Effect of sinus membrane perforation on dental implant integration: a retrospective study on 128 patients

A common complication of sinus augmentation is perforation of the sinus membrane during augmentation and/or implant placement. This retrospective study examines the effect of sinus membrane perforation with regard to graft survival and implant integration. A total of 175 sinuses were augmented with 115 of the membranes being reported intact at the time of surgery. A total of three infections occurred in patients who sustained perforated sinuses and one infection occurred in a patient who had an intact sinus. All four infections resolved after culture sensitivity and placement of the patient on an appropriate antibiotic for 10 days. Of 438 dental implants placed in the augmented sinuses, five implants failed, four of which were associated with perforated sinuses and and which was not associated with a perforated grafted sinus.     

Effect of Maxillary Sinus Membrane Perforation on Vital Bone Formation and Implant Survival: A Retrospective Study

Background: The maxillary sinus augmentation procedure (SAP) using the lateral window technique has been documented to be a highly predictable procedure. However, the most common intraoperative complication has been reported to be maxillary sinus membrane perforation (MSMP). The present study evaluates the percentage of vital bone and implant survival in sinuses that had perforations repaired during surgery versus a non‐perforated sinus group. Methods: Data were obtained retrospectively from an Institutional Review Board–approved anonymous database at New York University, Kriser Dental Center, Department of Periodontology and Implant Dentistry, New York, New York, from 23 patients who had undergone SAP with a total of 40 treated sinuses. Sinuses were grafted with mineralized cancellous bone allograft, anorganic bovine bone matrix, or biphasic calcium phospate. Perforation complications occurred in 15 sinuses with 25 non‐perforated sinuses. All perforations were repaired during surgery with absorbable collagen membrane barriers. Histologic cores were taken from all treated sinuses 26 to 32 weeks after surgery. The implant success rate of 79 placed implants was recorded. Results: The average percentage of vital bone was 26.3% ± 6.3% in the perforated (repaired) sinuses versus 19.1% ± 6.3% in the non‐perforated sinuses. The differences were statistically significant (SS). The implant success rate was 100% (35 of 35) compared to 95.5% (43 of 45) in the perforated/repaired vs. non‐perforated sinuses, respectively. There was no SS difference in implant failure rates. Conclusions: The augmented sinuses in this study that exhibited MSMPs that occurred during the SAP (which were treated during surgery) show SS greater vital bone percentages compared with the non‐perforated sinus group. There were no SS differences in implant survival in the perforated versus non‐perforated groups. In this study, sinus MSMPs, when properly repaired during surgery, do not appear to be an adverse complication in terms of vital bone production or implant survival.     

The clinical significance of sinus membrane perforation during augmentation of the maxillary sinus.

PURPOSE: Augmentation of the maxillary sinus floor is a well-documented technique and is generally accepted as a pure implantology procedure to facilitate placement of dental implants in the posterior atrophic maxilla. The objective of this report was to evaluate the significance of the sinus membrane perforations on the incidence, complications, and success rate of this procedure. PATIENTS AND METHODS: Patients who received sinus floor augmentation and simultaneous placement of dental implant were included in this study. Subgroup I consisted of patients who had their sinus membrane perforated and repaired during the procedure with resorbable membrane. Subgroup II consisted of patients whose Schneiderian membrane was not perforated during the procedure. The patients were followed between 1 to 4 years after augmentation. RESULTS: All perforations were classified as class II or III. The success rate of the implants in the perforation group was 94.4%, and that for the nonperforation group was 93.9%. The difference between the 2 study groups was statistically not significant. A significant statistical correlation was found between the residual ridge height and the membrane perforation (P < .01). CONCLUSIONS: Mainly due to technical difficulties, maxillary sinus membrane perforation occurs more frequently with a small height of residual alveolar bone. In this study, no statistical difference was observed in the success rate of the immediate implants placed with sinus bone grafting in patients whose membrane was perforated versus those patients in whom an intact membrane was maintained.     

