Clinical radiographic, and histologic evaluation of maxillary bone reconstruction by using a titanium mesh and autogenous iliac graft: a case report

Stress Distribution Pattern in Zygomatic Implants Supporting Different Superstructure Materials

The aim of this study was to assess and compare the stress–strain pattern of zygomatic dental implants supporting different superstructures using 3D finite element analysis (FEA). A model of a tridimensional edentulous maxilla with four dental implants was designed using the computer-aided design (CAD) software. Two standard and two zygomatic implants were positioned to support the U-shaped bar superstructure. In the computer-aided engineering (CAE) software, different materials have been simulated for the superstructure: cobalt–chrome (CoCr) alloy, titanium alloy (Ti), zirconia (Zr), carbon-fiber polymers (CF) and polyetheretherketone (PEEK). An axial load of 500 N was applied in the posterior regions near the zygomatic implants. Considering the mechanical response of the bone tissue, all superstructure materials resulted in homogeneous strain and thus could reconstruct the edentulous maxilla. However, with the aim to reduce the stress in the zygomatic implants and prosthetic screws, stiffer materials, such Zr, CoCr and Ti, appeared to be a preferable option.

Prosthetically CAD-CAM–Guided Bone Augmentation of Atrophic Jaws Using Customized Titanium Mesh: Preliminary Results of an Open Prospective Study

This study evaluated the outcomes of computer-aided design–computer-aided machining (CAD-CAM)–customized titanium mesh used for prosthetically guided bone augmentation related to the occlusion-driven implant position, to the vertical bone volume gain of the mandible and maxilla, and to complications, such as mesh exposure. Nine patients scheduled for bone augmentation of atrophic sites were treated with custom titanium mesh and particulate bone grafts with autologous bone and anorganic bovine bone in a 1:1 ratio prior to implant surgery. The bone volume needed to augment was virtually projected based on implant position, width, and length, and the mesh design was programmed for the necessary retaining screws. After 6 to 8 months, bone augmentations of 1.72 to 4.1 mm (mean: 3.83 mm) for the mandibular arch and 2.14 to 6.88 mm (mean: 3.95 mm) for the maxilla were registered on cone-beam computerized tomography. Mesh premature (within 4 to 6 weeks) exposure was observed in 3 cases and delayed (after 4 to 6 weeks) in 3 other cases. One titanium mesh was removed before the programmed time but in all augmented sites was possible implant insertion. No complication occurred during prosthetic follow-up. Using CAD-CAM technology for prosthetically guided bone augmentation showed important postoperative morbidity of mesh exposure (66%). Because of this high prevalence of mesh exposure and the potential infection that could affect the expected bone augmentation, this study suggests a cautious approach to this procedure when designing the titanium mesh, to avoid flap tension that may cause mucosal rupture.

Radiographic analysis of dental implant extensions using bone grafts on dogs

BACKGROUND

Despite the wide use of dental implants they can bring inconveniences, as the moment one reaches osseointegration, these can no longer be extended. Therefore, if a problem occurs regarding its positioning, the options open are substitution or burial of the implant. With implant substitution, there exists the risk of local bone loss and/or future loss of the new implant.

PURPOSE

This study proposes a new device (implant extender) for extending the dental implant. The feasibility of this technique is verified through installing dental implant extensions onto the humerus bone of dogs with autogenous bone grafts.

MATERIALS AND METHODS

Implants of 3.3 mm in diameter by 6 mm in length and implant extensions with a 3.3 mm diameter and 2.2 mm length were installed onto humerus of 4 healthy dogs, using an autogenous bone graft in a block made from ilium. The biomechanical percussion tests were performed on the implant extensions and then the implant-extension sets were removed for radiographic analysis.

RESULTS

In the biomechanical percussion, none of the extensions present clinical mobility. As for the x-rays, these were analyzed by 20 professionals, who concluded that there was a 100% success rate with bone formation around the implants, 74.1% for bone neoformation of the implant extensions, and 80.1% referring to the adaptation of the implant extension.

