The use of a xenogeneic collagen matrix at the time of implant placement to increase the volume of buccal soft tissue.

The purpose of this study was to evaluate the efficacy of Mucograft (MG; a porcine-derived purified collagen membrane) to increase the thickness and height of the buccal soft tissue when placed at the time of implant placement in patients with thin or deficient keratinized tissue (KT). The primary endpoint of the study was the change in thickness and height of the buccal KT. Secondary endpoints included stability of the midbuccal soft tissue level; clinician rating of color, texture, and contour of treatment site; probing pocket depths (PPDs); assessment of satisfaction outcome; and patient assessment of pain/discomfort. Thirty-two patients were enrolled and 31 patients completed the study. There were no statistically significant (SS) differences between the MG and control groups for height measures. There was no SS difference for KT thickness (P = .117) between the groups at the final measurement (3 months postsurgery). However, there was an SS difference (P = .009) in favor of the MG group when comparing the difference in presurgical KT thickness to that 3 months postsurgery. Thus, MG was successful (compared to the control) in increasing the buccal KT. There were no SS differences between the groups for any of the other endpoints, including color, texture, contour, and pain assessment at any visit or successful outcome between the treatment group and the control. More cases and longer follow-up of implants placed with MG are needed to verify the results of this randomized prospective study.

Tissue Healing Around Dental Implants With Marginal Bone Defects With and Without Flap Elevation: An Experimental Study in Dogs.

The technique of immediate implant placement after extraction has been conceived for preserving residual bone support and soft tissue morphology. Today, this procedure is still unpredictable and presents inconveniences for both the patient and the dentist. Therefore, the healing process around a dental implant placed into an extraction socket needs to be deeply investigated to increase the predictability of this surgical approach. The aim of the present investigation was to evaluate the healing of bone defects (fresh extraction sockets) after implant installation with flap elevation, and primary closure compared with implant installation without flap elevation. This study use histologic and histomorphometric analyses to evaluate tissue healing around dental implants with marginal bone defects with and without flap elevation 1 week, 4 weeks, and 12 weeks after implantation in the dogs. The main qualitative findings showed that after 1 week of implantation almost no bone repair was observed, and there was no significant difference between the 2 groups in terms of bone-healing performance, inflammatory infiltrates (slight to moderate grade), and bone resorption (moderate to marked grade) limited to the coronal portion of the implanted sites. The 2 groups with or without flap elevation behaved similarly at this point of implantation. Under the experimental conditions of this study, no biological differences were observed between the 2 groups with and without flap elevation in terms of crestal bone repair, inflammation, marginal bone loss, and soft tissue downgrowth. The qualitative differences observed might be imputable to fortuitous events. The histomorphometric measurements confirmed the qualitative trends observed. The limitations of this study, as with all animal studies, are its translational aspects. Investigation of the same topic in a human population by setting up a controlled, randomized, prospective trial including a sufficient amount of patients investigated according to the split-mouth method would be beneficial.

Effect of 3- and 4-mm interimplant distances on the height of interimplant bone crest: a histomorphometric evaluation measured on bone level dental implants in minipig.

PURPOSE: To analyze crestal bone loss changes that may affect the gingival height around an implant and bone loss in interproximal areas. When implants are placed adjacent to one another, interimplant bone loss around 1 implant may combine with the implant bone loss around the adjacent implant to affect the crestal bone loss interproximally. MATERIALS AND METHODS: The primary objective of this study was to evaluate histologically and histomorphometrically the effect that this implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by 2 different distances: 4 mm and 3 mm. A secondary objective was to evaluate the percentage of bone-to-implant contact, interproximal soft tissue height, location of the junctional epithelium, and length of connective tissue contact to abutment and/or implant, for the 2 different distances. RESULTS: Results showed that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 4 or 3 mm. In addition, the secondary objective parameters also demonstrated similar results between the 2 interimplant distances. CONCLUSION: This study showed that interimplant bone levels can usually be maintained at similar levels for 4- and 3-mm distances during at least 2 months.

Radiological and micro-computed tomography analysis of the bone at dental implants inserted 2, 3 and 4 mm apart in a minipig model with platform switching incorporated.