Prevalence and management of Schneiderian membrane perforations during sinus-lift procedures

This clinical study was undertaken to evaluate the prevalence of surgical complications of the sinus graft procedure and to set a protocol to repair sinus membrane perforations intraoperatively using a variety of techniques and materials. From January 2000 to May 2005, 338 patients were studied, on whom 474 sinus floor augmentation procedures were performed, and a total of 1166 dental implants were simultaneously placed. A total of 104 perforations of the sinus membrane were observed (19 were bilateral). In group number 1, sinus membrane perforations of <5 mm were observed in 56 sinus augmentation procedures (53.85%), 44 were treated using a resorbable collagen membrane and 12 were sutured with a resorbable material. In group number 2, 28 sinus membranes had a perforation size between 5 and 10 mm (26.92%) and were treated using lamellar bone combined with a resorbable membrane. Group number 3 consisted of 20 sinus membrane perforations>10 mm (19.23%), 10 were covered with lamellar bone combined with a buccal fat pad flap, six were treated with a mandibular block graft and four perforations were treated with only a lamellar bone sheet. Two-hundred and seventy-eight implants were placed under repaired membrane perforations and 247 implants survived. Interestingly enough, all the 25 implants that failed to integrate were placed under perforated and reconstructed membranes during the sinus lift procedure. Based on the results of this study, the survival rates of implants placed under reconstructed membranes correlate inversely with the size of the perforations.     

Maxillary sinus augmentation using different grafting materials and osseointegrated dental implants in monkeys. Part IV Evaluation of hydroxyapatite‐coated implants.

The aim of this study was to evaluate clinically, histologically and histometrically the use of hydroxyapatite-coated dental implants in conjunction with maxillary sinus augmentation procedures. In 4 adult male Rhesus monkeys (Mucaca muluttu) the 3 maxillary molars on 1 side of the jaws were extracted and the remaining bone between the alveolar crest and the floor of the sinus was reduced to 3–4 mm. After 3 months, maxillary sinus augmentation procedures were performed in each monkey and the sinuses were grafted with a porous hydroxyapatite bone graft (Interpore-200®). At the same time, 2 hydroxyapatite-coated cylinder implants (IMZ®) were immediately placed into the augmented sinuses (i.e. simultaneous-implants-loaded group). Four months later, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed-implants-loaded group). After 4 months, the abutment connection was performed, and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that removal of the maxillary molars was performed 7 months after those in the opposite side, and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous-implants-unloaded group and delayed-implants-unloaded group) were obtained. Clinically, all loaded and unloaded implants were stable the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation, with integration of the porous hydroxyapatite graft particles and hydroxyapatite-coat of the dental implants to the new bone. Histometric analysis indicated that on the loaded side the implants placed simultaneously with the sinus lift procedure exhibited greater direct mineralized bone-to-implant contact than the delayed placed implants. In addition, the percentage of direct mineralized bone-to-implant contact was significantly greater in the residual bone in comparison to the augmented area in all groups. Loading of the implants exhibited a positive effect on the percentage of direct mineralized bone-to-implant contact in the augmented area. It could be concluded that hydroxyapatite-coated implants may be of benefit when used in conjunction with sinus augmentation procedures.     

Intrasinusal locking technique: a novel use of the ring block technique at sinus perforations for simultaneous implant placement

Ten patients who underwent sinus lift surgery with simultaneous implant placement using the intrasinusal locking technique were evaluated retrospectively. All patients were scheduled for sinus floor elevation procedures with simultaneous implant placement. Schneiderian membrane perforation occurred during the lifting procedure, and conventional methods failed to repair the perforation. Therefore, an autogenous bone ring was placed at the base of the maxillary sinus and was locked to the alveolar crest with a dental implant. Marginal resorption around the dental implants was measured on panoramic radiographs. Prosthetic rehabilitation was performed at 6 months postoperative. The overall survival rate of the implants over a mean follow-up of 24.3 months was 90%. One case failed due to resorption of the alveolar crest around the implant as a result of infection; the implant and the adjacent ring were removed at 1 month postoperative. At the time of writing, the nine implants placed using the documented technique continue to function well, without any signs of peri-implant disease. The proposed approach allows for simultaneous dental implant placement in the extremely atrophic maxilla, even if there is extensive perforation of the Schneiderian membrane.     

