7-year follow-up of 93 immediately loaded titanium dental implants

Recently, several experimental and clinical investigations found that immediately loaded implants obtained satisfactory levels of osseointegration with high success percentages. Only a few long-term studies of immediately loaded implants have been reported in the literature. The aim of this study was a 7-year clinical and radiographic follow-up of 93 immediately loaded dental implants in human patients. Eleven patients were consecutively enrolled in this study. A total of 7 full and 9 partial edentulous arches were rehabilitated. Patients presented a completely edentulous mandible (n=6), a completely edentulous maxilla (n=1), mandibular posterior edentulous areas (n=5), or a posterior maxillary edentulous area (n=1). Patients were rehabilitated with a bar and an overdenture (n=4), a provisional prosthesis of 3 to 12 elements (n=11), or a metal-ceramic bridge of 10 elements (n=1). A total of 93 implants were inserted and loaded within a 24-hour time frame. Six implants failed in the first year after loading. No more failures were observed in the following 6 years, and all the other implants were well integrated from a clinical and radiographic point of view. The cumulative success rate at 7 years was 93.5%, and the prostheses survival rate was 98.5%. The mean marginal bone loss was 0.6 mm after the first year and 1.1 mm at the 7-year evaluation. Primary stability is one of the most important parameters in immediately loaded implants because it avoids micromotion at the bone-implant interface. Four of the 6 failures in our patients occurred in partially edentulous patients; an excessive load applied to these small bridges could be the reason for the failure. Also, the bone quality is important, for 3 of our failed implants had been inserted in D3 bone. Our clinical and radiographic results have shown that these immediately loaded implants have remained osseointegrated for a long period. Our results point to the possibility of using the immediate loading technique in selected and well-informed cases.     

Early tissue reaction at the interface of immediately loaded dental implants

PURPOSE: The treatment of patients with early or immediately loaded dental implants has renewed interest in the behavior of osteoblasts at the implant surface under load. A newly designed dental implant indicated for immediate loading was tested in vivo for early stages of osteoblast behavior at the implant surface. MATERIALS AND METHODS: Thirty-two implants were placed in the mandibles of 8 minipigs. Half of the implants (n = 16) were immediately loaded under occlusal contacts, and implants placed in non-occlusal relations served as a control. RESULTS: All implants, except 1 that showed signs of tissue infection, healed uneventfully and were stable throughout the experimental period. Ultrastructural analysis of mandibular specimens revealed an intimate attachment of osteoblasts to the material surface beginning as early as day 1. Application of either occlusal or non-occlusal load did not alter the phenotypic morphology of the attached osteoblasts. Transmission electron microscopy and x-ray diffraction analysis demonstrated a direct contact of bone-like minerals over the whole implant surface with no signs of crestal hard tissue alteration. Electron diffraction analysis showed a slight release of titanium from the implant side. DISCUSSION: These results indicate that immediate loading of specially designed dental implants can be performed without disruption of the titanium/bone interface or disturbance of osteoblast physiology in the early loading phase. CONCLUSION: Immediate loading protocols can be performed without disturbance of normal bone biology.     

Systematic review of survival rates for implants placed in the grafted maxillary sinus

Based on a systematic review of the literature from 1986 to 2002, this study sought to determine the survival rate of root-form dental implants placed in the grafted maxillary sinus. Secondary goals were to determine the effects of graft material, implant surface characteristics, and simultaneous versus delayed placement on survival rate. A search of the main electronic databases was performed in addition to a hand search of the most relevant journals. All relevant articles were screened according to specific inclusion criteria. Selected papers were reviewed for data extraction. The search yielded 252 articles applicable to sinus grafts associated with implant treatment. Of these, 39 met the inclusion criteria for qualitative data analysis. Only 3 of the articles were randomized controlled trials. The overall implant survival rate for the 39 included studies was 91.49%. The database included 6,913 implants placed in 2,046 subjects with loaded follow-up time ranging from 12 to 75 months. Implant survival was 87.70% with grafts of 100% autogenous bone, 94.88% when combining autogenous bone with various bone substitutes, and 95.98% with bone grafts consisting of bone substitutes alone. The survival rate for implants having smooth and rough surfaces was 85.64% and 95.98%, respectively. Simultaneous and delayed procedures displayed similar survival rates of 92.17% and 92.93%, respectively. When implants are placed in grafted maxillary sinuses, the performance of rough implants is superior to that of smooth implants. Bone-substitute materials are as effective as autogenous bone when used alone or in combination with autogenous bone. Studies using a split-mouth design with one variable are needed to further validate the findings.     

