Maxillary Sinus Membrane Elevation Research Articles

Endo-sinus bone gain following sinus membrane elevation without graft compared with sinus floor augmentation and a composite graft: a one-year single-blind randomized controlled trial

The objective of this study was to assess endo-sinus bone gain (ESBG) and bone density (BD) following maxillary sinus membrane elevation without graft (test) compared with maxillary sinus floor augmentation and 1:1 ratio of autogenous bone from the buccal antrostomy and deproteinized porcine bone mineral (control) using two- and three-dimensional radiographic methods. Forty healthy patients were randomly allocated to the test and control groups. Cone beam computed tomography scans were obtained at enrolment (T0), immediately after surgery (T1), at delivery of the prosthetic rehabilitation (T2), and 1 year after functional implant loading (T3). Mean differences were expressed with the 95% confidence interval. Significance was set at ≤ 0.05. ESBG and BD were significantly higher in the control group than test group at T1, T2, and T3 (P < 0.001). A significant decrease in ESBG and increase in BD was observed from T1 to T3 with both treatments (P < 0.001). There was a non-significant positive correlation of ESBG with implant protrusion length and non-significant negative correlation with residual bone height. In conclusion, test was associated with significantly lower ESBG and BD compared with control. However, the lower ESBG and BD did not appear to negatively affect the implant stability quotient or implant treatment outcome after 1 year of functional implant loading.

Maxillary sinus membrane elevation and coagulum compared with maxillary sinus floor augmentation and a composite graft: A 1-year single-blinded randomized controlled trial.

The aim was to evaluate the 1-year implant outcome and patient-related outcome measures (PROMs) after maxillary sinus membrane elevation and coagulum (test) compared with maxillary sinus floor augmentation and a 1:1 ratio of autogenous bone graft from the buccal antrostomy and deproteinised porcine bone mineral (DPBM) (control). Forty patients (30 female, 10 male) with a mean age of 50 years (range 25-71 years) and an alveolar ridge height between 4 and 7 mm were randomly allocated to test or control. Outcome measures included survival of suprastructures and implants, implant stability quotient, health status of the peri-implant tissue, peri-implant marginal bone loss, frequency of complications and PROMs using Oral Health Impact Profile-14 combined with questionnaires assessing patient's perception of the peri-implant soft tissue, implant crown, function of the implant, and total implant treatment outcome using visual analogue scale. Mean differences were expressed with standard deviation and 95% confidence interval. Level of significance was 0.05. All suprastructures and implants were well-functioning after 1-year of functional implant loading. No significant difference in any of the applied outcome measures was observed between test and control. Both treatments revealed high patient satisfaction scores and significant improvement in oral health-related quality of life. There were no significant differences in implant outcome and PROMs between test and control, after 1-year of functional implant loading. Neither of the treatments can therefore be considered better than the other. Thus, long-term randomized controlled trials are needed before definitive conclusions can be provided about the two treatment modalities.

Lateral approach sinus (LAS) and crestal approach sinus (CAS): The unravelled paraphernalia for maxillary sinus membrane advancement

The permanent replacement of missing teeth in the maxillary posterior tooth region becomes a tedious task when it is confounded with bone atrophies. To overcome this problem and achieve successful rehabilitation, maxillary sinus membrane elevation procedures have been advocated as the most reliable means. The lateral window technique and the crestal approach are two of the most common approaches. These technologically developed procedures have reported high success rates in cases of deficient residual bone. Over time, there have been many advancements in these techniques that led to the development of user-friendly kits like the Lateral approach Sinus (LAS) kit and the Crestal approach Sinus (CAS) kit. In this case series, we have reported two cases, treated with either of these approaches and have compared the same. We aim at highlighting their ease of application in the clinical field and the promising results obtained with their use. Our clinical experience disclosed that maxillary sinus membrane advancement using both the kits have proven to be a reliable technique for implant placement in sites where insufficient bone is available.

Patient's perception of recovery after sinus membrane elevation and blood coagulum compared with 1:1 mixture of autogenous bone graft and deproteinized porcine bone mineral. Secondary outcomes from a single-blinded randomized controlled trial.