DISCUSSION AND CONCLUSION

Bone formation occurred in every installed dental implant. In most cases, there occurred bone neoformation of the extensions and adaptation of the extension/implant set, according to the x-ray analysis performed by the evaluators. An absence of clinical mobility in the extensions was also observed. Although the results were promising, these techniques still need to be researched in humans, as an alternative for reducing elongated prosthetic crowns or poorly installed implants, as well as the modification of the type of implants among other applications.

The influence of initial alveolar ridge defect morphology on the outcome of implants in augmented atrophic posterior mandible: an exploratory retrospective study

OBJECTIVES

Clinicians commonly consider atrophic site topography as an important determinant in deciding the augmentation technique to utilize, as well as forecasting the likelihood of success. The purpose of this retrospective study was to examine the influence of initial atrophic posterior mandible morphology on the outcome of implants placed following augmentation.

MATERIALS AND METHODS

A total of 52 patients contributed 71 edentulous sites, and 185 implants were placed with mean follow-up of 37.97 months. The initial defect morphology was classified according to ABC classification (Journal of Oral Implantology, 37, 2013a and 361). Ridge augmentation was performed by "cortical autogenous tenting" (CAT) followed by either simultaneous or delayed implant placement after 4-6 months of healing. The European Academy of Osseointegration success criteria were used to evaluate implant outcomes.

RESULTS

The overall survival and success rates of dental implants were 98.91% and 80%, respectively. Cumulative success and survival rates in CAT group were 95% and 100% after 2 years of follow-up. The highest marginal bone loss (MBL) was observed (1.26 mm ± 0.99) around implants placed in augmented edentulous sites with initially narrow and flat alveolar crest (defect class CII). Conversely, least MBL (0.48 mm ± 0.78) was detected around implants placed into edentulous sites with two sloped boney walls (defect class AII). Differences between MBL observed around implants placed into initial defect class C, initial defect type and class A (I, II), as well as class BII, were statistically significant (P < 0.05). Among all implants, 148 were considered as successful, 26 exhibited satisfactory survival, nine with compromised survival, and two implants failed.

CONCLUSION

The present data confirmed the effect of initial ridge morphology on the outcome of implants placed into augmented bone. Specifically, class A and class B atrophic ridge defects, with one and two vertical boney walls, respectively, may be considered as more favorable recipient sites than class C defects with flat morphology. This conclusion is based on least MBL around implants placed into initial defect class A and class B augmented sites, and higher MBL in implants placed into class C recipient sites. A randomized controlled trial is warranted to examine these exploratory observations.

Predictability of staged localized alveolar ridge augmentation using a micro titanium mesh

PURPOSE

The aim of this study is to retrospectively evaluate the success rate of staged localized alveolar ridge augmentation using titanium micromesh. In addition, the factors that influenced the success were analyzed.

METHODS

Twenty-three alveolar ridges (posterior mandible 12, anterior maxilla 7, anterior and posterior maxilla 3, and posterior maxilla 1) were augmented using titanium micromesh and were retrospectively assessed.

RESULTS

Thirty sites were judged as successful with a success rate of 56.6 % (posterior mandible 58.3 %, anterior maxilla 57.1 %, anterior and posterior maxilla 33.3 %, and posterior maxilla 100 %). The span of the augmentation site was significantly correlated with the success rate (goodness test of fit for chi-square, p < 0.05). The success rate was low if infection of the grafted material was observed, while the exposure of titanium mesh had no negative impact.

CONCLUSIONS

This limited study suggested that the predictability of augmented bone volume in staged alveolar ridge augmentation using titanium micromesh was not sufficient to expect an ideal and planned implant placement. The success was influenced by the distance of the augmentation site and the infection of the graft material, which were associated with moderate to severe vertical ridge resorption and/or mechanical and functional loading on the surgical site.