Preliminary report of immediately loaded Altiva Natural Tooth Replacement dental implants

Background : Osseointegration may be described as a direct contact between living bone and an alloplastic implant. It is thought that a period of undisturbed healing is required to ensure osseointegration. The length of the healing period is dependent on a number of factors, such as implant material, surface configuration, site preparation technique, bone quality, healing capacity of the osteotomy, and implant design. Elimination of the healing period offers distinct advantages in terms of cost of therapy and convenience to patients. Recently, a new one-piece implant design was proposed that provides improved stability of the implant to allow immediate support of an interim prosthesis.
Purpose : This article presents the initial clinical experiences when the Altiva Natural Tooth Replacement one-piece implant was used in a human clinical trial.
Materials and Methods : This was a prospective multicenter study of the placement and immediate loading of the one-piece implant. A total of 142 implants were placed in the jaws of 93 patients. Implants were placed consecutively and were followed at specified intervals in three private clinical practices. Clinical performance was recorded relative to implant survival and prosthesis support.
Results : The implant survival rate was 93.7%, with similar responses in the maxilla (95.0%) and the mandible (92.7%). When implant failure occurred, it was observed as mobility without infection within 3 to 5 weeks of implant insertion.
Conclusions : On the basis of this trial, there is promising evidence that this implant design can succeed at rates similar to other designs that require conventional healing times.     

Wound healing in immediately loaded implants

The orthopedic field has accumulated ample evidence that bone formation is related to functional loading and in general to physical activity. However, despite evidence that immediately loaded implants can be predictably successful, many clinicians still use the classical (delayed loading) treatment protocol. This paper examines the effects of loading on dental implants and discusses the advantages of immediate loading. The role of loading on augmented alveolar ridges is also addressed and provides evidence that early bone resorption may be controlled when bone is functionally loaded. Similar data are emerging for advanced augmentation techniques in order to control crestal bone loss.     

即刻负重带内孔种植体的长期效果

目的：对应用即刻负重Straumann种植体支持杆固位覆盖义齿的患者，进行长期效果回顾性评估。材料和方法：所有病例均为自1981～1991年期间在巴塞尔大学口腔外科、口腔放射科和口腔内科学院进行外科手术和修复治疗的患者。每例患者均于手术当时安装连接杆带入义齿即刻负重。对能随访到的患者进行临床复诊检查，并对结果进行统计学分析。结果：44例患者植入176颗带内孔Straumann种植体的患者中（每个患者4颗），其中随访到23例患者共89颗种植体。种植体的平均观察时间为122年（8～18年）。3例种植体脱落。5例种植体不符合预定的成功标准。根据Cutler和Ederer的定义．成功概率为83．3％。结论：结果表明，即刻负重带内孔Straumann种植体不一定需骨结合所要求的4个月治疗期。     

Changes in crestal bone levels for immediately loaded implants

PURPOSE: The authors' objective was to measure crestal bone level change in subjects with immediately loaded implants and to identify risk factors associated with changes in bone level. MATERIALS AND METHODS: A retrospective cohort study design was used. The sample comprised subjects who had had endosseous implants placed and immediately loaded between July 2001 and July 2003. Demographic, health status-related, anatomic, implant-specific, prosthetic, and surgical variables were examined. The primary outcome variable was change in crestal bone level over time. Appropriate uni-, bi-, and multivariate statistics were computed. RESULTS: The sample comprised 174 subjects who received 347 immediately loaded implants. The mean duration of radiographic follow-up was 6.9 +/- 4.0 months, respectively. Mean changes in radiographic bone level were -0.5 mm and -0.6 mm on the mesial and distal surfaces, respectively, after a mean of 6.9 months of radiographic follow-up. Using least squares methods, it was estimated that radiographic bone levels would be -1.0 mm and -0.8 mm on the mesial and distal surfaces, respectively, at 12 months. The multivariate model revealed that radiolucency at or adjacent to implant site was associated with an increased risk of crestal bone loss (odds ratio, 1.88; 95% CI, 1.00 to 3.60). Twelve months after placement, 92.5% of implants had had < or = 1.5 mm of crestal bone loss. DISCUSSION: The results of this study were comparable to the results of other studies comparing immediate loading to delayed loading. Further research to estimate long-term changes in crestal bone loss and to identify risk factors for bone loss with immediate loading is recommended. CONCLUSION: This study suggests that crestal bone level changes with immediately loaded implants were within the recommended range for 92.5% of the evaluated implants. The mandible showed a higher risk for crestal bone loss compared to the maxilla.     