The objective was to assess patient's perception of recovery after maxillary sinus membrane elevation (MSME) and blood coagulum (test) compared with maxillary sinus floor augmentation (MSFA) and 1:1mixture of autogenous bone graft from the buccal antrostomy and deproteinized porcine bone mineral (DPBM) (control). Forty healthy patients were randomly allocated to test or control. Oral health-related quality of life (OHRQoL) was evaluated by Oral Health Impact Profile-14 (OHIP-14) at enrollment and 1week postsurgical. Recovery was estimated by questionnaires and visual analog scale assessing pain, social and working isolation, physical appearance, eating and speaking ability, diet variations, sleep impairment, and discomfort after 1week and 1month. Mean differences were expressed with 95% confidence interval (CI). Association between OHRQoL and recovery was estimated. p-value below .05 was considered statistically significant. Maxillary sinus membrane elevation revealed 2.1less days of pain (p=.03, 95% CI: 0.2-4.1) and 1.2days of sick leave (p=.01, 95% CI: 0.3-2.1) compared with MSFA. No significant difference was observed in eating and speaking ability, physical appearance, work performance, and sleep impairment. No significant association between impaired OHRQoL and recovery was observed. Females reported 4.77higher OHIP-14score compared with males (p=.01, 95% CI: 1.60-7.94), while association between age and OHIP-14 was -0.10 (p=.28, 95% CI: -0.28 to 0.08). Maxillary sinus membrane elevation revealed significantly less days of pain and sick leave compared with MSFA. Harvesting of autogenous bone graft seems, therefore, to have a significant impact on perception of recovery.

Effect of Buccal Fat Pad and Platelet Rich Fibrin After Ultrasonic Hydrodynamic Maxillary Sinus Membrane Elevation

Effect of Buccal Fat Pad and Platelet Rich Fibrin After Ultrasonic Hydrodynamic Maxillary Sinus Membrane Elevation

Blood clot stability and bone formation following maxillary sinus membrane elevation and space maintenance by means of immediate implant placement in humans: A computed tomography study

Abstract Objective The present controlled clinical pilot study proposed to assess blood clot contraction and bone neo-formation following maxillary sinus lift (MSL) with immediate implant placement without using grafts using cone beam tomography exams. Materials and methods Ten implants were placed in ten patients with a residual bone crest height ≥4 and ≤ 7 mm, in maxillary premolars or 1st or 2nd molars regions, using MSL and immediate implant placement without grafts, by means of the lateral window approach. A resorbable membrane (Bio-Gide®, Geistlich, USA) was used to close the window. Computed tomography images were taken after 15 (T1) and 180 (T2) days to assess the rate of blood clot contraction and bone neo-formation. The images were analysed by OsirixMD software. The Shapiro Wilk test was used to verify the normality hypothesis and the data were submitted to Student's paired t-test. Results The mean of bone clot height in mesial, apical and distal area referred to implant, presented 4.77 mm, 0.77 mm and 5.30 mm respectively. The mean measurements of new bone formation presented 2.95 mm, 0.44 mm and 3.45 mm. The height contraction (coagulum/new bone formation), between T1 and T2, presented 38%, 43% and 35% respectively, with a significant statistical value p The volume measurements at T1 presented a mean volume of 0.90 cm3 sd ± 0.60 cm3 and at T2 a mean volume of 0.75 cm3 sd ± 0.62 cm3, with a significant volume contraction between T1 and T2, p Conclusion The present study demonstrates consistent bone formation around all assessed implants, although with significant contraction of the blood clot. The need for longitudinal studies to establish a long-term prognosis in different modalities of prosthetic rehabilitation of those implants is strongly suggested.

Clinical evaluation of two transalveolar methods for sinus augmentation with placing 1 204 implants immediately