Survival Rate for Implants Placed in the Posterior Maxilla With and Without Sinus Augmentation: A Comparative Cohort Study

Background: The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla. Methods: This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two‐stage technique. Patients were scheduled for follow‐up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤6 years. Results: One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005). Conclusions: These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.     

Effects of sinus membrane perforations on the success of dental implants placed in the augmented sinus

BACKGROUND: Maxillary sinus lifting procedure enables clinicians to place implant-supported prostheses even in cases with very limited vertical bone height of the maxillary sinus. The aim of this study was to evaluate the implant success with regard to effects of the sinus membrane perforations that occurred during sinus lifting surgery. METHODS: The study group consisted of 91 patients (29 females and 54 males) with edentulous posterior maxilla. Implant placement combined with sinus lifting surgery was performed, and 259 implants were inserted. Sinus membrane perforations were detected in 12 sinus sites. After proper treatment of perforations, 26 implants were placed into perforated sinus areas. Baseline panaromic radiographs were taken before the beginning of prosthetic treatment. Panaromic radiographs taken at the last recall were used for evaluation and compared to the baseline panaromic radiographs using image analysis software to reveal the peri-implant resorption rate for the implants placed in perforated and non-perforated sinus area. The modified sulcus bleeding index and plaque index were used for the assessment of soft tissue conditions. RESULTS: Eleven implants were lost during the follow-up period, resulting in an overall survival rate of 95.9%. Two failures occurred in the group with sinus perforations. There was no statistically significant difference regarding peri-implant bone resorption (P = 0.778) and soft tissue conditions for implants placed into perforated-augmented sinus areas and augmented sinus areas. CONCLUSION: Within the limits of this study, perforation of the sinus membrane did not compromise the osseointegration process or the success of dental implants placed in the augmented maxillary sinus.     

A Clinical and Histological Case Series Study on Calcium Sulfate for Maxillary Sinus Floor Augmentation and Delayed Placement of Dental Implants

Background: Maxillary sinus floor augmentation is a procedure that is indicated in cases when the volume of the posterior maxillary bone is inadequate. The goal of this treatment is to obtain sufficient amount of bone tissue in order to gain osseointegration of endosseous implants. Purpose: The purpose of this study was to conduct a clinical and histological analysis of calcium sulfate (CaS) as bone graft substitute in sinus floor augmentation. Material and Methods: Ten patients with edentulous maxillas were included in this study. They had moderate to severe atrophy of the posterior maxilla. Surgiplaster (Classimplant®, Rome, Italy) was used as graft material in the maxillary sinus and was covered by BioGide® (Geistlish Pharmaceutical, Wolhusen, Switzerland). After 4 months of graft healing, 40 dental implants were placed and a biopsy for histomorphometry was taken at these occasions. The specimens were viewed by light microscope, and the extent of bone regeneration and remaining graft material was evaluated. Radiographs were taken at the time of sinus augmentation and after 4 months of graft healing. Results: At the time of abutment surgery, one implant was considered as a failure and was consequently removed, giving a survival rate of 97.5% after 1 year of loading. Radiographs showed a mean of 26.5% shrinkage of the augmented area. A significant resorption of CaS was noted with a mean value of 8.8% of remaining graft material after 4 months of healing. The biopsies also revealed new bone formation with a mean value of 21.2% of the total biopsy area. Histology showed signs of an acellular substitution of CaS with bone‐like tissue. Conclusion: The results of this study show that new bone regeneration occurs in the maxillary sinus after augmentation with CaS. This enabled successful placement, integration, and loading of dental implants in the posterior maxilla, as only 1 of 40 implants was lost during 1 year of follow‐up.     