BACKGROUND: The purpose of this study was to assess the effect of inter-implant distance on interproximal bone utilizing platform switching. Analysis of interproximal bone usually depends on traditional two-dimensional radiographic assessment. Although there has been increased reliability of current techniques, there has been an inability to track bone level changes over time and in three dimensions. Micro-CT has provided three-dimensional imaging that can be used in conjunction with traditional two-dimensional radiographic techniques. METHODS: This study was performed on 24 female minipigs. Twelve animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 2 mm apart creating a split mouth design. Twelve other animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 4 mm apart creating a split mouth design too. The quantitative evaluation was performed comparatively on radiographs taken at t 0 (immediately after implantation) and at t 8 weeks (after termination). The samples were scanned by micro-computed tomography (µCT) to quantify the first bone to implant contact (fBIC) and bone volume/total volume (BV/TV). Mixed model regressions using the nonparametric Brunner-Langer method were used to determine the effect of inter-implant distance on the measured outcomes. RESULTS: The change in bone level was determined using radiography and its mean was 0.05 mm for an inter-implant distance of 3 and 0.00 mm for a 2 mm distance (P = 0.7268). The mean of this outcome was 0.18 mm for the 3 mm and for 4 mm inter-implant distance (P = 0.9500). Micro-computed tomography showed that the fBIC was always located above the reference, 0.27 and 0.20 mm for the comparison of 2-3 mm (P = 0.4622) and 0.49 and 0.34 mm for the inter-implant distance of 3 and 4 mm (P = 0.1699). BV/TV inside the defined parallelepipedic masks reached 82.38% for the 2 mm inter-implant distance and 85.00% for 3 mm, P = 0.8432. For the comparison of the 3-4 mm inter-implant distance, the means were 84.69% and 84.38%, respectively, P = 0.8401. Non-inferiority tests for the smaller inter-implant distances for both comparisons showed similar differences and similar tolerance ranges. CONCLUSION: The effect of a smaller interproximal distances between implants on bone level, fBIC and BV/TV assessed by two convergent investigation methods, radiology and µCT, was similar to that of larger distances. Implants can potentially be placed 2 mm apart instead of 3 mm and 3 mm apart instead of 4 mm when platform switching is utilized. Further research with a conventional platform is warranted.

A histomorphometric comparison of Bio-Oss alone versus Bio-Oss and platelet-derived growth factor for sinus augmentation: a postsurgical assessment.

The purpose of this study was to assess vital bone formation at 4 to 5 months and 7 to 9 months following sinus augmentation with anorganic bovine bone matrix (ABBM) with and without recombinant human platelet-derived growth factor (rhPDGF). Twenty-four subjects received bilateral sinus elevation surgery with ABBM on one side and ABBM and rhPDGF on the contralateral side. Twelve patients had core sampling at 4 to 5 months and 12 patients at 7 to 9 months postoperatively. In subjects with cores taken at 4 to 5 months, mean vital bone, connective tissue, and residual graft were 11.8%, 54.1%, and 33.6%, respectively, with ABBM alone. Cores of sinuses filled with ABBM and rhPDGF showed mean 21.1% vital bone, 51.4% connective tissue, and 24.8% residual graft. Paired t test showed a statistically significant difference in vital bone. In cores taken at 7 to 9 months, the values for ABBM alone and ABBM + rhPDGF were 21.4% vs 19.5% vital bone, 28.4% vs 44.2% connective tissue, and 40.3% residual graft vs 35.5%. There was no statistically significant difference in vital bone at 7 to 9 months after surgery. Test and control groups showed clinically acceptable levels of vital bone both at 4 to 5 months and 7 to 9 months postsurgery. However, vital bone formation was significantly greater in the 4- to 5-month sections of ABBM + rhPDGF vs the Bio-Oss alone. In the 7- to 9-month specimens, this difference disappeared. More rapid formation of vital bone with the addition of rhPDGF may allow for earlier implant placement.

Techniques to remove a failed integrated implant.