Objective: To compare the clinical outcomes of posterior maxillary implant surgery when using the regular transalveolar approach or with the crestal approach-sinus (CAS-KIT), a device for maxillary sinus membrane elevation by the crestal approach using a special drilling system and hydraulic pressure. Methods: In this retrospective study 887 patients during Jan 2012 to July 2015 in Hangzhou Dental Hospital with underwent either regular transalveolar approach or CAS-KIT approach for maxillary augmentation; whereas 11 patients dropped out for the reason of serious membrane perforations. Totally, 876 patients with 1 204 plants, placed immediately after transalveolar maxillary augmentation, were included in this study. The data analysis was performed by radiological measures to assess the changes in height of maxillary sinus floor after the transalveolar augmentation at different time points. In addition, the complications after surgery, failure rates, osseointegration condition and the performance of rehabilitation were evaluated as well. Results: Five hundred and three patients were experienced with regular transalveolar approach, and 7 patients were drop out for the serious membrane perforations. Thus, 496 patients received 653 implants in this group; the average lifted range in maxillary sinus floor height changes was (4.08±3.45) mm. The complications were minor membrane perforations during procedure in 64 patients, postoperative maxillary sinus infection happening in 2 patients and 13 patients experienced rehabilitation failure. Three hundred and eighty-four patients had CAS-KIT approach with 4 patients dropped out. Three hundred and eighty patients get 551 implants with the mean lifted range of (8.36±4.07) mm in maxillary sinus floor height changes. Minor membrane perforations during procedure occurred in 31 people and 2 got postoperative maxillary sinus infection. The 4 year overall survival rate of 1 204 implants was 97.26%, with four implants fell off after 3 months of rehabilitation and one implant occurred after one year of rehabilitation. Conclusions: The regular transalveolar sinus lift technique is easier and time saving, but the compromised lifting range in maxillary sinus floor height and the comparatively high occurrence of intraoperative membrane perforations should be concerned. Using CAS-KIT could be an alternative method to perform maxillary sinus augmentation with a reduced incidence of complications. There was no statistically difference in implant failure rates and incidence of postoperative maxillary sinus infection between two groups.

Blood clot stability and bone formation following maxillary sinus membrane elevation and space maintenance by means of immediate implant placement in humans. A computed tomography study

ObjectiveThe present controlled clinical pilot study proposed to assess blood clot contraction and bone neo-formation following maxillary sinus lift (MSL) with immediate implant placement without using grafts using cone beam tomography exams. Materials and methodsTen implants were placed in ten patients with a residual bone crest height ≥4 and ≤ 7 mm, in maxillary premolars or 1st or 2nd molars regions, using MSL and immediate implant placement without grafts, by means of the lateral window approach. A resorbable membrane (Bio-Gide®, Geistlich, USA) was used to close the window. Computed tomography images were taken after 15 (T1) and 180 (T2) days to assess the rate of blood clot contraction and bone neo-formation. The images were analysed by OsirixMD software. The Shapiro Wilk test was used to verify the normality hypothesis and the data were submitted to Student's paired t-test. ResultsThe mean of bone clot height in mesial, apical and distal area referred to implant, presented 4.77 mm, 0.77 mm and 5.30 mm respectively. The mean measurements of new bone formation presented 2.95 mm, 0.44 mm and 3.45 mm. The height contraction (coagulum/new bone formation), between T1 and T2, presented 38%, 43% and 35% respectively, with a significant statistical value p < 0.05.The volume measurements at T1 presented a mean volume of 0.90 cm3 sd ± 0.60 cm3 and at T2 a mean volume of 0.75 cm3 sd ± 0.62 cm3, with a significant volume contraction between T1 and T2, p < 0.005. The mean blood clot contraction was 16.52% ± 8.60%. ConclusionThe present study demonstrates consistent bone formation around all assessed implants, although with significant contraction of the blood clot. The need for longitudinal studies to establish a long-term prognosis in different modalities of prosthetic rehabilitation of those implants is strongly suggested.

EVALUATION OF EFFICIENCY AND SAFETY OF PIEZOSURGERY VERSUS CONVENTIONAL ROTARY INSTRUMENTS IN LATERAL MAXILLARY SINUS FLOOR ELEVATION: A PROSPECTIVE RANDOMIZED CONTROLLED CLINICAL TRIAL

To overcome the intra and post-operative complications that might arise during the use of theconventional instruments for cutting the bony window and elevation of maxillary sinus membrane,the application of ultrasonic device (piezosurgery) has been introduced.Aim of the study: To evaluate the efficiency and safety of the piezosurgery during direct sinuslifting procedure in comparison to the conventional rotary instruments.Patients and methods: A randomized controlled clinical trial was performed, in which fortypatients (17 females and 23 males) with bone height of less than 3 mm in the posterior maxilla, whorequired implant placement to replace the missing teeth, were selected. The sinus lift surgeries weredone either by the piezosurgery or the conventional bur technique. The rate of perforation, time ofthe operation, healing, postoperative edema, and pain were evaluated. Six months later, implantswere placed within the augmented sites.Results: A lower percentage of membrane perforation has been encountered in the piezosurgerygroup (5% one patient), when compared to the conventional group (15%, three patients).The painand swelling were significantly less in the piezosurgery group but the mean time was longer in thepiezosurgery group .Conclusion: The piezosurgery is an effective device that is safer in performing the lateralmaxillary sinus lift surgery than the conventional rotary method, but unfortunately it takes longeroperation time.