种植体即刻负重的临床修复设计

目前,口腔种植被认为是牙列缺损及牙列缺失患者最佳的修复选择~([1]).经典的方法要求,种植体植入后必须经过3～6个月的无负荷愈合期,再行咬合功能修复,才能形成骨结合(osseointegration),获得具有较高强度的应力传导结构~([2]).     

Prognosis of immediately loaded implants and their restorations: a systematic literature review

Immediate loading of oral implants has become popular because of the increasing demands of a shortened treatment time. This literature review evaluates the prognosis of immediately loaded implants and their restorations with immediate or delayed implant placement. Special attention was given to the impact of type of jaw, bone quality, implant length, time of implant placement and type of restoration. An electronic (PubMed) and a manual search in relevant journals were conducted until February 2012. Only publications in English, in peer-reviewed journals, were considered. Nine studies met the inclusion criteria: five studies dealt with fixed restorations, two studies with removable rehabilitation of edentulous jaws and two studies dealt with partially edentulous patients. Implant survival rates ranged from 95·8% to 100%, implant success rates in the treatment for the mandible from 79% to 100% and restoration survival rates for both jaws from 96·4% to 100%. Within the limits of this review, appropriate patient selection, primary implant stability, splinting of implants and the expertise of surgeons seem to be important for the prognosis of immediately loaded implants and their restorations. Good bone quality and use of long implants appear to play a role. However, careful interpretation is required because conclusions are based on articles with low level of evidence. While immediate loading of oral implants in the mandible shows encouraging and predictable results, further multicenter randomised controlled clinical trials with sufficient statistical power are needed to examine (i) the outcome of immediately loaded implants in the maxilla and (ii) the outcome of immediate loading of immediately placed implants.     

Long-term results of immediately loaded interforaminal implants.

OBJECTIVE: To collect, retrospectively, long-term results from patients who received immediately loaded Straumann implants with bar-retained overdentures. METHOD AND MATERIALS: The surgical and prosthetic treatment took place between 1981 and 1991 at the Department of Oral Surgery, Oral Radiology, and Oral Medicine, University of Basel. In each case on the day of the operation, the patients were fitted with a bar that was immediately loaded with a hybrid prosthesis. Patients who were available at the time of this study were clinically reexamined and statistically assessed. RESULTS: Among the 44 patients who received 176 interforaminal Straumann implants (4 implants per patient), follow-up was possible in 23 patients, who had received a total of 89 implants. The mean observation time for the implants was 12.2 years (8 to 18 years). Three implants were lost. Five implants did not meet the predetermined success criteria. Using the definition by Cutler and Ederer, the probability of success was 83.3%. CONCLUSIONS: The results show that the requisite 4-month healing time for immediately loaded interforaminal Straumann implants with bars does not have to be observed.     

Survival of immediately loaded dental implants in deficient alveolar bone sites augmented with beta-tricalcium phosphate

PURPOSE: Dental implant placement in atrophic alveolar ridges often necessitates grafting procedures, followed by immediate or delayed implant placement. This study assessed the survival of immediately loaded dental implants placed in deficient alveolar bone sites at bone grafting. MATERIALS: From 1999 to May 2002, 1 operator (A.P.) inserted 1065 implants (607 in mandibles, 458 in maxillae) into 338 partially edentulous patients. Most implants were placed into compromised residual ridges or prepared tooth extraction sockets. Implants placed in augmented areas were splinted to implants in nonaugmented sites for stability. In all cases, beta-tricalcium phosphate was mixed with blood from the surgical site to augment the ridge level or fill spaces between the implant and socket wall. When indicated, the same materials were used for sinus floor augmentation. All implants were tapered screws with roughened surfaces, primarily (75%) from 1 manufacturer. One of the authors (Z.O.) prosthetically restored a total of 189 implants that were placed in 35 patients. In this group of patients, complete restorative data were available. All implants were monitored for 12-48 months (mean = 19.2; median = 24). RESULTS: A total of 1039 implants survived, and 26 failed, including 5 in the anterior mandible and 21 in the maxillae. In the restorative group, 186 implants survived, and 3 maxillary implants failed. All implant failures in this study occurred in the augmented sites. CONCLUSION: Within the limitations of this study, immediate loading of splinted implants in augmented sites is a predictable procedure.     

