by hand search until June 2012. The analysis included both human and animal studies which satisfied the following criteria: Minimum of 6 months follow-up, no use of bone grafts, and lateral window approach to the sinus.

Results:

We included 22 articles in the review. A descriptive analysis of the constructed evidence tables indicated that there is evidence of predictable a mount of bone formation in the maxillary sinus augmentation without the use of bone grafts.

Conclusion:

Within the limits of the articles and data available, maxillary sinus augmentation without bone graft might be considered effective inpredictable bone formation.

The influence of sinus membrane thickness upon membrane perforation during transcrestal sinus lift procedure

OBJECTIVES

Schneiderian membrane perforation is one of the main complications during sinus augmentation. The reasons may be associated with surgical technique, septum, inadequate ridge height, and membrane thickness. However, reports that used cone-beam computed tomography (CBCT) to quantify the thickness of sinus membrane were limited. The aims of this retrospective study were: to study the correlation between membrane thickness and perforation rate during transcrestal sinus lift and to propose a classification system of sinus membrane thickness based upon CBCT data.

MATERIAL AND METHODS

One hundred and twenty-two subjects who received dental implant restorations over posterior maxilla with a total of 185 transcrestal sinus lift procedures between years 2010 to 2013 were selected consequently. Each patient selected had to have taken CBCT in the initial examination and immediately after surgery. The membrane thickness, perforation rate, residual bone height, and elevated bone height were recorded and processed for statistical analysis.

RESULTS

The mean thickness of the Schneiderian membrane was 1.78 ± 1.99 mm. There was a significant correlation between membrane thickness and perforation rate (P < 0.05), and the perforation rate was higher in thicker (≥3 mm) and thinner membrane (≤0.5 mm). Among the thickness group, Class B (between ≥1 and <2 mm) had the lowest perforation rate. No significant difference was between the perforation and the membrane morphology. A negative relationship between residual bone height and membrane thickness was found. Trend showed that in the thicker and the thinner residual bone height, the higher the perforation rate would be.

CONCLUSIONS

There was a significant correlation between membrane thickness and perforation rate. The perforation rate was lowest when the thickness was 1.5-2 mm.