Clinical Importance of Recipient Site Characteristics for Vertical Ridge Augmentation: A Systematic Review of Literature and Proposal of a Classification

This review evaluated the characteristics of vertical alveolar defects that were augmented via onlay bone grafting or guided bone regeneration. Information regarding the anatomic site, type of edentulism, and defects' dimensions were extracted. The experiments differed vastly in the description of the defects' features. Aiming to mitigate the confounding effect of recipient site's morphology in future experiments, a classification of vertically deficient recipient sites is proposed.

Rehabilitation of deficient alveolar ridges using titanium grids before and simultaneously with implant placement: a systematic review

BACKGROUND

The aim of the present study is to perform a systematic review of the literature on the use of titanium grids for implant surgery before and simultaneously with implant placement and to assess the success rate of the procedure, as well as survival and success rates of implants placed in the regenerated areas.

METHODS

Medline was used to identify studies in English published from 1996 to 2011. An additional hand search was performed of the relevant journals and of the bibliographies of the papers identified. Articles retrieved by two independent authors were screened using specific inclusion criteria: randomized controlled trials (RCTs), controlled clinical trials, and prospective clinical studies regarding vertical and/or horizontal regeneration of the alveolar ridge using titanium grids, in association or not with biomaterials, before and simultaneously with implant placement.

RESULTS

Six articles were selected, including a total of 79 patients, 87 titanium grids, and 141 implants. Twenty-four implants were placed simultaneously with titanium grids, and 117 implants were inserted after a period of 4 to 9 months. Titanium grids in combination with autogenous bone were used in 43 cases, 25 in combination with a mixture of autogenous bone and bone substitutes, 14 in association with bone substitutes, five using only titanium grids. The overall success rate of the regenerative procedures was 98.86%; the overall survival and success rates of implants were 100% and 93.2%, respectively.

CONCLUSIONS

The main limit of the present systematic review is the scarcity of papers with an adequate and consistent methodology regarding the data collection and analysis and the lack of RCTs and large well-designed long-term trials. Survival and success rates of implants placed in the areas treated with titanium grids were comparable to those of implants placed in native, non-regenerated bone and of implants placed in bone regenerated with resorbable and non-resorbable membranes.

Use of titanium mesh in lieu of a fixation screw to stabilize an autogenous block graft: a case report

Localized alveolar augmentation is carried out either before, during, or sometimes after implant placement. The placement of autogenous graft as a block or a particulate alone or in combination with an organic bone mineral has been practiced with a great deal of success. The block graft is secured in place with a screw and protected by a membrane. This case report describes the treatment of a female patient with a bucco-lingual bone deficiency grafted with autogenous block and a titanium mesh. Five months later, implant was placed in the grafted area. The definitive prosthesis was cemented 6 months later and followed up for 2 years.

Accuracy evaluation of computed tomography-derived stereolithographic surgical guides in zygomatic implant placement in human cadavers

Presurgical planning is essential to achieve esthetic and functional implants. For implant planning and placement, the association of computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional determination of the patient's anatomy and fabrication of both anatomic models and surgical guides. The goal of this clinical study was to determine the angular deviations between planned and placed zygomatic implants using stereolithographic surgical guides in human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A new CT scan was made after implant insertion. The angle between the long axis of the planned and actual implants was calculated. The mean angular deviation of the long axis between the planned and placed implants was 8.06 ± 6.40 (mean ± SD) for the anterior-posterior view, and 11.20 ± 9.75 (mean ± SD) for the caudal-cranial view. Use of the zygomatic implant, in the context of this protocol, should probably be reevaluated because some large deviations were noted. An implant insertion guiding system is needed because this last step is carried out manually. It is recommended that the sinus slot technique should be used together with the CT-based drilling guide to enhance final results. Further research to enhance the precision of zygomatic implant placement should be undertaken.