Identification of stability changes for immediately placed dental implants

PURPOSE: To evaluate the changes in stability of immediately placed implants over a 6-month healing period relative to implants placed in native bone and to compare the stability of 2 different implant designs when placed as immediate implants in extraction sites. MATERIALS AND METHODS: This prospective cohort study evaluated 3 implant patient populations. The control group (9 patients, 11 implants) required a single-stage, 1-piece, rough-surface implant (considered a "standard" implant) placed in nongrafted sites at least 6 months postextraction. The 2 experimental groups (25 patients, 28 implants) required extraction and immediate placement of either standard implants (12 patients) or tapered, self-tapping implants (13 patients). Immediate implant placement was carried out at the time of tooth extraction. Resonance frequency analysis (RFA), a measure of implant stability, was performed following implant placement at 2- to 4-week intervals for the first 16 weeks and at 24 weeks for immediate implants. RESULTS: Placement protocol (control versus immediate placement) resulted in significant (P < .001) differences in implant stability, even though there was no difference (P > .90) in initial, mechanical implant stability between these groups. The immediately placed implants had significantly greater reductions in stability, approximately 15%, from baseline to 4 weeks. Immediate implant stability was consistent with that of implants placed in native bone after 12 to 16 weeks. Implant design did not have a significant effect on stability. CONCLUSIONS: This study demonstrates that immediate placement protocols are viable options and that standard-design implants may provide levels of biologic stability similar to a tapered, self-tapping implant design in immediate placement protocols. Most importantly, this study documents high levels of metabolic activity in the supporting osseous tissue following immediate placement, which may extend time to restoration compared with traditional implant placement.     

Radiographic bone density around immediately loaded oral implants

OBJECTIVES: The aim of this study was to analyze the bone density around immediately loaded oral implants by a new volumetric CT scan (Maxiscan) and to compare it with that of unloaded implants. MATERIAL AND METHODS: Four patients with an age range from 44 to 65 years old were selected for this study. All the patients needed a prosthetic rehabilitation in partially edentulous posterior maxillas or mandibles. A total of 12 oral implants were placed in the four patients. Six of these implants were immediately loaded while six were left unloaded. Six months after placement, immediately loaded and unloaded oral implants were analyzed by a volumetric CT scan. RESULTS: The overall success rate in this study with immediately loaded oral implants was 100%. The radiological assessments showed that the mean densitometric profile, which is a measure of bone mineralization, was higher in the immediately loaded group than in the unloaded group. The differences observed between the two groups of oral implants (immediately loaded and unloaded) were statistically significant (P<0.05). The bone was significantly more dense around immediately loaded than unloaded oral implants on the basis of a radiological assessment. CONCLUSION: The innovative aspect of this clinical study is to propose a new method to analyze the bone density, reducing the need for histological analysis from human biopsy.     

Collagen fiber orientation in human peri-implant bone around immediately loaded and unloaded titanium dental implants

BACKGROUND: The main factor in determining the mechanical properties of bone is the collagen configuration. METHODS: This study investigated the birefringence in human bone around loaded and unloaded titanium dental implants to evaluate the collagen fiber orientation using circularly polarized light (CPL) and scanning electron microscopy (SEM). A total of 10 titanium dental implants, five immediately loaded and five unloaded, were used. The birefringence measurements were performed on digitized images of both loaded and unloaded implants. All images detected at 50x were measured using a software image analysis. RESULTS: In the bone around loaded implants, the transverse collagen fiber area was 45,481+/-3,037 pixel2 (mean+/-SD), while the area of longitudinal collagen fibers was 13,676+/-2,232 pixel2 (mean+/-SD). In the unloaded implants, the transverse collagen fiber area was 32,174+/-2,554 pixel2 (mean+/-SD), while the area of longitudinal collagen fibers was 89,073+/-1,960 pixel2 (mean+/-SD). The CPL measurements of the birefringence for transverse collagen fibers of loaded versus unloaded implants indicated that the differences were statistically significant (P <0.05). The results for the longitudinal collagen fibers of loaded versus unloaded implants were also statistically significant (P <0.05). CONCLUSIONS: In the bone around loaded dental implants, transverse collagen fibers were more abundant, while in the unloaded implants, collagen fibers run more longitudinally. The load seemed to determine the collagen fiber orientation.     

三种螺距对种植体初期稳定性影响的有限元研究

目的：利用即刻负载有限元模型,研究种植体不同螺纹螺距因素对初期稳定性的影响。方法：利用Pro／E软件、Hypermesh软件及ABAQUS有限元软件,建立四类种植体即刻负载的三维有限元模型,比较3种螺纹螺距（0．8mm、1．6mm、2．4mm）在分别垂直和水平加载时,对种植体初期稳定性的影响。结果：对不同螺纹螺距种植体来说,垂直加载和水平加载时0．8mm螺距螺纹种植体微动最小,2．4mm螺距螺纹种植体微动最大。结论：螺纹的螺距对垂直相对位移有影响,对水平相对位移影响不大。随着螺距的增加,种植体对抗垂直向载荷的抵抗力减弱。水平加载时,螺纹的螺距对颈部微动影响不明显。     