Evaluation of the Effectiveness of a Water Lift System in the Sinus Membrane‐Lifting Operation as a Sinus Surgical Instrument

Purpose: The effectiveness of a Water Lift System in the sinus membrane‐lifting operation was examined. This investigation focused on the capability of this equipment to reduce the risk of Schneiderian membrane perforation. Materials and Methods: A preliminary clinical study on the use of the Water Lift System in sinus membrane elevation to place implants through the sinus floor was conducted. A total of 70 sinus membrane‐lifting operations were performed on patients with various bone heights ranging from 1.2 to 9.9 mm (most commonly in the range of 4–6 mm) through the lateral approach (four cases) or the crestal approach (66 cases). Results: In all of the cases performed using the lateral approach, sinus membrane perforation did not occur. In the 66 cases performed using the crestal approach, Schneiderian membrane tearing occurred in two cases. The membrane tearing occurred during elevation of the Schneiderian membrane but not when a hole was drilled to access the Schneiderian membrane. One case of membrane tearing resulted from previous inflammation in the maxillary sinus, and the other case of membrane tearing was caused by application of excessive hydraulic pressure. In addition, similar outcomes were obtained and no microbial infections were observed in a total of 68 successful cases. Conclusions: In this study, the Water Lift System was confirmed to effectively reduce the risk of Schneiderian membrane perforation during the sinus membrane‐lifting operation. We conclude that the Water Lift System deserves to be considered as a sinus surgical instrument, which ensures safety in the sinus membrane‐lifting operation.     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys

The aim of this study was to evaluate clinically, histologically and histometrically the use of anorganic bovine bone matrix (i.e. Bio-oss®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Mucaca mulattu) the 1st 2nd and 3rd maxillary molars on one side of the jaws were extracted. The remaining bone between the alveolar crest and the bottom of the sinus was then reduced to 3–4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey and the sinuses were grafted with the bovine bone matrix. At that time, 2 IMZ pure titanium plasma coated implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into these previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants-unloaded group and delayed implants-unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited significant bone formation with integration of the bovine bone matrix particles to the new bone. Direct mineralized bone-to-implant contact was greater for the delayed implant placement groups than for the implants installed simultaneously with the sinus augmentation. Furthermore, the percentage of direct mineralized bone-to-implant contact was greater in the residual bone than in the augmented area. It was concluded that the anorganic bovine bone matrix facilitated bone formation and implant osseointegration in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure seemed to be preferable.     

Long‐term Schneiderian membrane thickness changes following zygomatic implant placement: A retrospective radiographic analysis using cone beam computed tomography

Objectives

The purpose of this retrospective study was to evaluate the long‐term changes in the thickness of Schneiderian membranes after zygomatic implant placement using cone beam computed tomography (CBCT).

Material and methods

Twenty‐five consecutive patients were included in this study. All the patients underwent bilateral zygomatic implant placement. Schneiderian membrane thickness (SMT) in 49 maxillary sinuses (one sinus was not included because of early loss of the zygomatic implants) was measured using CBCT before and at least 1 year after zygomatic implant placement. Ostium patency of each sinus was also evaluated and recorded.

Results

In total, 84 zygomatic implants and 30 regular implants were placed in included patients. Two unilateral maxillary zygomatic implants in one patient were removed 2 months after implant placement. The SMT increased from 1.03 mm (inter‐quartile range: 1.57 mm) to 1.33 mm (inter‐quartile range: 1.98 mm) after a median follow‐up time of 23.00 months (inter‐quartile range: 14 months), and the difference was statistically significant. Before zygomatic implant insertion, 24.5% (12/49) of sinuses had SMT greater than 2 mm, whereas this value was 28.6% (14/49) after zygomatic implant placement. The percentage of sinuses observed with ostium patency also increased from 2.0% (1/49) to 12.2% (6/49).

Conclusions

Chronic Schneiderian membrane thickening could result from zygomatic implant insertion. Intensive postoperative care and clinical and radiographic monitoring are recommended after zygomatic implant placement.     