The relevance of Choukroun's platelet-rich fibrin and metronidazole during complex maxillary rehabilitations using bone allograft. Part I: a new grafting protocol

Extensive bone grafting remains a delicate procedure, because of the slow and difficult integration of the grafted material into the physiological architecture. The recent use of platelet concentrates aims to improve this process of integration by accelerating bone and mucosal healing. Choukroun's platelet-rich fibrin (PRF) is a healing biomaterial that concentrates in a single autologous fibrin membrane, most platelets, leukocytes, and cytokines from a 10 mL blood harvest, without artificial biochemical modification (no anticoagulant, no bovine thrombin). Whether used as a membrane or as fragments, PRF allows a significant postoperative protection of the surgical site and seems to accelerate the integration and remodeling of the grafted biomaterial. These properties are particularly helpful for vestibular bone grafting on the alveolar ridges. Moreover, it provides a very high quality of gingival maturation.A small quantity of a 0.5% metronidazole solution (10 mg) can also be used to provide an efficient protection of the bone graft against unavoidable anaerobic bacterial contamination. This article describes a new technique of total maxillary preimplant bone grafting using allograft, Choukroun's PRF membranes and metronidazole. This first part focused on the preimplant reconstructive treatment using allogeneic bone granules. PRF membranes are particularly helpful to protect the surgical site and foster soft tissue healing. This fibrin biomaterial represents a new opportunity to improve both the maturation of bone grafts and the final esthetic result of the peri-implant soft tissue.

Vertical alveolar ridge augmentation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement

OBJECTIVE

The aim of this study was to evaluate the combined use of autogenous bone and platelet-enriched fibrin glue as grafting material for vertical alveolar ridge augmentation with simultaneous implant placement in a canine alveolar ridge defect model.

STUDY DESIGN

In 6 mongrel dogs, bilateral vertical alveolar ridge defects were created in the mandible. After 3 months of healing, 2 dental implants were placed in each defect of the mandible, creating 6-mm supra-alveolar peri-implant defects. The 2 implants per defect were subjected to surgical treatments involving either a combination of autogenous bone grafts and platelet-enriched fibrin glue, or a conventional flap procedure only (control). After a healing period of 6 months, the dogs were humanely killed for histological and histometric analyses.

RESULTS

Implant placement alone produced limited vertical alveolar height (0.6 +/- 0.4 mm). However, alveolar augmentation including a combination of autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement resulted in alveolar ridge augmentation amounting to 4.2 +/- 1.0 mm, comprising 63% of the defect height. New bone-implant contact was 40.5% in the defects treated with combined autogenous bone grafts and platelet-enriched fibrin glue, and was 48.4% in the resident bone; this difference was not statistically significant.

CONCLUSION

The present study demonstrates that vertical alveolar ridge augmentation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement might effectively increase vertical alveolar ridge height and allow for an acceptable level of osseointegration.

Immediate function in the atrophic maxilla using zygoma implants: a preliminary study

STATEMENT OF PROBLEM

Oral rehabilitation of the edentulous atrophic maxilla to allow placement of a fixed dental prosthesis remains a challenge, especially if immediate function is provided.

PURPOSE

The aim of this retrospective, preliminary study was to evaluate, after a period of a 6 to 29 months' follow-up of prosthetic loading, the survival rate of 36 immediately loaded zygomatic implants placed in 18 atrophied maxillae.

MATERIAL AND METHODS

Eighteen consecutive patients (6 men and 12 women), with an average age of 58 years (range of 44-74 years), were followed up to 29 months (average of 14 months). The clinical criteria included stability of the implants and the prosthesis, resonance frequency analysis (RFA), and evaluation of swelling, pain, or discomfort. Radiographic analysis was completed for conventional implants, but not for zygoma implants. All patients had a fixed prosthesis screwed onto implants within 48 hours after implant placement. Descriptive statistics were used to analyze the data.

RESULTS

No zygomatic implants were lost over the observation period. Survival rate was 100% over an average 14-month observation period. Three conventional implants were lost, resulting in a survival rate of 95.6%. All the provisional prostheses were stable, and no relevant complications were noted.