The radiographic bone loss pattern adjacent to immediately placed, immediately loaded implants

PURPOSE: The purpose of this study was to evaluate radiographic bone levels adjacent to implants placed in fresh extraction sockets (ESs) and immediately loaded with a fixed full-arch provisional restoration compared to bone levels adjacent to implants placed in native bone (NB) under the same restorative conditions. MATERIALS AND METHODS: Patients with a hopeless maxillary and/or mandibular dentition had their remaining teeth extracted and 6 to 8 implants placed and restored within 72 hours. Radiographs were obtained at time 0, 3 to 6 months, and annually for 5 years. The radiographs were digitized, and the bone level changes were measured using a computer-assisted method. RESULTS: A total of 139 implants, 42 ES and 97 NB, placed in 17 patients were evaluated. The overall results indicated that for all implants (ES + NB), 0.60+/-0.71 mm of bone was lost after 6 months; 1.17 +/-0.59 mm of bone was lost after 18 months; 0.87+/-0.76 mm bone was lost after 36 months; and 1.35 +/-0.42 mm of bone was lost after 60 months. When stratifying for NB versus ES implants, it was found that for NB implants, 0.75+/- 0.21 mm of bone was lost after 6 months; 1.31 +/- 0.91 mm of bone was lost after 12 months; 1.07+/-0.21 mm of bone was lost after 36 months; and 1.45 +/- 0.49 mm of bone was lost after 54 months. For ES implants, 0.14 +/-0.33 mm of bone was lost after 6 months; 1.02 +/-0.27 mm of bone was lost after 12 months; 0.86+/-0.42 mm of bone was lost after 36 months; and 1.30 +/-0.48 mm of bone was lost after 54 months. CONCLUSION: The combination of ES and NB implants can be immediately loaded with a fixed full-arch prosthesis and remain stable for greater than 5 years. The bone loss adjacent to these implants is similar to that seen surrounding those placed and restored using traditional protocols.     

Survival of immediately provisionalized dental implants placed immediately into fresh extraction sockets

BACKGROUND: The aim of this study was to evaluate the survival rate of immediately provisionalized dental implants immediately placed into fresh extraction sockets. METHODS: The study consisted of 87 consecutive patients, ranging in age from 21 to 76 years (average: 53.30 +/- 13.34 years), who received 210 immediately provisionalized, immediately placed dental implants between the years 2000 and 2005. Data were recorded regarding the survival rate of these implants and the incidence of complications. RESULTS: Follow-up ranged from 6 to 52 months (mean: 15.60 +/- 12.60 months). Smoking, past and present, was reported by 28.7% and 20.7% of patients, respectively. The maxillary incisors were replaced most frequently, followed by the mandibular lateral incisors. Most of the implants were >13 mm in length and > or = 3.75 mm in diameter. There were 47 (22.4%) single restored implants and 163 (77.6%) splinted implants. Overall, the implant survival rate was 97.6% (five implants failed). Complications, such as swelling, inflammation, and pain, were observed in 24 (11.4%) of the implants. No relation was found between complications and failure. The present study failed to reveal a relationship between implant survival rate and smoking, implant dimensions, and area of implantation. CONCLUSION: Immediately provisionalized immediate implants can serve as a predictable procedure with high survival rates.     

Outcomes of fixed prostheses supported by immediately loaded endosseous implants

PURPOSE: The aim of this article was to evaluate the survival and success of Straumann implants after immediate loading. A new method for fabricating effective definitive prostheses to immediately load implants in edentulous patients was presented. MATERIALS AND METHODS: Nine patients received 4 implants each, and resin-metal prostheses were installed less than 48 hours after implant placement. Mobility was evaluated immediately after the surgical procedures and 3 months subsequently using the Periotest. Clinical evaluation of soft peri-implant tissues was conducted monthly after the sutures were removed, and radiographs were obtained 6, 12, and 24 months after the surgery. RESULTS: The Periotest revealed statistical values that were stable, with no mobility. No signs of inflammation and/or bleeding were observed. The radiographs did not reveal any continuous areas of radiolucency beyond the first thread of the 36 implants after 24 months. None of them failed, and the success rate was 100%. DISCUSSION: It is possible to submit implants to immediate load without jeopardizing osseointegration if parameters are met, such as suitable bone quality and quantity, lack of unfavorable systemic and psychologic factors, lack of parafunctional habits, strict maintenance of prosthetic requirements, minimization of micromotion, and use of an appropriate surgical protocol. CONCLUSION: Under immediate load, osseointegration of implants is possible, and the method presented for the fabrication of resin-metal prostheses has been reliable and predictable.