Maxillary Sinus Membrane Elevation Using a Special Drilling System and Hydraulic Pressure: A 2-Year Prospective Cohort Study.

The purpose of this study was to evaluate clinical and radiologic outcomes using a newly developed device for maxillary sinus membrane elevation. Patients with a residual bone height of at least 3 mm were enrolled. Crestal sinus lift elevation and sinus graft were performed using the crestal approach sinus (CAS) kit. Graft was avoided if the residual bone crest was ≤ 2 mm less than the length of the planned implant. Outcome measures were implant and prosthesis failure, any biologic or technical complications, and marginal bone loss (MBL). A total of 35 consecutive patients underwent 49 crestal elevations of the sinus membrane. All the implants were followed for at least 2 years after placement (mean follow-up 37.3 months; range 24 to 54 months). No implants or prostheses failed during follow-up, and no membrane tears or other intraoperative or postoperative adverse events were observed. At the 2-year follow-up, mean MBL was 0.33 ± 0.24 mm (95% confidence interval: 0.08 to 0.30 mm). A total of 32 implants were placed after filling the sinus with anorganic bovine bone, while 17 implants were placed without grafting the sinus. Post-hoc analysis was performed using the sinus grafting remodeling index (SGRI) to evaluate radiographically the tissue remodeling patterns. The SGRI was statistically significantly higher when the sinus was grafted (P = .000). The CAS kit may provide a new option for minimally invasive crestal sinus surgery. Long-term randomized controlled trials with larger sample size are needed to confirm these preliminary results.

Alveolar Crestal Approach for Maxillary Sinus Membrane Elevation with

Introduction For maxillary sinus membrane elevation (MSME), the lateral window approach and crestal approach are available, and high success rates have been achieved with low residual bone height as a development of technology. Objective To evaluate MSME using the crestal approach with a rotary-grind bur (RGB (including reamer or sinus bur)) in patients with residual bone height of <4 mm. Materials and Methods Ten implants were placed in 10 patients with residual bone height of <4 mm, by sinus elevation using an RGB. The implant stability quotient (ISQ) was measured immediately after implant placement (ISQ 1) and before taking impression for the final prosthesis (ISQ 2). The extent of marginal bone loss was measured on periapical radiographs. Results The mean residual bone height before implant placement was 3.41 ± 0.53 mm; no complications, including membrane perforation, severe postoperative pain, or discomfort, occurred either during or after surgery. The mean ISQ 1 was 63.4 ± 12.1, whereas the mean ISQ 2 was 77.6 ± 5.8. The mean marginal bone resorption was 0.23 ± 0.18 mm on periapical radiographs. Conclusions MSME using the crestal approach with an RGB is a reliable technique for implant placement in sites where available bone is insufficient.

Histological analysis of the use of biphasic ceramics based on hydroxyapatite and β-tricalcium phosphate in maxillary sinus floor elevation surgery: pilot study

Abstract Objective To evaluate the bone repair associated with the use of biphasic ceramics based on hydroxyapatite and β-tricalcium phosphate (HA/TCP) in the procedures of maxillary sinus membrane elevation in human beings. Material and method Ten patients with a residual bone ridge in the posterior maxillary region between 3 mm and 5 mm in height were selected and indicated for procedures of bone grafting associated with maxillary sinus lift procedure. The maxillary sinuses were filled with HA/TCP, and after 8 months, the implants were implanted and a bone biopsy was collected with the aid of a trephine drill, which was then submitted to histological analysis for the evaluation of the composition of the grafted area. Result The histological description analysis of the biopsies revealed the presence of vital and immature bone tissue, juxtaposed to the biomaterial. Histomorphometric analysis showed that the biopsy composition was in average 28.8%, 27.4%, and 43.6% of bone tissue, biomaterial, and soft tissue, respectively. Conclusion The areas grafted with HA/TCP presented the adequate amount of bone formation that allowed the implantation of the implants. The success of the grafting procedure with this biomaterial was associated with its osteoconduction potential that allowed the formation of bone tissue in close contact with HA/TCP.

