Surgical Manual of Implant Dentistry: Step-by-Step Procedures

The purpose of this practical manual is to describe and illustrate each step of the basic surgical procedures involved in the placement of implants in qualified patients. To that end, each procedure is briefly but lucidly described; carefully illustrated in a series of drawings of the techniques and instrumentation used; and reinforced through clinical photographs, including radiographic and postoperative follow-up views. In addition to the basic implant surgical principles, evidence-based indications and procedures for guided bone regeneration in apical fenestration and crestal dehiscence defects, and for simultaneous sinus floor elevation via the lateral window and osteotome techniques are featured.

Implant Failure Predictors in the Posterior Maxilla: A Retrospective Study of 273 Consecutive Implants

Background: The goal of this study was to retrospectively analyze a cohort of 136 patients who underwent dental implant placement in the posterior maxilla at the University of Connecticut Health Center to assess and identify predictors for implant failure in the posterior maxilla. Methods: Data were retrieved from patient charts to identify subjects older than 21 years of age who received dental implant(s) in the posterior maxilla. Patients without a postoperative baseline radiograph were excluded. A recall radiograph was taken 3 to 6 months after implant placement. If there was no recall radiograph, the subject was contacted for a recall visit that included a clinical evaluation and radiographs to determine the implant status. Based on a univariate screening, variables considered potential implant failure predictors included gender, diabetes, smoking, implant length, implant diameter, membrane use, sinus-elevation technique, and surgical complications. These parameters were further assessed, and a multivariable logistic regression was performed with implant failure as a dependant variable. All tests of significance were evaluated at the 0.05 error level. Results: Two hundred seventy-three implants were placed in the posterior maxilla. Fourteen implants failed (early and late failures combined), resulting in a 94.9% overall survival rate. The survival rates for the sinus-elevation group and native bone group were 92.2% and 96.7%, respectively (P = 0.090). Based on the multivariable analysis, sinus floor-elevation procedures were not associated with increased risk for implant failure (P = 0.702). In contrast, smoking and surgical complications had a statistically significant effect on implant failure; the odds ratios for implant failure were 6.4 (P = 0.025) and 8.2 (P = 0.004), respectively. Conclusion: Sinus-elevation procedures with simultaneous or staged implant placement do not increase the risk for implant failure, whereas smoking and surgical complications markedly increase the risk for implant failure.

Prosthetically driven, computer-guided implant planning for the edentulous maxilla: a model study

OBJECTIVES: To analyze computer-assisted diagnostics and virtual implant planning and to evaluate the indication for template-guided flapless surgery and immediate loading in the rehabilitation of the edentulous maxilla. MATERIALS AND METHODS: Forty patients with an edentulous maxilla were selected for this study. The three-dimensional analysis and virtual implant planning was performed with the NobelGuide software program (Nobel Biocare, Göteborg, Sweden). Prior to the computer tomography aesthetics and functional aspects were checked clinically. Either a well-fitting denture or an optimized prosthetic setup was used and then converted to a radiographic template. This allowed for a computer-guided analysis of the jaw together with the prosthesis. Accordingly, the best implant position was determined in relation to the bone structure and prospective tooth position. For all jaws, the hypothetical indication for (1) four implants with a bar overdenture and (2) six implants with a simple fixed prosthesis were planned. The planning of the optimized implant position was then analyzed as follows: the number of implants was calculated that could be placed in sufficient quantity of bone. Additional surgical procedures (guided bone regeneration, sinus floor elevation) that would be necessary due the reduced bone quality and quantity were identified. The indication of template-guided, flapless surgery or an immediate loaded protocol was evaluated. RESULTS: Model (a) - bar overdentures: for 28 patients (70%), all four implants could be placed in sufficient bone (total 112 implants). Thus, a full, flapless procedure could be suggested. For six patients (15%), sufficient bone was not available for any of their planned implants. The remaining six patients had exhibited a combination of sufficient or insufficient bone. Model (b) - simple fixed prosthesis: for 12 patients (30%), all six implants could be placed in sufficient bone (total 72 implants). Thus, a full, flapless procedure could be suggested. For seven patients (17%), sufficient bone was not available for any of their planned implants. The remaining 21 patients had exhibited a combination of sufficient or insufficient bone. DISCUSSION: In the maxilla, advanced atrophy is often observed, and implant placement becomes difficult or impossible. Thus, flapless surgery or an immediate loading protocol can be performed just in a selected number of patients. Nevertheless, the use of a computer program for prosthetically driven implant planning is highly efficient and safe. The three-dimensional view of the maxilla allows the determination of the best implant position, the optimization of the implant axis, and the definition of the best surgical and prosthetic solution for the patient. Thus, a protocol that combines a computer-guided technique with conventional surgical procedures becomes a promising option, which needs to be further evaluated and improved.