CONCLUSIONS

The use of zygoma implants, together with conventional implants, in severely resorbed maxilla, appears to be a reliable technique for providing immediate function to patients.

Use of Titanium Mesh for Staged Localized Alveolar Ridge Augmentation: Clinical and Histologic-Histomorphometric Evaluation

The use of titanium mesh for localized alveolar ridge augmentation was evaluated by clinical, radiographic, laboratory, and histologic-histomorphometric evaluation. Seventeen patients participated in this study. All patients required localized alveolar ridge augmentation before placement of dental implants. An equal mixture of autogenous bone graft and inorganic bovine mineral (Bio-Oss) was used as a bone graft material. Autogenous bone graft was harvested intraorally. Titanium mesh was submerged for 8.47 months (SD 2.83). Impressions were taken intraorally before bone grafting, 6 months after bone grafting, and 6 months after implant placement. Impressions were used to measure the volume of alveolar ridge augmentation and provide linear laboratory measurements regarding the results of bone augmentation. Bone quality (type II-IV) was recorded during implant surgery. Standardized linear tomographs were taken before bone grafting and before implant placement. A biopsy was harvested with a trephine bur from the grafted area during implant surgery for histologic-histomorphometric evaluation. In all cases the grafted area had adequate bone volume and consistency for placement of dental implants. Early mesh exposure (2 weeks) was observed in 2 patients, and late exposure (>3 months) was observed in 4 patients. Volumetric laboratory measurements indicated 0.86 cc (SD 0.69) alveolar augmentation 1 month after bone grafting, 0.73 cc (SD 0.60) 6 months after bone grafting, and 0.71 cc (SD 0.57) 6 months after implant placement. This indicated 15.11% resorption 6 months after bone grafting, and no further resorption occurred after implant placement. Linear laboratory measurements indicated vertical augmentation of 2.94 mm (SD 0.86) 1 month after bone grafting, 2.59 mm (SD 0.91) 6 months after bone grafting, and 2.65 mm (SD 1.14) 6 months after implant placement. The corresponding measurements for labial-buccal augmentation were 4.47 mm (SD 1.55), 3.88 mm (SD 1.43), and 3.82 mm (SD 1.47). Radiographic evaluation indicated 2.56 mm (SD 1.32) vertical augmentation and 3.75 mm (SD 1.33) labial-buccal augmentation. Histomorphometric evaluation indicated 36.47% (SD 10.05) new bone formation, 49.18% (SD 6.92) connective tissue, and 14.35% (SD 5.85) residual Bio-Oss particles; 44.65% (SD 22.58) of the Bio-Oss surface was in tight contact with newly formed bone. The use of titanium mesh for localized alveolar ridge augmentation with a mixture of autogenous intraorally harvested bone graft and Bio-Oss offered adequate bone volume for placement of dental implants. Intraorally harvested autogenous bone graft mixed with Bio-Oss under a titanium mesh offered 36.47% new bone formation, and 15.11% resorption occurred 6 months after bone grafting.

Inferior Alveolar Nerve Transposing in a Situation with Minimal Bone Height: A Clinical Report

Previous studies have indicated that at least 5 mm of bone is needed above the canal when performing transposing of the inferior alveolar nerve (TIAN). In this clinical report, TIAN was performed in a situation where minimal (< 2 mm) bone height was present above the canal of the IAN. Preoperative examination with computerized tomography scan revealed 2 mm of bone above the canal at the area of teeth #18 to #20, #30, and #31. The TIAN was performed by opening a lateral access window along the lateral side of the mandible. Five threaded hydroxyapatite-coated root form implants were placed at the area of teeth #18 to #20, #30, and #31. Autogenous bone from the lateral access window that was removed en block was particulated and placed around the implants. A resorbable collagen membrane was placed around the graft material. Implants were restored with cement-retained implant-supported metal-ceramic crowns. Three-year post-loading examination revealed minimal bone loss (< 1 mm).