This literature and clinical review identifies and evaluates the various techniques for removing failed, fractured, or peri-implantitis-affected nonmobile implants. The article also discusses the limitations and complications that may arise with the various techniques during removal procedures. Based on specific clinical factors such as anatomical conditions, implant design, condition of implant connection, bone quality, and remaining amount of bone integrated to the implant body, a decision tree is proposed to help clinicians determine the most appropriate minimally invasive technique.

Effect of interimplant distance (2 and 3 mm) on the height of interimplant bone crest: a histomorphometric evaluation.

BACKGROUND: Implants restored according to a platform-switching concept (implant abutment interface with a reduced diameter relative to the implant platform diameter) present less crestal bone loss than implants restored with a standard protocol. When implants are placed adjacent to one another, this bone loss may combine through overlapping, thereby causing loss of the interproximal height of bone and papilla. The present study compares the effects of two interimplant distances (2 and 3 mm) on bone maintenance when bone-level implants with platform-switching are used. METHODS: This study evaluates marginal bone level preservation and soft tissue quality around a bone-level implant after 2 months of healing in minipig mandibles. The primary objective is to evaluate histologically and histomorphometrically the affect that an implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by two different distances. RESULTS: Results show that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 2 or 3 mm. The horizontal position of the bone relative to the microgap on platform level (horizontal component of crestal bone loss) was 0.31 ± 0.3 mm for the 2-mm interimplant distance and 0.57 ± 0.51 mm above the platform 8 weeks after implantation for the 3-mm interimplant distance. CONCLUSIONS: This study shows that interimplant bone levels can be maintained at similar levels for 2- and 3-mm distances. The horizontally displaced implant-abutment junction provided for a more coronal position of the first point of bone-implant contact. The study reveals a smaller horizontal component at the crest of bone than has been reported for non-horizontally displaced implant-abutment junctions.

A restoratively driven ridge categorization, as determined by incorporating ideal restorative positions on radiographic templates utilizing computed tomography scan analysis.

BACKGROUND: The introduction of implants into the field of dentistry has revolutionized the way we evaluate edentulous ridges. In an attempt to evaluate the deficient edentulous ridge, numerous classification systems have been proposed. Each of these classification systems implements a different approach for evaluating and planning treatment for the ridge deficiency. PURPOSE: The purpose of the present investigation was to propose a restoratively driven ridge categorization (RDRC) for horizontal ridge deformities based on an ideal implant position as determined through implant simulation, utilizing computed tomography (CT) scan images. MATERIALS AND METHODS: Radiographic templates were developed to capture the ideal restorative tooth position. Measurements were performed using CT scan software in a cross-sectional view and by virtual placement of a parallel-sided implant with a 3.25-mm diameter. RESULTS: Edentulous ridges were divided into five groupings: Group I, simulated implants with at least 2 mm of facial bone, accounted for 19.4% of ridges; Group II, simulated implant completely surrounded by bone, with less than 2 mm of facial plate thickness, accounted for 10.4% of ridges; Group III, wherein dehiscences are detected but no fenestrations are present, accounted for 33.3% of ridges; Group IV, wherein fenestrations are detected but no dehiscence is present, accounted for 6.3% of ridges; and Group V, wherein both dehiscences and fenestrations are present, accounted for 30.6% of ridges. CONCLUSION: The use of RDRC indicates that a high number of cases in the maxillary anterior area would require augmentation procedures in order to achieve ideal implant placement and restoration.

Distraction osteogenesis for ridge augmentation: prevention and treatment of complications. thirty case reports.

Distraction osteogenesis (DO) is the latest addition to the variety of alveolar ridge augmentation procedures used to increase the volume of bone prior to implant placement. Thirty DO procedures were performed in 30 patients using 17 intraosseous and 13 extraosseous devices to augment deficient alveolar ridges. Fifty-five implants placed in the distracted bone were followed for a period of 34 to 60 months after loading. Five implants failed, for a 90.9% success rate. Vertical augmentation ranged from 3.5 to 13.0 mm (average, 7.8 mm). At least one complication was encountered, requiring additional hard or soft tissue surgery, in each of the 30 reported cases. This paper reviews complications encountered in the DO-treated patients, suggesting solutions and measures to prevent these problems.

