Bone reformation and implant integration following maxillary sinus membrane elevation: an experimental study in primates

Background: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell^TM, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone‐implant contact, bone area in threads, and bone area in rectangle). Results: The results showed no differences between membrane‐elevated and grafted sites regarding implant stability, bone‐implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone‐implant contact and bone area within threads were observed. Conclusions: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum‐alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures.     

压电超声骨刀在23例上颌窦提升术中的应用

目的:总结压电超声骨刀在上颌窦提升开窗手术中的临床应用,探讨其手术特点及术中注意的问题。方法:对符合上颌窦外提升术标准(种植区骨高度为5～8mm)的23例患者(24侧),进行了上颌窦外提升手术,术中应用压电超声骨刀进行上颌窦开窗手术,黏膜提升,填入人工骨粉,同期植入种植体。结果:24侧上颌窦提升手术,其中1侧由于术中操作不当,出现黏膜穿孔,终止手术;其余23侧均成功地进行了上颌窦提升,黏膜穿孔率仅为4.2%,并同期植入种植体48个,愈合期内(手术后10d拆线时)无感染及创口裂开等并发症。结论:应用压电超声骨刀进行上颌窦外提升手术,快捷、安全、可靠。     

Sinusfloor elevation and grafting with autogenous iliac crest bone.

Insufficient bone height in the posterior area of the maxilla, due to expansion of the maxillary sinus and atrophic reduction of the alveolar process of the maxilla, represents a contra-indication for insertion of dental implants. This anatomic problem can, in many cases, be solved by augmentation of the floor of the maxillary sinus. This surgical technique was introduced by Tatum. The so-called top hinge door method creates a new floor of the maxillary sinus at a more cranial level. Underneath this new floor the existing space is filled with a bone graft. Implantation in the alveolar process with increased bone height allows insertion of dental implants. This sinus grafting technique was used in the present study. In total, 62 sinusfloor elevations were performed with cancellous iliac bone grafts in 42 patients. In those 62 augmented sinuses, 161 ITI screw type implants were inserted. The follow-up was 1-6 years after implantation. In 2 cases infections occurred. One implant needed an extended integration time. No implants were lost. The ITI solid screw implant appears to be a suitable implant following sinusfloor elevation operations, due to its rough surface, its shape and the size of the thread. The sinusfloor elevation procedure with autogenous cancellous bone graft appears to be a valuable and reliable pre-implantological procedure, provided a proper pre-operative investigation and careful surgery are performed. This procedure allows dental implant placement with a high success rate.     

Sinus floor elevation and grafting with autogenous iliac crest bone

Insufficient bone height in the posterior area of the maxilla, due to expansion of the maxillary sinus and atrophic reduction of the alveolar process of the maxilla, represents a contraindication for insertion of dental implants. This anatomic problem can, in many cases, be solved by augmentation of the floor of the maxillary sinus. This surgical technique was introduced by Tatum. The so‐called top hinge door method creates a new floor of the maxillary sinus at a more cranial level. Underneath this new floor the existing space is filled with a bone graft. Implantation in the alveolar process with increased bone height allows insertion of dental implants. This sinus grafting technique was used in the present study. In total, 62 sinusfloor elevations were performed with cancellous iliac bone grafts in 42 patients. In those 62 augmented sinuses, 161 ITT screw type implants were inserted. The follow‐up was 1–6 years after implantation. In 2 cases infections occurred. One implant needed an extended integration time. No implants were lost. The ITI solid screw implant appears to be a suitable implant following sinusfloor elevation operations, due to its rough surface, its shape and the size of the thread. The sinusfloor elevation procedure with autogenous cancellous bone graft appears to be a valuable and reliable pre-implantological procedure, provided a proper pre‐operative investigation and careful surgery are performed. This procedure allows dental implant placement with a high success rate.     