Maxillary sinus augmentation using different grafting materials and osseointegrated dental implants in monkeys. Part II. Evaluation of porous hydroxyapatite as a grafting material.

The aim of this study was to evaluate clinically, histologically and histometrically the use of porous hydroxyapatite (i.e. Interpore-200®) as a bone grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Macaca mulatto) the lst, 2nd and 3rd maxillary molars on one side of the jaws were extracted and the remaining bone between the alveolar crest and the bottom of the sinus was reduced to 3–4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey, and the sinuses grafted with the porous hydroxyapatite. Two IMZ@ titanium plasma-sprayed cylinder implants were then immediately placed into the augmented sinus (i.e. simultaneous implants-loaded group). After 4 months. 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice). The contralateral side of each monkey received the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants-unloaded group and delayed implants-unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologic analysis demonstrated a significant amount of new bone formation in the augmented sinuses. Porous hydroxyapatite graft particles appeared to be integrated to the new bone. The percentage of direct mineralized bone-to-implant contact in the augmented area was greater on the delayed-placed implants than on the simultaneously-placed implants. Also, the percentage of direct mineralized bone-to-implant contact was greater in the residual bone than in the augmented area. It was concluded that this porous hydroxyapatite bone graft enhanced bone formation and bone-to-implant contact in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure appears to result in a higher percentage of direct mineralized bone-to-implant contact.     

Maxillary sinus augmentation using sinus membrane elevation and peripheral venous blood for implant-supported rehabilitation of the atrophic posterior maxilla: case series

Background Dental implants need appropriate bone volume for adequate stability in the rehabilitation after tooth loss. In the severely atrophic posterior maxilla, the clinical success of implant treatment sometimes requires a vertical ridge augmentation in the maxillary sinus floor. Purpose The purpose of this investigation was to evaluate a maxillary sinus floor augmentation technique using a replaceable bone window, elevation of the membrane, placement of implants, and injection of the patient’s own venous blood to fill the voids. Materials and Methods Six patients with need of maxillary sinus floor augmentation participated in the study. After preparation of a replaceable bone window in the lateral aspect of the sinus and careful elevation of the Schneiderian membrane, a total of 14 Brånemark implants (TiUnite, MK III, Nobel Biocare AB, Göteborg, Sweden) were installed in the residual bone penetrating into the sinus cavity. The sinus cavity was then filled with peripheral venous blood and the bone window replaced and stabilized with a medical tissue glue (Aron Alpha A, Sankyo, Inc., Tokyo, Japan) to prevent blood leakage from the created compartment in the maxillary sinus. Results After a healing period of a minimum of 6 months, new bone was successfully generated in all 14 implant sites as judged from radiographs. One of the 14 implants failed, corresponding to a survival rate of 92.9% after a follow‐up period ranging 12 to 34 months. Conclusions The present case series demonstrate that the creation of a secluded space in the maxillary sinus and filling with venous blood results in bone formation at simultaneously installed dental implants over a 6‐month period.     

开窗植骨与闭合冲压上颌窦底提升同期种植的临床研究

目的:研究比较上后牙缺失牙槽嵴高度不足患者,根据上颌窦底牙槽嵴骨高度不同,选用开窗植骨或闭合冲压提升上颌窦底,同期种植牙的治疗效果。方法:43例(55侧)上后牙缺失患者,其中34例(40侧)窦底牙槽嵴骨高6~10 mm者行闭合冲压上颌窦底提升术,其余9例(15侧)骨高2~5 mm者行开窗植骨上颌窦底提升手术,均同期完成一期种植体植入手术。结果:所有患者术后未出现上颌窦炎症,9例行开窗植骨上颌窦底提升手术的患者,无窦膜穿孔,平均提升窦底高度5.8 mm,26颗种植体平均负载30个月,种植体稳定,骨结合状况良好。34例行闭合冲压上颌窦底提升术的患者,平均提升窦底高度4.3 mm,手术操作中有3颗发生可察觉窦膜破孔,发生率为4.1%(3/73),在73颗种植体中,有2颗种植体失败,71颗种植体平均负载23个月,种植体稳定,未见明显骨吸收,成功率97.3%(71/73)。结论:闭合冲压上颌窦底提升术是一种微创、简单、可靠用于上颌后牙上颌窦底牙槽嵴骨高度不足的种植临床技术,临床上应根据上颌窦底牙槽嵴骨高度不同,选用开窗植骨或闭合冲压提升上颌窦底。     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Evaluation of autogenous bone combined with porous hydroxyapatite.