Histomorphometric comparison of a biphasic bone ceramic to anorganic bovine bone for sinus augmentation: 6- to 8-month postsurgical assessment of vital bone formation. A pilot study.

This blinded, randomized, controlled pilot investigation is the first to histomorphometrically compare vital bone formation following bilateral sinus grafting with a biphasic calcium phosphate (BCP) (Straumann Bone Ceramic) to an anorganic bovine bone matrix (ABBM) (Bio-Oss) 6 to 8 months following graft placement. Twelve patients were selected. Following elevation of the lateral sinus walls, one material was placed in the right sinus and the other material was placed in the left sinus, as determined by randomization. Six to 8 months after grafting (with the same time frame used for each patient), a trephine core was taken from the grafted area and sent for histomorphometric analysis. Cores were obtained from 21 healed sinuses in 12 patients. Nine patients provided bilateral cores. Histomorphometric analysis of 10 BCP cores and 11 ABBM cores revealed an average vital bone content of 28.35% and 22.27%, respectively. The average percentage of residual graft particles was 28.4% in the BCP cores and 26.0% in the ABBM cores. The difference in vital bone formation was not significantly different (n = 9 patients, paired t test) between bilateral sinuses treated with the BCP and those treated with the ABBM. Histologically, both materials appeared to be osteoconductive and support new bone formation. Future studies are needed to confirm the ability of this regenerated bone to support dental implant maintenance over time.

A two-stage full-arch ridge expansion technique: review of the literature and clinical guidelines.

Ridge expansion techniques have been acknowledged to offer several advantages in the correction of ridge deformities. The expanded defect heals in a similar manner to an extraction socket. In selected cases patients can wear their dentures after surgery. Secondary surgical sites are not a prerequisite, and simultaneous implant placement can be achieved during ridge expansion. The limitation of this technique lies in its inability to create bone vertically. Therefore, it is not indicated for the correction of vertical defects. The application of the split ridge expansion technique has been reported in the literature as it pertains to partially edentulous deficient ridges. The purpose of this article was to present the application of the split ridge expansion technique in the fully edentulous maxilla and discuss the distinction between the immediate or one-stage approach and the delayed or two-stage approach. Histologic results are discussed. Two case reports demonstrate the results that can be obtained with this technique.

Precision of flapless implant placement using real-time surgical navigation: a case series.

PURPOSE: To demonstrate the predictability of flapless surgery using navigation surgery. MATERIALS AND METHODS: Computer-generated preoperative implant planning was compared to actual placement by CT (computerized tomography) scanning of patients before and after surgery. Once pre- and postoperative coordinates of virtual implants were obtained, linear distances and angles were calculated. Coronal and apical errors consisted of the shortest distance from the preoperative planning to the postoperative overlay. RESULTS: Fourteen implants were placed in 6 patients who received CT scans before and after implant placement. Preoperative implant planning using software was compared to actual placement. The average discrepancy of the head of the implant was 0.89 mm +/- 0.53 SD (range, 0.32 to 1.96). The average discrepancy of the apex of the implant was 0.96 mm +/- 0.50 SD (range, 0.25 to 1.99). The average angle discrepancy and standard deviation were 3.78 degrees +/- 2.76 SD (range, 0.60 to 9.87). CONCLUSION: Optical computerized navigation is vulnerable to technological and technical errors. Yet, the present case series suggests that less than 1 mm of mean linear deviation and less than 4 degrees of angular deviation might be attainable.

Fixed and removable provisional options for patients undergoing implant treatment.

The provisional phase of treatment can be the most challenging aspect of implant dentistry. The techniques available today include removable, tooth-supported, and implant-retained provisional restorations. The selection of the type of provisional prosthesis should be based on esthetic demands, functional requirements, duration, and ease of fabrication. This article includes a review of 118 articles from peer-reviewed journals published in English from January 1986 to February 2007. This review was performed using MEDLINE. The indications, advantages, and disadvantages of the various provisional restorations are discussed.

Accurate transfer of peri-implant soft tissue emergence profile from the provisional crown to the final prosthesis using an emergence profile cast.