Dental implant treatment with different techniques for sinus floor elevation--a case report

A 60-year-old man with missing maxillary molar teeth received dental implant therapy for reconstruction of occlusion. Sinus floor elevation with autogenous bone graft consisting of iliac bone block and particulate cancellous bone and marrow (PCBM) was performed in the bilateral maxillary sinuses for implant placement. On the right side, bone height in the molar region was less than 2mm. Therefore, a delayed protocol was applied, and 2 implants were placed 4 months after bone grafting. Bone graft resorption occurred during the healing period of 4 months. On the left side, 3 implants were placed simultaneously with sinus floor elevation, as bone height in the molar region was more than 4-5mm. The bone graft was carried out at the same time as implant placement. After implant placement, resorption of the bone graft stopped, and the superstructures were delivered on both sides. The tissues around the implants were clinically healthy at one year after examination. Sinus floor elevation with autogenous bone graft is an acceptable option for implant treatment in the maxillary molar region where there is adequate height of existing bone. In postoperative care, it is important to undertake adequate follow-up to ascertain occurrence of bone graft resorption.     

上颌窦内提升植骨及同期牙种植术中中空钻的应用

目的　介绍和评价在上颌窦内提升、植骨及同期牙种植术中使用中空钻的效果。方法对 2 4例牙槽骨高度不足的上颌后牙 ,用中空钻预备种植床、取骨 ,再行上颌窦底内提升 ,将所取的骨碾碎 ,植入上颌窦底 ,同期植入种植体 2 4例。术后 1周 ,1、3、6个月复查。结果　无种植体松动、脱落及上颌窦炎发生。 6个月后 ,X线片显示所植的骨改建成新骨 ,增加了牙槽骨高度 ,满足了种植要求 ;同时可见种植体与新骨形成紧密的骨性结合。种植体植入 6个月后行二期修复。结论　该法解决了上颌后牙区的牙槽骨高度不足 ,避免另处取骨。方法简单 ,值得临床推广。     

Long-term results with different bone substitutes used for sinus floor elevation

One of the surgical procedures preceding implantation is elevation of the base of the maxillary sinus. Numerous bone substituting materials (grafts) may be used for this purpose, including autogenous bone, heterografts, xenogenous bone, and synthetic materials alone or in combination or mixed with growth factors and bone morphogenetic protein (BMP) preparations. A study of the frequencies of the failures (graft material resorption or implant loss) after sinus elevations with various graft materials or their combinations was conducted. In the 5-year period from 1996 through 2001, a follow-up investigation of 810 maxillary sinus augmentations was performed, in which the sinus elevations involved the use of autogenous bone, a calcium carbonate-coated polymer, hydroxylapatite of algal origin, calcium carbonate gel produced from coral or beta-tricalcium phosphate alone, autogenous bone mixed with these bone substitutes, or a combination of beta-tricalcium phosphate and platelet-rich plasma. The incidences of graft resorption and implant loss after the augmentations with various bone substitutes were recorded. Total resorption (disappearance) of the bone substitute material was observed in 2.7% of the cases. An essential difference was not experienced between the various bone substitutes from this aspect, with the exception of the gel-state calcium carbonate, where 40% of the grafts were resorbed. In total, 5.46% of the implants were lost; the differences between the various materials were not significant.     

上颌窦区骨量不足3mm植骨后同期种植临床效果分析

目的:探讨在上颌窦区骨量不足3 mm的情况下,进行上颌窦底提升术并植骨同期将种植体植入的临床效果.方法:选择复旦大学附属中山医院和静安区牙病防治所2012年4月1日-2015年12月31日上颌后牙缺失患者56例,剩余牙槽骨高度均小于3 mm,术中行上颌窦底提升术并植骨,同期将种植体植入.术后3、6、12个月定期随访,分析及评估术后愈合效果及骨结合情况.结果:56例患者共植入72颗种植体,随访期间,种植体与周围骨组织结合良好,种植体稳定.术后6个月行种植修复,均能正常行使咀嚼功能,牙龈无形态、色泽异常,无并发症发生,手术成功率为100％.结论:对于上颌窦底骨量不足3 mm的患者,术中行上颌窦底提升术并植骨同期将种植体植入,也能取得良好的治疗效果.     