The aim of this study was to evaluate clinically, histologically, and histometrically the use of autogenous bone combined with porous hydroxyapatite (Interpore 200®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (Macaca mulatta) the 1st, 2nd and 3rd maxillary molars on one side of the jaws were extracted. After a healing period of 3 months. maxillary sinus augmentation procedures were performed in each monkey, and the sinuses were grafted with autogenous bone from the monkeys' tibia mixed in a 3:1 ratio with porous hydroxyapatite. At the same time. 2 pure titanium plasma-sprayed IMZB cylinder implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received similar treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants unloaded group and delayed implants unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation. The porous hydroxyapatite granules appeared integrated with the newly formed bone. Histometric analyses revealed that delayed implant placement resulted in a greater amount of direct mineralized bone-to-implant contact in the augmented area than the simultaneous implant placement. Furthermore, the percentage of direct mineralized bone-to-implant contact was far more significant in the residual bone than in the augmented area. It was concluded that the autogenous bone/porous hydroxyapatite graft combination enhanced bone formation and mineralized bone-to-implant contact in the augmented sinuses and that the delayed implant placement may be favorable for sinus augmentation procedures.     

Cholesterol Granuloma of the Maxillary Sinus Encountered during Floor Augmentation Procedure: A Case Report

Background: Cholesterol granuloma (CG) is a foreign‐body reaction to the deposition of cholesterol crystals. Its occurrence in the paranasal sinuses is very rare. Purpose: This report describes a new case of maxillary sinus CG discovered incidentally during sinus‐floor augmentation for dental implant placement in a 60‐year‐old female patient. Materials and Methods: The preoperative clinical and radiological examinations revealed a normal maxillary antrum with no evidence of sinus pathology. After lateral osteotomy, a dark‐green, viscous soft tissue mass appeared through the thin mucous membrane inside the sinus. Enucleation and curettage of the sinus contents including the sinus membrane were performed for histopathologic analysis. The augmentation and implant placement procedures were postponed. Results: Histopathologic analysis showed several fragments of granulation tissue containing diffuse cholesterol clefts surrounded by mixed chronic inflammatory cell infiltrate including plasma cells and lymphocytes. These features were compatible with the diagnosis of CG. The patient was followed up for 3 months after the first procedure, and a second attempt of sinus augmentation and dental implant insertion was then carried out. The inserted dental implants were followed up for 6 months without any complications. Conclusions: CG of maxillary sinus can be an incidental finding. For this reason, the final diagnosis can only be achieved after examination of the material under the microscope.     

Five-year outcome of bone remodelling around implants in the maxillary sinus: assessment of differences between implants placed in autogenous inlay bone blocks and in ungrafted maxilla

The placement of implants in the posterior maxillary area is considered a reliable procedure, offering recognized rehabilitative advantages. The aim of this study was to evaluate the performance of dental implants placed in the sinus floor augmented with a block autograft by comparing the outcomes over 5 years with those of dental implants positioned in non-augmented bone. This retrospective cohort study included 16 patients who had undergone prosthetic rehabilitation supported by dental implants between 2000 and 2006. One implant per patient was included and assigned to one of two predictor groups: grafted versus ungrafted maxillary sinus. Changes in marginal bone level (MBL) and apical bone level (ABL) over time, at 1, 3, and 5 years, were the primary outcome variables. Appropriate pair-wise comparison tests were performed. No significant differences were seen with regard to ABLs and among times between the grafted group (nine implants) and the ungrafted group (seven implants). Significant marginal bone resorption was found over time, primarily at the buccal aspect, in both study groups. The bone surrounding the apex of dental implants appeared stable after sinus augmentation in the grafted area. The behaviour of the two groups with regard to loss of MBLs over time was very similar.     