A newly developed device for maxillary sinus membrane elevation by crestal approach: a 2‐year prospective comparative case series study with or without graft material for sinus augmentation

A newly developed device for maxillary sinus membrane elevation by crestal approach: a 2‐year prospective comparative case series study with or without graft material for sinus augmentation

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.

Maxillary Sinus Membrane Elevation With Simultaneous Installation of Implants Without the Use of a Graft Material: A Systematic Review.

To compare implant treatment outcome after maxillary sinus membrane elevation with simultaneous installation of implants with or without the use of graft material applying the lateral window technique. MEDLINE/PubMed, Cochrane Library, and Embase search in combination with a hand-search of relevant journals was conducted from January 1, 2004 to January 1, 2016. Thirteen studies fulfilled the inclusion criteria. Survival of suprastructures has not been compared within the same study. Short-term implant survival without graft material varied between 96% and 100% compared to 100% for autogenous bone or bone substitutes. No significant difference in bone gain was reported without graft material compared to autogenous bone. The density of newly formed bone increased significantly during the observation period. Bone density was significantly higher in sinuses augmented with blood clot compared to bone substitute, whereas no significant difference was found when compared to autogenous bone. Noncomparative studies demonstrated high long-term implant survival and new bone formation after sinus membrane elevation without graft material. Sinus membrane elevation without the use of a graft material seems to enhance new bone formation with high implant survival, but long-term comparative studies are missing.

Sinus Membrane Elevation by the Crestal Approach Using a Novel Drilling System.

The purpose of this study was to evaluate the clinical outcomes of patients undergoing sinus membrane elevation by a minimally invasive crestal approach using a novel drilling system. From May 2008 to November 2009, 21 implants were placed in 19 patients (10 men and 9 women) ranging from 23 to 69 years of age (average of 49.5 years). Implants were placed in maxillary premolar and molar areas that demonstrated insufficient residual bone quality; maxillary sinus membrane elevation was performed using a crestal approach with the sinus crestal approach kit (Neobiotech, Seoul, Korea). There was no sinus perforation or osseointegration failure. The implant survival rate was 100%. The postsurgical, augmented volume of the alveolar height ranged from 2 to 9.2 mm (average of 5.81 ± 2.06 mm). Six months after maxillary sinus elevation, the bone reduction volume ranged from 0.06 to 1.42 mm (average of 0.6 ± 0.38 mm). At final F/U, the amount of bone-height reduction ranged from 0.06 to 2.60 mm (average of 0.82 ± 0.63 mm). Sinus membrane elevation by the crestal approach using special reamers is advantageous because of the noticeable reduction in the risk of perforation and the ability to perform the surgery rapidly.

Association Between Bone Graft Volume and Maxillary Sinus Membrane Elevation Height.

Maxillary sinus augmentation via crestal approach has been advocated as an alternative approach for sinus membrane elevation. Presently, no study has examined the relationship between the amount of bone grafting material placed and the final sinus membrane elevation height. Therefore, the present study was aimed at investigating the extent of sinus membrane elevation height depending on the amount of bone grafting material inserted as well as three-dimensionally assessing the likelihood of membrane perforation during membrane elevation. A total of 34 subjects (16 females and 18 males) with 61 crestal sinus elevation sites were recruited. The following changes in elevated sinus membrane area were recorded: vertical elevation height (VEH), buccopalatal elevation (BPE), and mesiodistal elevation (MDE). Cone beam computed tomography (CBCT) was used to measure the elevated height of the maxillary sinus floor at the initial examination, during surgery, and immediately after surgery. In addition, the VEH:BPE and VEH:MDE ratios at each site were calculated using CBCT to determine the probability of sinus membrane perforation. In average, 0.1 mL of bone graft material placed elevated VEH an average of 3.5 mm, while 0.2 mL and 0.3 mL of graft placed elevated VEH 5 mm and 6 mm, respectively. Furthermore, it was demonstrated that the VEH:BPE and VEH:MDE ratios play a determinant role on membrane integrity. As such, a ratio greater than 1.0 may jeopardize membrane integrity, while a ratio ≤ 0.8 might represent a lower risk of membrane perforation. An initial 0.1 mL of bone material filling can elevate sinus membrane vertically by 3.5 mm. To avoid sinus membrane perforation, a VEH:BPE or VEH:MDE ratio of ≤ 0.8 should be obtained.

Use of Buccal Fat Pad for Closure of Perforation and Graft Material in a Maxillary Sinus Elevation Procedure: A Preliminary Study.