经牙槽嵴顶行上颌窦底提升同期植入种植体的疗效评价

目的:观察使用骨挤压器经牙槽嵴顶入路提升上颌窦底、同期植入种植体的临床效果。方法:对104例单侧或双侧上颌后牙缺失患者,经牙槽嵴顶入路行上颌窦底提升,同期植入种植体,共126颗。全部病例均行X线曲面断层片,其中30例在后期随访中行螺旋CT扫描及三维重建。结果:上颌窦剩余牙槽骨平均高度为9.16mm(5～11mm),用骨挤压器平均提升上颌窦底高度3.95mm(2～6mm),无1例上颌窦黏膜穿孔。随访16～82个月,成功率达100%,所有病例均无上颌窦并发症。CT扫描及三维重建显示,种植体顶端有一层完整骨质覆盖,种植体完全埋入骨质中。结论:应用骨挤压器,经牙槽嵴顶入路行上颌窦提升同期植入种植体,与上颌窦外提升术相比,手术创伤小、操作简便、并发症少,其近、远期效果均满意;螺旋CT扫描及三维重建可作为上颌窦提升种植体植入术后判断手术效果的有效手段。     

Maxillary sinus floor grafting with beta-tricalcium phosphate in humans: density and microarchitecture of the newly formed bone

OBJECTIVES: Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. MATERIALS AND METHODS: In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. RESULTS: Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4+/-10.9% and 34.7+/-11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than the control side. The TBPf value was lower on the control side than on the experimental side (-0.53+/-1.7 and -0.11+/-1.4 mm(-1), respectively), but this difference was not significant. CONCLUSIONS: Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.     

Maxillary bone grafting for insertion of endosseous implants: results after 12-124 months

Abstract: Insertion of endosseous implants in the atrophic maxilla is often complicated because of lack of supporting bone. Augmentation of the floor of the maxillary sinus with autogenous bone graft has been proven to be a reliable treatment modality, at least in the short term. The long‐term clinical and radiographic outcome with regard to the grafts, the implants and satisfaction of the patients with their implant‐supported overdenture was studied in 99 patients. The sinus floor was augmented with bone grafts derived from the iliac crest (83 subjects, 162 sinuses, 353 implants), the mandibular symphysis (14, 18, 37), or the maxillary tuberosity (2, 2, 2). Before implant installation, the width and height of the alveolar crest were increased in a first stage procedure in 74 patients, while in the other 25 patients augmentation and implant installation could be performed simultaneously (width and height of the alveolar crest >5 mm). Perforation of the sinus membrane occurred in 47 cases, which did not predispose to the development of sinusitis. Loss of bone particles and sequestration were observed in one (diabetic) patient only, in whom a dehiscence of the oral mucosa occurred. A second augmentation procedure was successful in this patient. Symptoms of transient sinusitis were observed in 3 patients. These symptoms were successfully treated with decongestants and antibiotics. 2 other patients developed a purulent sinusitis which resolved after a nasal antrostomy. In all cases, the bone volume was sufficient for implant insertion. 32 of 392 inserted Brånemark implants (8.2%) were lost during the follow‐up. After the healing period of the bone grafts, no sinus pathology was observed. The patients received implant‐supported overdentures (72 patients) or fixed bridges (27 patients). Overall, the patients were very satisfied with the prosthetic construction. We conclude that bone grafting of the floor of the maxillary sinus floor with autogenous bone for the insertion of implants is a reliable treatment modality with good long‐term results.     

几种植骨材料在外提升术骨高度改建的临床远期观察

目的：观察比较不同植骨材料在外提升植骨垂直骨高度的远期改建情况。方法：选择行外提升57例患者,随即分为三组,第一组植骨材料为100%Bio-Oss骨粉;第二组植骨材料为100%beta-TCP骨粉;第三组植骨材料为50%Bio-Oss混合50%beta-TCP骨粉。每个患者进行5次以上的全景片检查,其中三张进行定点定量检测。第一磨牙种植体的远中骨高度为L1,第一磨牙与第二磨牙种植体之间骨高度为L2,第二磨牙种植体远中5mm处的骨高度为L3。检测和比较垂直向骨高度的变化。结果：经60-84个月的临床追踪观察,每组L1,L2与L3垂直向骨高度改变无统计学意义的显著差异;100%Bio-Oss组与50%Bio-Oss＋50%beta-TCP组比较,骨高度无统计学差异,但100%Bio-Oss组与100%beta-TCP组比较,骨高度改变有统计学差异.结论：初始18个月,外提升骨垂直向高度改建较明显,18个月后骨高度变化较小,100%beta-TCP组与100%Bio-Oss组比较骨吸收明显。     

