Andreas Stavropoulos

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft: a systematic review.

AIMS The objective of the present systematic review was to test the hypothesis of no differences in the implant treatment outcome when Bio-Oss or Bio-Oss mixed with autogenous bone is used as graft for the maxillary sinus floor augmentation (MSFA) applying the lateral window technique. MATERIAL AND METHODS A MEDLINE (PubMed) search in combination with a hand search of relevant journals was conducted by including human studies published in English from January 1, 1990 to June 1, 2010. The search provided 879 titles and 35 studies fulfilled the inclusion criteria. Considerable variation in the included studies prevented meta-analysis from being performed and no long-term study comparing MSFA with the two treatment modalities was identified. Also, the survival of suprastructures after the two augmentation procedures was not compared within the same study. RESULTS The 1-year implant survival was compared in one study demonstrating no statistically significant difference. The implant survival was 96% with Bio-Oss and 94% with a mixture of 80% Bio-Oss and 20% autogenous mandibular bone. Addition of a limited amount of autogenous bone to Bio-Oss seemed not to increase the amount of new bone formation and bone-to-implant contact compared with Bio-Oss. CONCLUSIONS Therefore, the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected.

Preclinical in vivo research in implant dentistry. Consensus of the eighth European workshop on periodontology.

UNLABELLED Guidelines for improving the reporting in preclinical in vivo research (ARRIVE) have been recently proposed. AIM The aim was to assess to what extent the ARRIVE guidelines were considered in preclinical in vivo studies in implant dentistry. MATERIAL AND METHODS Four comprehensive systematic reviews evaluated to what extent the ARRIVE guidelines were considered in preclinical in vivo studies in implant dentistry. Studies on the influence of implant material, surface and design on tissue integration to implants placed in pristine bone, in locally compromised sites and/or systemically compromised animals, as well as on peri-implant mucositis and peri-implantitis were evaluated. The four reviews introduced different modifications to the ARRIVE guidelines dedicated to the specific assignment of the review. RESULTS A large variation in the frequency of reporting with regard to the items of the modified ARRIVE guidelines was observed. The reviews revealed that relevant information, e.g. sample size calculation, blinding of the assessor etc., was often not reported. It was also identified that several items in the ARRIVE guidelines may be less--if at all--applicable to research in implant dentistry. CONCLUSION It is suggested that researchers implement, whenever relevant, the ARRIVE guidelines during planning and reporting of preclinical in vivo studies related to dental implants.

Guided tissue regeneration combined with a deproteinized bovine bone mineral (Bio‐Oss®) in the treatment of intrabony periodontal defects: 6‐year results from a randomized‐controlled clinical trial

AIM To present the 6-year results of a randomized-controlled clinical trial evaluating guided tissue regeneration (GTR) combined with or without deproteinized bovine bone mineral (DBBM) in intrabony defects. MATERIAL & METHODS In each of 45 patients, one defect was treated with GTR combined with DBBM hydrated in saline (DBBM-) or gentamicin sulphate (DBBM+) or with GTR alone. Clinical parameters were recorded pre-surgery, at 1 and 6 years postsurgery. RESULTS Thirty-six patients/33 teeth were available for the 6-year control. Statistically significant clinical improvements were observed for all treatments. Clinical attachment level (CAL) gain averaged 2.5 mm (DBBM-), 4.1 mm (DBBM+), and 3.0 mm (GTR) at 1 year postsurgery, and remained stable over 5 additional years (2.3, 4.1, and 2.7 mm, respectively). Treatment did not appear to influence residual probing depths (PDs) or CAL gains at 6 years postsurgery, or the extent of PD and CAL change from 1 to 6 years, and did not associate with sites losing CAL during follow-up. No association of grafting with sites showing CAL gain >or=4 mm at the 1- or 6-year control was observed. CONCLUSION The improvements in periodontal conditions obtained after GTR treatment with or without the adjunct use of DBBM can be preserved on a long-term basis.

Periodontal Regeneration: Focus on Growth and Differentiation Factors

Several growth and differentiation factors have shown potential as therapeutic agents to support periodontal wound healing/regeneration, although optimal dosage, release kinetics, and suitable delivery systems are still unknown. Experimental variables, including delivery systems, dose, and the common use of poorly characterized preclinical models, make it difficult to discern the genuine efficacy of each of these factors. Only a few growth and differentiation factors have reached clinical evaluation. It appears that well-defined discriminating preclinical models followed by well-designed clinical trials are needed to further investigate the true potential of these and other candidate factors. Thus, current research is focused on finding relevant growth and differentiation factors, optimal dosages, and the best approaches for delivery to develop clinically meaningful therapies in patient-centered settings.