Anatomical characteristics and dimensions of edentulous sites in the posterior maxillae of patients referred for implant therapy

The purpose of this study was to analyze the width and height of edentulous sites in the posterior maxilla using cone beam computed tomography (CBCT) images from patients referred for implant therapy. A total of 122 CBCT scans were included in the analysis, resulting in a sample size of 252 edentulous sites. The orofacial crest width was measured in coronal slices, perpendicular to the alveolar ridge. The bone height was analyzed in the respective sagittal slices. Additionally, the following secondary outcome parameters were evaluated: the morphology of the sinus floor, the presence of septa in the maxillary sinus, and the thickness of the sinus membrane. The mean crest width for all analyzed sites was 8.28 mm, and the mean bone height was 7.22 mm. The percentage of patients with a crest width of less than 6 mm was 27% in premolar sites and 7.8% in molar sites. The bone height decreased from premolar to molar areas, with a high percentage of first and second molar sites exhibiting a bone height of less than 5 mm (54.12% and 44.64%, respectively). Regarding the morphology of the sinus floor, 53% of the edentulous sites exhibited a flat configuration. A septum was present in 67 edentulous sites (26.59%). Analysis of the sinus membrane revealed 88 sites (34.9%) with increased mucosal thickness (> 2 mm). For the crest width, the location of the edentulous site and the morphology of the sinus floor were both statistically significant variables. For the crest width and mean bone height, the location of the edentulous site and the morphology of the sinus floor were both statistically significant variables. The study confirmed that a high percentage of edentulous sites in the posterior maxilla do require sinus floor elevation to allow the placement of dental implants. Therefore, a detailed three-dimensional radiograph using CBCT is indicated in most patients for proper treatment planning.

Optimal number of oral implants for fixed reconstructions: a review of the literature.

BACKGROUND AND AIM So far there is little evidence from randomised clinical trials (RCT) or systematic reviews on the preferred or best number of implants to be used for the support of a fixed prosthesis in the edentulous maxilla or mandible, and no consensus has been reached. Therefore, we reviewed articles published in the past 30 years that reported on treatment outcomes for implant-supported fixed prostheses, including survival of implants and survival of prostheses after a minimum observation period of 1 year. MATERIAL AND METHODS MEDLINE and EMBASE were searched to identify eligible studies. Short and long-term clinical studies were included with prospective and retrospective study designs to see if relevant information could be obtained on the number of implants related to the prosthetic technique. Articles reporting on implant placement combined with advanced surgical techniques such as sinus floor elevation (SFE) or extensive grafting were excluded. Two reviewers extracted the data independently. RESULTS A primary search was broken down to 222 articles. Out of these, 29 studies comprising 26 datasets fulfilled the inclusion criteria. From all studies, the number of planned and placed implants was available. With two exceptions, no RCTs were found, and these two studies did not compare different numbers of implants per prosthesis. Eight studies were retrospective; all the others were prospective. Fourteen studies calculated cumulative survival rates for 5 and more years. From these data, the average survival rate was between 90% and 100%. The analysis of the selected articles revealed a clear tendency to plan 4 to 6 implants per prosthesis. For supporting a cross-arch fixed prosthesis in the maxilla, the variation is slightly greater. CONCLUSIONS In spite of a dispersion of results, similar outcomes are reported with regard to survival and number of implants per jaw. Since the 1990s, it was proven that there is no need to install as many implants as possible in the available jawbone. The overwhelming majority of articles dealing with standard surgical procedures to rehabilitate edentulous jaws uses 4 to 6 implants.

Mesenchymal Stem Cells and Bovine Bone Mineral in Sinus Lift Procedures-An Experimental Study in Sheep

Introduction: New reconstructive and less invasive methods have been searched to optimize bone formation and osseointegration of dental implants in maxillary sinus augmentation. Purpose: The aim of the presented ovine split-mouth study was to compare bovine bone mineral (BBM) alone and in combination with mesenchymal stem cells (MSCs) regarding their potential in sinus augmentation. Material and Methods: Bilateral sinus floor augmentations were performed in six adult sheep. BBM and MSCs were placed into the test side and only BBM in the contra-lateral control side of each sheep. Animals were sacrificed after 8 and 16 weeks. Augmentation sites were analyzed by computed tomography, histology, and histomorphometry. Results: The initial volumes of both sides were similar and did not change significantly with time. A tight connection between the particles of BBM and the new bone was observed histologically. Bone formation was significantly (p = 0.027) faster by 49% in the test sides. Conclusion: The combination of BBM and MSCs accelerated new bone formation in this model of maxillary sinus augmentation. This could allow early placement of implants.