Internal sinus manipulation (ISM) procedure: a technical report

Background The sinus augmentation procedure has facilitated dental implant treatment in the posterior maxilla where there is insufficient bone for implant placement. A modified Caldwell‐Luc, lateral window technique can be applied in most cases needing sinus augmentation in order to create a larger bone volume. However, treatment morbidity can be a concern, especially in the form of postoperative swelling due to surgical trauma. Vertical augmentation using osteotomes has also been selected as a choice of treatment due to less invasive surgery and less postoperative trauma. Although the osteotome technique enables the surgeon to raise the sinus membrane internally through an implant osteotomy site, the quantity and predictability of bone augmentation can be limiting due to the elasticity of the Schneiderian sinus membrane, difficulty of the membrane to separate from the floor as well as the inability to have direct tactile access to “peel” the membrane off of the floor. Purpose The objective of this report is to present a new, minimally invasive sinus augmentation technique, called the Internal Sinus Manipulation (ISM) procedure, which has been developed to facilitate sinus floor augmentation while reducing treatment morbidity and yet have direct tactile access to raise the membrane off of the sinus floor. Surgical Technique Access to the Schneiderian sinus membrane is achieved without perforation of the membrane through a conventional osteotomy drilling procedure alone or combined with osteotome technique, followed by reflection of the membrane utilizing special ISM instrumentation and bone graft procedure laterally and vertically through the osteotomy site. A planned implant is then placed. Conclusion The Internal Sinus Manipulation procedure can be used as an alternative treatment modality for sinus augmentation as compared to the external lateral window technique while reducing postoperative morbidity for the patients who need implant treatment in posterior maxillary areas.     

Freeze-dried bone for maxillary sinus augmentation in sheep. Part II: biomechanical findings

This study examines the biomechanical loading capacity of dental implants placed in the posterior maxilla in conjunction with subantral augmentation with either homogeneous demineralized freeze-dried bone from sheep (s-DFDB) or heterogeneous demineralized freeze-dried human bone (h-DFDB) as grafting material in sheep. In 36 adult female mountain sheep, the Schneiderian membrane was elevated extraorally in both maxillary sinuses, and two titanium plasma-flame-sprayed cylindrical implants were inserted in each lateral antral wall. Three groups of 18 maxillary sinuses each were augmented with s-DFDB, h-DFDB and autogenous bone from the illiac crest, respectively. In the remaining 18 sinuses, the subantral hollow space was left empty. Pull-out tests were carried out after intervals of 12, 16 and 26 weeks. The mean pull-out force needed, irrespective of time, was 259.3 N in the empty control group, 356.7 N in the group augmented with autogenous bone, 278.1 N in the test group augmented with h-DFDB and 365.2 N in the group augmented with s-DFDB, revealing no significant difference between the individual groups (P > 0.05). The implants of the group augmented with autogenous bone showed an increase in the mean pull-out force from 223.8 N after 12 weeks to 523.7 N after 26 weeks. The nonaugmented control group yielded values of 248 N after 12 weeks, which rose to 269.8 N at the last test, while the values of the h-DFDB group increased from 275.4 N to 325.4 N. The highest initial pull-out values were obtained in the s-DFDB group. They amounted to 310.5 N after 12 weeks and rose to 481.4 N after 26 weeks. Time thus proved to have a significant influence on the pull-out forces (P = 0.014) with a statistically proven linear trend (P = 0.007). The findings of this experimental study indicate that the use of homogeneous DFDB in one-stage sinus lift procedures results in a mechanical loading capacity of implants comparable to that achieved by autogenous cancellous bone from the iliac crest. In contrast, the use of heterogenous-DFDB resulted in only slightly higher pull-out forces than those observed in the nonaugmented control group after 26 weeks.