Clinical and histologic evaluation of granular Beta-tricalcium phosphate for the treatment of human intrabony periodontal defects: a report on five cases.

BACKGROUND The aim of the study is to clinically and histologically evaluate the healing of advanced intrabony defects treated with open flap debridement and the adjunct implantation of granular beta tricalcium phosphate (beta-TCP). METHODS Five patients, each displaying advanced combined 1- and 2-wall intrabony defects around teeth scheduled for extraction or root resection, were recruited. Approximately 6 months after surgery, the teeth or roots were removed together with a portion of their surrounding soft and hard tissues and processed for histologic evaluation. RESULTS The mean probing depth (PD) was reduced from 10.8 +/- 2.3 mm presurgically to 4.6 +/- 2.1 mm, whereas a mean clinical attachment level (CAL) gain of 5.0 +/- 0.7 mm was observed. The increase in gingival recession was 1.2 +/- 3.2 mm. The histologic evaluation indicated the formation of new cellular cementum with inserting collagen fibers to a varying extent (mean: 1.9 +/- 0.7 mm; range: 1.2 to 3.03 mm) coronal to the most apical extent of the root instrumentation. The mean new bone formation was 1.0 +/- 0.7 mm (range: 0.0 to 1.9 mm). In most specimens, beta-TCP particles were embedded in the connective tissue, whereas the formation of a mineralized bone-like or cementum-like tissue around the particles was only occasionally observed. CONCLUSION The present data indicates that treatment of intrabony periodontal defects with this beta-TCP may result in substantial clinical improvements such as PD reduction and CAL gain, but this beta-TCP does not seem to enhance the regeneration of cementum, periodontal ligament, and bone.

Biomaterials for promoting periodontal regeneration in human intrabony defects : a systematic review

Intrabony periodontal defects are a frequent complication of periodontitis and, if left untreated, may negatively affect long-term tooth prognosis. The optimal outcome of treatment in intrabony defects is considered to be the absence of bleeding on probing, the presence of shallow pockets associated with periodontal regeneration (i.e. formation of new root cementum with functionally orientated inserting periodontal ligament fibers connected to new alveolar bone) and no soft-tissue recession. A plethora of different surgical techniques, often including implantation of various types of bone graft and/or bone substitutes, root surface demineralization, guided tissue regeneration, growth and differentiation factors, enamel matrix proteins or various combinations thereof, have been employed to achieve periodontal regeneration. Despite positive observations in animal models and successful outcomes reported for many of the available regenerative techniques and materials in patients, including histologic reports, robust information on the degree to which reported clinical improvements reflect true periodontal regeneration does not exist. Thus, the aim of this review was to summarize, in a systematic manner, the available histologic evidence on the effect of reconstructive periodontal surgery using various types of biomaterials to enhance periodontal wound healing/regeneration in human intrabony defects. In addition, the inherent problems associated with performing human histologic studies and in interpreting the results, as well as certain ethical considerations, are discussed. The results of the present systematic review indicate that periodontal regeneration in human intrabony defects can be achieved to a variable extent using a range of methods and materials. Periodontal regeneration has been observed following the use of a variety of bone grafts and substitutes, guided tissue regeneration, biological factors and combinations thereof. Combination approaches appear to provide the best outcomes, whilst implantation of alloplastic material alone demonstrated limited, to no, periodontal regeneration.

Growth and differentiation factors for periodontal regeneration: a review on factors with clinical testing

BACKGROUND AND OBJECTIVE A large body of evidence implies that growth and differentiation factors, based on their ability to regulate various functions of cells originating in the periodontal tissues, may support periodontal wound healing/regeneration, creating an environment conducive to and/or immediately inducing de novo tissue formation. This study presents a short systematic overview on growth and differentiation factor technologies evaluated in the clinic for their potential to enhance periodontal wound healing/regeneration. MATERIAL AND METHODS Reports on growth and differentiation factor technologies evaluated in the clinic for their potential to enhance periodontal wound healing/regeneration were selected for review. RESULTS Growth and differentiation factor technologies intended for periodontal wound healing/regeneration and evaluated clinically included platelet-derived growth factor, insulin-like growth factor-I and -II, basic fibroblast growth factor, bone morphogenetic protein-3 and growth differentiation factor-5; platelet-derived growth factor was the only Food and Drug Administration-approved commercially available growth and differentiation factor technology. In general, enhanced periodontal regeneration was observed in sites receiving growth and differentiation factors compared with control(s). However, improvements of relatively limited clinical magnitude have been shown thus far. CONCLUSION Although growth and differentiation factors project considerable appeal as candidate technologies in support of periodontal wound healing/regeneration, current candidate and commercially available technologies enhance treatment outcomes only to a limited extent in clinical settings.