Histological findings following the use of a space-making device for bone reformation and implant integration in the maxillary sinus of primates

Background: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants. Purpose: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants. Materials and Methods: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell™ (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections. Results: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity. Conclusions: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results. © 2009, Wiley Periodicals, Inc.

Effectiveness of Piezoelectric Surgery in Preparing the Lateral Window for Maxillary Sinus Augmentation in Patients with Sinus Anatomical Variations: A Case Series

Purpose: The present article sought to evaluate the effectiveness of a piezoelectric surgical unit for maxillary sinus augmentation surgeries in avoiding perforation of the sinus membrane and other possible procedural complications in patients with anatomical variations of the sinus. Materials and Methods: Twenty-five patients presenting sinus anatomical variations, who were indicated for a total of 40 sinus grafting procedures performed by the lateral window approach with a piezoelectric device, were analyzed. After 6 months of healing, implants were placed. Information collected included clinical and computed tomographic information on anatomical variations in the sinus bone walls, in the size of the sinus, and in the thickness of the sinus membrane. Occurrence of sinus membrane perforation and computed tomographic measurements of the amount of bone height gained with the grafting procedures were also recorded. Results: Only two patients presented a small perforation (less than 5 mm in diameter) of the sinus membrane, which occurred only after osteotomies of the lateral windows and did not compromise the surgical outcome. No implants were lost during a mean follow-up period of 19 months. Conclusion: The use of piezoelectric surgery allowed for the accomplishment of all rehabilitation treatments within the follow-up period of this study. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:1211-1215

Mesenchymal stem cells and inorganic bovine bone mineral in sinus augmentation: comparison with augmentation by autologous bone in adult sheep

Our aim was to compare the osteogenic potential of mononuclear cells harvested from the iliac crest combined with bovine bone mineral (BBM) (experimental group) with that of autogenous cancellous bone alone (control group). We studied bilateral augmentations of the sinus floor in 6 adult sheep. BBM and mononuclear cells (MNC) were mixed and placed into one side and autogenous bone in the other side. Animals were killed after 8 and 16 weeks. Sites of augmentation were analysed radiographically and histologically. The mean (SD) augmentation volume was 3.0 (1.0) cm(3) and 2.7 (0.3) cm(3) after 8 and 16 weeks in the test group, and 2.8 (0.3) cm(3) (8 weeks) and 2.8 (1.2) cm(3) (16 weeks) in the control group, respectively. After 8 weeks, histomorphometric analysis showed 24 (3)% BBM, and 19 (11)% of newly formed bone in the test group. The control group had 20 (13%) of newly formed bone. Specimens after 16 weeks showed 29 (12%) of newly formed bone and 19 (3%) BBM in the test group. The amount of newly formed bone in the control group was 16 (6%). The results show that mononuclear cells, including mesenchymal stem cells, in combination with BBM as the biomaterial, have the potential to form bone. (C) 2009 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

VEGF and MVD expression in sinus augmentation with autologous bone and several graft materials

The aim of this study was to assess vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) in maxillary sinus augmentation with autogenous bone and different graft materials for evaluating their angiogenic potential.Biopsies were harvested 10 months after sinus augmentation with a combination of autogenous bone and different graft materials: hydroxyapatite (HA, n = 6 patients), demineralized freeze-dried bone allograft (DFDBA, n = 5 patients), calcium phosphate (CP, n = 5 patients), Ricinus communis polymer (n = 5 patients) and control group - autogenous bone only (n = 13 patients).In all the samples, higher intensities of VEGF expression were prevalent in the newly formed bone, while lower intensities of VEGF expression were predominant in the areas of mature bone. The highest intensity of VEGF expression in the newly formed bone was expressed by HA (P < 0.001) and CP in relation to control (P < 0.01) groups. The lowest intensities of VEGF expression in newly formed bone were shown by DFDBA and polymer groups (P < 0.05). When comparing the different grafting materials, higher MVD were found in the newly formed bone around control, HA and CP (P < 0.001).Various graft materials could be successfully used for sinus floor augmentation; however, the interactions between bone formation and angiogenesis remain to be fully characterized.