上颌窦底内提升同期植入种植体的临床效果观察

目的:观察单纯上颌窦内提升术同期牙种植修复的临床效果.方法:上颌后牙区牙槽骨严重吸收的36例患者,种植区剩余牙槽骨高度为(5.9±2.1)mm,行单纯上颌窦内提升同期牙种植术,共植入42枚种植体,其中瑞士Straumann种植体22枚、韩国奥齿泰SSⅡ种植体13枚、法国安多健种植体7枚.术后3～4个月,行上部结构修复,同时观察种植体的稳定性和种植体周围骨结合情况.随访期(12.2±3.6)个月.结果:36例患者上颌窦底提升高度(2.83±1.12)mnl,41枚种植体成功负载,种植体稳定,骨结合状况良好,无不良自觉症状.1枚种植体术后5周脱落,脱落2个月后重新种植,成功负载.结论:单纯上颌窦内提升同期牙种植术能有效治疗上颌窦底牙槽骨高度不足的上颌后牙缺失,手术创伤小,操作简便,并发症少,近期效果满意.     

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。     

Quantitative and qualitative comparison of the maxillary bone regeneration after beta-tricalcium phosphate and autogenous bone implantation

Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4 +/- 10.9% and 34.7 +/- 11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than on the control side. The TBPf value was lower on the control side than on the experimental side (-0.53 +/- 1.7 mm(-1) and -0.11 +/- 1.4 mm(-1), respectively); but this difference was not significant. Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.     

Recombinant human bone morphogenetic protein-7 in maxillary sinus floor elevation surgery in 3 patients compared to autogenous bone grafts. A clinical pilot study

BACKGROUND/AIMS: This pilot study was designed to determine the clinical bone formation ability of a human recombinant DNA bone morphogenetic protein-7, also referred to as Osteogenic Protein-1 [OP-1] combined with a collagen carrier, implanted in the maxillary sinus of 3 patients. The results were compared with a group of 3 patients treated with sinus floor elevation and autogenous bone grafts. METHODS: 6 consecutive patients, 4 female and 2 male, between 48 and 57 years of age were treated by means of sinus floor elevation for insufficient bone height in the posterior maxilla for implant surgery. 3 patients, 2 female and 1 male, were treated with OP-1 attached to a collagen device. In these patients, 4 maxillary sinus grafting procedures according to Tatum's method were carried out. 1 g of collagen carrier containing 2.5 mg rhOP-1 mixed with 3 ml of saline was placed between the bony floor and the elevated mucosal lining of the most caudal part of the maxillary sinus, in order to increase the vertical bone dimension to place dental implants of a sufficient length. The 3 other patients, also 2 female and 1 male, with a total of 5 sinus sites, were treated with sinus floor elevation and autogenous iliac crest bone grafts. After 6 months, during dental implant preparation, bone cores were taken for histology. Thus, clinical, radiological and histological results of the 2 groups of 3 patients were compared. RESULTS: 6 months after sinus grafting with OP-1, in 1 male, well-vascularized bone-like tissue of good quality was observed clinically. This could be confirmed by histology. In the second, female, patient no bone formation was observed at all. A cyst-like granular tissue mass, without purulent content, was removed. In the 3rd, female, patient, who received bilateral sinus grafts, some bone-like formation was seen, however it showed flexible tissue which led to the decision that at 6 months after the sinus grafting, the implant placement had to be postponed. In all 5 autogenous grafted sinuses a bone appearance similar to normal maxillary bone was observed clinically as well as histologically and dental implants could be placed six months after sinus floor elevation surgery. CONCLUSIONS: These findings indicate that the OP-1 device has the potential for initiating bone formation in the human maxillary sinus within 6 months after a sinus floor elevation operation. However, the various findings in these 3 patients indicate that the behaviour of the material is at this moment insufficiently predictable, in this indication area. Further investigation is indicated before OP-1 can be successfully used instead of the "gold standard" autogenous bone graft.     