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft in animals: a systematic review

The objective of the present systematic review was to test the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for maxillary sinus floor augmentation (MSFA) applying the lateral window technique, as evaluated in animals. A MEDLINE (PubMed), Embase, and Cochrane Library search in combination with a hand-search of relevant journals was conducted by including animal studies published in English from 1 January 1990 to 1 June 2010. The search provided 879 titles and 14 studies fulfilled the inclusion criteria. The volumetric stability of the graft improved significantly with increased proportion of Bio-Oss. Bone regeneration, bone-to-implant contact (BIC), biomechanical implant test values, and biodegradation of Bio-Oss after MSFA with Bio-Oss or Bio-Oss mixed with autogenous bone have never been compared within the same study in animals. Thus, the hypothesis of no differences between the use of Bio-Oss and Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected based on existing animal studies.

Graft incorporation and implant osseointegration following the use of autologous and fresh-frozen allogeneic block bone grafts for lateral ridge augmentation

OBJECTIVES To compare autogenous bone (AT) and fresh-frozen allogeneic bone (AL) in terms of histomorphometrical graft incorporation and implant osseointegration after grafting for lateral ridge augmentation in humans. MATERIALS AND METHODS Thirty-four patients were treated with either AL (20 patients) or AT (14 patients) onlay grafts. During implant installation surgery 6 months after grafting, cylindrical biopsies were harvested perpendicularly to the lateral aspect of the augmented alveolar ridge. Additionally, titanium mini-implants were installed in the grafted regions, also perpendicularly to the ridge; these were biopsied during second-stage surgery. Histological/histomorphometric analysis was performed using decalcified and non-decalcified sections. RESULTS Histological analysis revealed areas of necrotic bone (NcB) occasionally in contact with or completely engulfed by newly formed vital bone (VB) in both AT and AL groups (55.9 ± 27.6 vs. 43.1 ± 20.3, respectively; P = 0.19). Statistically significant larger amounts of VB (27.6 ± 17.5 vs. 8.4 ± 4.9, respectively; P = 0.0002) and less soft connective tissue (ST) (16.4 ± 15.6 vs. 48.4 ± 18.1, respectively; P ≤ 0.0001) were seen for AT compared with AL. No significant differences were observed between the groups regarding both bone-to-implant contact (BIC) and the bone area between implant threads (BA) on the mini-implant biopsies. CONCLUSION Allogeneic bone block grafts may be an option in cases where a limited amount of augmentation is needed, and the future implant can be expected confined within the inner aspect of the bone block. However, the clinical impact of the relatively poor graft incorporation on the long-term performance of oral implants placed in AL grafts remains obscure.

Volume changes of maxillary sinus augmentations over time: a systematic review.

PURPOSE The objective of this study was to systematically review the available literature on three-dimensional time-dependent graft volume changes after sinus augmentation (SA) with different biomaterials in humans. MATERIALS AND METHODS MEDLINE, EMBASE, and CENTRAL were searched for related literature. Controlled and uncontrolled studies reporting volume changes of more than 10 SAs after at least 6 months, assessed by computed tomography (CT) or cone beam CT (CBCT), were eligible for inclusion. The primary outcome of interest was time-dependent percentage change in augmentation volume. RESULTS Seven controlled and five uncontrolled studies (n = 234 SAs) with a high risk of bias were included and reported on a range of graft materials. Autogenous bone (AB) was used in the particulate or block form. Bone substitutes (BS) were used either alone or in combination with other materials as composite grafts (CG). All studies reported reductions in augmentation volumes over time (AVR), generally after short observation periods (range, 6 months to 6 years). Substantial AVRs (approximately 45% in 77 SAs) were reported for AB after 6 months and up to 2 years. AVRs for solely BS or CG were relatively lower (approximately 18% to 22% in 142 SAs) after a similar time period. All studies reported a wide range of volume reductions. No significant differences in AVR were observed between different graft materials. Because of insufficient long-term data, a reliable association between volume reduction and time could not be established. CONCLUSION Some loss of augmentation volume always occurs after SA during early healing times. In general, less AVR may be expected after SA with BS or CG compared to SA with AB. Augmentation volume loss does not seem to compromise implant placement or survival.