Maxillary sinus membrane elevation is a common procedure intended to increase the volume of the maxillary sinus osseous floor prior to insertion of dental implants. The aim of this study was to evaluate bone formation under a perforated sinus membrane grafted with buccal fat pad (BFP). Six consecutive patients (10 sinus augmentations, 24 dental implants) underwent sinus floor elevation, using the lateral window approach. The compartment around the implants under the sinus mucosal lining in the sinus floor was filled with adipose tissues, which were retrieved as free graft from BFP. Clinical and radiologic follow-up was conducted through the healing period; in all cases, samples were taken for biopsy during the stage-two surgery. New bone consolidation in the maxillary sinus was radiologically and histologically observed within an average of 7.2 months after the sinus augmentation. According to the histomorphometric data, 62.8% ± 13.1% vital bone formation was observed. Out of the 24 implants placed, only 1 failed, indicating a 95% overall implant survival rate. Despite the limited size of this case series, BFP can be considered an autologous osteogenic graft material and/or biologic membrane capable of achieving high success rates in sinus elevation procedures.

EVALUATION OF COMBINATION OF BIPHASIC CALCIUM PHOSPHATE AND PLATELET-RICH FIBRIN AS GRAFTING MATERIAL FOR SINUS LIFT AUGMENTATION

INTRODUCTION: The performance of implant surgery in the posterior maxilla often poses achallenge due to insufficient available bone. Sinus floor elevation is developed to increase needed vertical height to overcome this problem. A lot of grafting materials has been used to augment subsinus area. The present study describes and reports a simple, safe and predictable bone graft mixture for the sinus lifting procedure. Recently, several authors have shown that simultaneous sinus lift and implantation using autologous platelet-rich fibrin combined with biphasic calcium phosphate as a grafting material is a reliable procedure promoting bone augmentation in the maxillary sinus. OBJECTIVE: This study is aiming to evaluate bone formation after maxillary sinus membrane elevation using lateral window technique and simultaneous implant placement with using biphasic calcium phosphate combined with pletelet rich fibrin as a grafting material. MATERIALS AND METHODS: The present study was conducted on ten patients with age ranged from 30-50 years seeking implantation of their lost posterior maxillary teeth, and has limited bone height below the floor of the maxillary sinus, secondary to sinus pneumatization. Patients were selected on the basis of history, clinical examination and radiographic examination using panoramic radiography and CBCT. CONCLUSION: PRF in addition to BCP may favor the formation of new bone after maxillary sinus augmentation. The effectiveness of PRF depends not only on its features but also the properties of coadministered grafting material. Key Words: Dental implant, Biphasic calcium phosphate, Platelet-rich fibrin, Sinus-lifts

On the Early Mechanisms of Bone Formation after Maxillary Sinus Membrane Elevation: An Experimental Histological and Immunohistochemical Study

Previous studies have shown predictable bone formation in the maxillary sinus after membrane elevation. However, how and where the bone is formed is not well understood. The aim of the study was to histologically and immunohistochemically study the early bone formation events in primates after membrane elevation in the maxillary sinus. Nine adult male tufted capuchin primates (Cebus apella) were included in the study. Eight animals were subjected to bilateral maxillary sinus membrane elevation using a lateral replaceable bone window technique. One oxidized dental implant was placed into the maxillary sinus cavity on both sides. In four animals, one sinus was left without any additional treatment, whereas the contralateral sinus was filled with autologous bone grafts from the tibia. In two animals, the implants were inserted under the elevated sinus membrane on both sides. In two animals, the sinus membrane was totally removed. The animals were euthanized after 10 or 45 days. One nonoperated animal representing pristine tissue conditions served as control. The maxillary sinuses with implants were retrieved and further processed for light microscopic ground sections or decalcified sections for immune-histochemical analyses. Bone formation started from the bottom of the sinus floor, sprouting into the granulation tissue along the implant surface under the elevated membrane irrespective of time and surgical technique. Bone formation was not seen in direct conjunction with the sinus membrane. A distinct expression of osteopontin was observed in the serous glands of the lamina propria close to the implant within all groups. Bone formation after sinus membrane elevation with or without additional bone grafts starts at the sinus floor and sprouts into the elevated space along the implant surface. The sinus membrane does not seem to present osteoinductive potential in sinus membrane elevation procedures in this study.