BACKGROUND: The use of impression copings to make the final impression results in a master cast in which the soft tissue configuration around the implant platform is circular. Therefore, any soft tissue sculpting developed clinically by the provisional restoration is squandered. PURPOSE: The purpose of this report was to present a method for the precise transfer of the peri-implant soft-tissue developed by a customized provisional restoration to an emergence profile cast. MATERIALS AND METHODS: The emergence profile cast is obtained from an impression of the implant-supported provisional restoration and poured with a soft tissue model material. It is used for the fabrication of the emergence profile of the implant abutment and the cervical section of the crown. CONCLUSION: The technique described is simple, accurate, predictable, and does not require additional chair time for the customization of the impression coping or the fabrication of a new provisional restoration. CLINICAL SIGNIFICANCE: This article describes a technique that results in an implant restoration that mimics accurately in its emergence profile that of the carefully crafted and customized provisional restoration. The reproduction of the soft tissue contour from the provisional to the final restoration results in an improved esthetic outcome of the final restoration.

Narrow-diameter implants: a restorative option for limited interdental space.

The present study reports on the results of the use of a screw-retained narrow-diameter implant (NDI) system as an option for implant placement in areas of limited bone volume. This retrospective report followed 48 NDIs in 27 patients for 1 to 5 years postloading. No implant failures were reported, yielding a 100% survival rate. The screw-retained attribute of this system allows retrievability of the restorations, which may require replacement because of porcelain fracture, chipping, or a desire to change color. The three diameters available--1.8 mm, 2.2 mm, and 2.4 mm--allow flexibility for a variety of narrow edentulous spaces. These NDIs present a cost-effective alternative for restoring limited spaces with implant restorations, without the bone augmentation or orthodontic procedures required for conventional fixed restorations. The NDI system is approved by the U.S. Food and Drug Administration for long-term use.

Immediate loading of narrow-diameter implants with overdentures in severely atrophic mandibles.

Oral rehabilitation using two to four implants to support mandibular overdentures has been shown to have success rates of approximately 96% with implants placed in a one- or two-stage procedure. The purpose of this study is to evaluate 10 consecutive cases of immediately loaded, narrow-diameter implants (NDIs) as support for overdentures in severely atrophic mandibles, and report on implant/prosthetic survival rates and patient satisfaction. Overall implant and prosthetic survival rates were 94.1% and 100%, respectively.

Advanced concepts in implant dentistry: creating the "aesthetic site foundation".

To obtain optimal and predictable aesthetics, deficiencies caused by soft and particularly hard tissue loss can be managed by various methods, such as orthodontic tooth eruption, socket preservation, and guided bone regeneration. However, in complex cases, these methods are often insufficient. Here, the authors introduce advanced concepts in aesthetic implant dentistry, such as "Aesthetic Site Foundation", "Aesthetic Guided Bone Regeneration" and "Implant Rectangle" that will guide the clinician in the quest to optimal aesthetic outcomes.

A simplified socket classification and repair technique.

UNLABELLED: Clinicians are often confronted with changes in the anatomy of the local site following tooth extraction. Successful management of the extraction socket can be challenging, particularly in the aesthetic zone. Proper management is necessary to ensure that the implant used to support a prosthesis will remain stable. This article will recommend a classification system for various types of extraction sockets. A simple, noninvasive approach to the grafting and management of sockets when soft tissue is present but the buccal plate is compromised following tooth extraction will also be discussed. LEARNING OBJECTIVES: This article discusses a classification system for extraction sockets and a noninvasive approach for grafting. Upon reading this article, the reader should: Understand the proposed classification system, which addresses three different types of sockets. Become more familiar with the steps involved in a socket-repair technique for Type II sockets.

Immediate implant placement and provisionalization--two case reports.

Endosseous dental implants have traditionally been placed using a two-stage surgical procedure with a 6- to 12-month healing period following tooth extraction. In order to decrease healing time, protocols were introduced that included immediate implant placement and provisionalization following tooth extraction. Although survival rates for this technique are high, postoperative gingival shrinkage and bone resorption in the aesthetic zone are potential limitations. The two case reports described herein present a surgical technique for the preservation of anterior aesthetics that combines minimally invasive extraction, immediate implant placement, provisionalization, and the use of implants with a laser micro-grooved coronal design.