Implant placement in fresh extraction sockets and simultaneous osteotome sinus floor elevation: a case series

The purpose of this study was to evaluate the clinical success of implants placed in fresh extraction sockets with simultaneous maxillary sinus floor elevation using the osteotome technique. Twelve patients were included. All the patients required the extraction of a maxillary premolar--close to the maxillary sinus--and were scheduled for immediate implant placement. One experimental implant was placed per patient, with an 18-month follow-up period. The graft materials used in both sinus augmentation and peri-implant bone defects were a mixture of collagen gel and corticocancellous porcine bone particles. All implants were allowed to heal for 6 months prior to prosthetic rehabilitation. One of the 12 experimental implants failed because of an abscess during early healing. No implants failed after definitive prosthetic rehabilitation. No significant bone loss was detected at the final follow-up visit. The mean bone height before sinus elevation and implant placement was 7.8 mm. Eighteen months after surgery, the mean bone height was 12 mm. When adequately performed, the surgical procedure described in the present study--immediate implant placement and simultaneous sinus floor elevation--appears to be unproblematic and predictable in terms of clinical success.     

Simultaneous dental implant placement and endoscope-guided internal sinus floor elevation: 2-year post-loading outcomes

Aims: To determine whether endoscope‐guided sinus elevation procedures can be consistently used to create sufficient bone support for stable implant placement and long‐term implant success. Material and methods: Sixty‐two implants were surgically placed into 30 patients (14 men and 16 women) following internal sinus elevation without the use of graft material. Panoramic radiographs were made pre‐, post‐operative and after 24 months in order to evaluate the peri‐implant bone and maxillary sinuses. Resonance frequency analysis (RFA) was used to evaluate implant stability immediately upon placement and just before prosthesis delivery. Results: The average pre‐operative height of the maxillary alveolar bone was 8.4±2.2 mm at the premolar and 7.3±3.1 mm at the molar regions. The average bone gain was 3.5±1.8 and 4.5±1.9 mm in the premolar and molar sites, respectively. Clinical parameters and the RFA (4 and 12 weeks post‐operative) outcomes show sufficient stability (ISQ=60) of the inserted implants. Three implants failed during the healing period of 12 weeks. The overall implant success rate was 94%. After loading, no further implant failure was observed. The overall success rate after beginning of implant loading was 100%. Conclusions: Sinus floor elevation is a well‐established procedure for augmentation of the atrophic maxillary posterior region. The minimally invasive internal sinus floor elevation procedure visually guided by an endoscope helped to prevent, diagnose and manage complications such as sinus membrane perforation. The clinical outcomes of this study show that endoscope‐controlled internal sinus floor elevation combined with implant placement results in low intra operative trauma, good implant stability upon placement, low incidence of post‐operative symptoms and high success rates after 24 months of loading.     

A clinical long-term radiographic evaluation of graft height changes after maxillary sinus floor augmentation with a 2:1 autogenous bone/xenograft mixture and simultaneous placement of dental implants

The aim of the present study was to assess long-term changes in sinus-graft height after maxillary sinus floor augmentation and simultaneous placement of implants. A total of 191 patients who underwent maxillary sinus floor augmentation were radiographically followed for up to about 10 years. A 2 : 1 mixture of autogenous bone and bovine xenograft (Bio-Oss) was used as the graft material. Sinus-graft height was measured using 294 panoramic images immediately after augmentation and up to 108 months subsequently. Changes in sinus-graft height were calculated with respect to implant length and original sinus height. Patients were divided into three groups based on the height of the grafted sinus floor relative to the implant apex: Group I, in which the grafted sinus floor was above the implant apex; Group II, in which the implant apex was level with the grafted sinus floor; and Group III, in which the grafted sinus floor was below the implant apex. After augmentation, the grafted sinus floor was consistently located above the implant apex. After 2-3 years, the grafted sinus floor was level with or slightly below the implant apex. This relationship was maintained over the long term. Sinus-graft height decreased significantly and approached original sinus height. The proportion of patients classified as belonging to Group III reached a maximum from year 3 onwards. The clinical survival rate of implants was 94.2%. All implant losses occurred within 3 years after augmentation. We conclude that progressive sinus pneumatization occurs after augmentation with a 2 : 1 autogenous bone/xenograft mixture, and long-term stability of sinus-graft height represents an important factor for implant success.     

三斜磷钙石糊剂封闭牙本质小管的体外研究

体外评价三斜磷钙石糊剂对牙本质小管的封闭作用,为牙本质敏感症的治疗提供新的手段。