Immediate reconstruction of frontal sinus fractures: review of 26 cases

Purpose: the purpose of this study was to evaluate complications occurring after immediate reconstruction of severe frontal sinus fractures, including cases where the fracture was not limited to the anterior wall and also involved the posterior wall and/or sinus floor.Patients and Methods: the records of twenty-six patients presently undergoing follow-up for frontal sinus fracture reconstruction were reviewed. Information regarding demographics, fracture characteristics and causes, associated facial fractures, use of grafts or implants, type of fixation used, nasofrontal duct management, use of antibiotics, and complications were noted. Patients were asked to return for clinical and radiographic follow-up to access late complications.Results: the average age of patients with frontal fractures was 29.1 years and 92.3% were male. Mean follow-up was 3.6 years. The most common causes of fracture were motor vehicle accidents and physical aggression. All patients presented with comminuted and dislocated anterior wall fractures, 34.6% presented with posterior wall fractures, and 46% had sinus floor fractures. Complications occurred in 7 patients (26.92%) and included pneumoencephalus, frontal cutaneous fistula, frontal bone irregularity, and sinusitis.Conclusions: Frontal sinus reconstruction is a good procedure for immediate fracture treatment if there is not excessive comminution, dislocation, or instability of the posterior wall and if the frontonasal duct area is intact or can be repaired. Most complications result from incorrect indication for reconstruction. (C) 2004 American Association of Oral and Maxillofacial Surgeons.

PLA/PGA copolymer as a bone substitute in maxillary sinus augmentation: histological, histometric and immunohistochemistry study in rabbits

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Periapical surgery and the maxillary sinus: radiographic parameters for clinical outcome

OBJECTIVE: To find out whether conventional periapical radiographs can be used to determine the risk of creating an oroantral communication (OAC) while performing periapical surgery on maxillary premolars and molars. STUDY DESIGN: One hundred thirteen periapical radiographs of maxillary premolars and molars with periapical radiolucencies indicating chronic apical periodontitis were retrospectively analyzed and classified. The surgery reports were evaluated for occurrence of perforation of the maxillary sinus and postoperative complications. RESULTS: Perforation of the sinus membrane (also referred to as the Schneiderian membrane) occurred in 12 cases (9.6%). Exposure of the membrane without rupture occurred in 15 cases (12%). It was found that the distance between the apex or the periapical lesion and the sinus floor did not serve as a predictor of a possible sinus membrane rupture. On the other hand, if the radiograph showed a distinct distance between the lesion and the sinus floor, there was an 82.5% probability that OAC would not occur. Additionally, a blurred radiographic outline of the periapical lesion did not indicate an increased risk of sinus membrane rupture. CONCLUSION: Conventional periapical radiographs cannot be used as predictors for perforation of the maxillary sinus during periapical surgery. However, radiographs with a specific distance between the periapical lesion and the sinus floor point toward a very low risk of accidental sinus perforation during periapical surgery.

Maxillary sinus grafting with Bio-Oss or Straumann Bone Ceramic: histomorphometric results from a randomized controlled multicenter clinical trial

INTRODUCTION: This investigation was designed to compare the histomorphometric results from sinus floor augmentation with anorganic bovine bone (ABB) and a new biphasic calcium phosphate, Straumann Bone Ceramic (BCP). MATERIALS AND METHODS: Forty-eight maxillary sinuses were treated in 37 patients. Residual bone width was > or =6 mm and height was > or =3 mm and <8 mm. Lateral sinus augmentation was used, with grafting using either ABB (control group; 23 sinuses) or BCP (test group; 25 sinuses); sites were randomly assigned to the control or test groups. After 180-240 days of healing, implant sites were created and biopsies taken for histological and histomorphometric analyses. The parameters assessed were (1) area fraction of new bone, soft tissue, and graft substitute material in the grafted region; (2) area fraction of bone and soft tissue components in the residual alveolar ridge compartment; and (3) the percentage of surface contact between the graft substitute material and new bone. RESULTS: Measurable biopsies were available from 56% of the test and 81.8% of the control sites. Histology showed close contact between new bone and graft particles for both groups, with no significant differences in the amount of mineralized bone (21.6+/-10.0% for BCP vs. 19.8+/-7.9% for ABB; P=0.53) in the biopsy treatment compartment of test and control site. The bone-to-graft contact was found to be significantly greater for ABB (48.2+/-12.9% vs. 34.0+/-14.0% for BCP). Significantly less remaining percentage of graft substitute material was found in the BCP group (26.6+/-5.2% vs. 37.7+/-8.5% for ABB; P=0.001), with more soft tissue components (46.4+/-7.7% vs. 40.4+/-7.3% for ABB; P=0.07). However, the amount of soft tissue components for both groups was found not to be greater than in the residual alveolar ridge. DISCUSSION: Both ABB and BCP produced similar amounts of newly formed bone, with similar histologic appearance, indicating that both materials are suitable for sinus augmentation for the placement of dental implants. The potential clinical relevance of more soft tissue components and different resorption characteristics of BCP requires further investigation.

Osseointegração de implantes usinados e oxidados em seio maxilar preenchido por coágulo com ou sem osso autógeno: estudo histológico, histométrico e de RFA em macacos

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