Statements and Recommendations for Guided Bone Regeneration: Consensus Report of the Guided Bone Regeneration Symposium Held in Bologna, October 15 to 16, 2016.

INTRODUCTION: In the past 10 years, long-term studies have demonstrated that guided bone regeneration (GBR) is a successful and reliable technique for vertical and horizontal ridge augmentation, but strict and rigorous protocols must be adopted. MATERIAL AND METHODS: Because no reports have yet been published with statements and clinical recommendations for GBR, a closed meeting of all authors was organized to discuss this matter during a GBR symposium held in Bologna (Italy) in October 2016. The authors focused on the findings of systematic and narrative reviews, prepared before the meeting, covering aspects of the clinical management of GBR techniques. Successively, a discussion based on the scientific evidence and on the experts' opinions led to the formulation of statements, clinical recommendations, and implications for future research. RESULTS: To avoid complications and to optimize outcomes, the following factors should be considered by clinicians: patient selection; analysis of defect type; blood supply; antibiotic treatment; flap passivation; delayed implant placement; combination of autogenous bone and xenograft or allograft; rigorous fixation of membranes; removal after 6 to 9 months; analysis of complications; soft-tissue management; and high care in scarred sites and in esthetic areas. CONCLUSIONS: The present consensus report reviewed the scientific evidence and provided specific guidelines and recommendations for clinical practice and the different approaches to GBR techniques to ensure surgical success and predictable outcomes.

Microradiography and microcomputed tomography comparative analysis in human bone cores harvested after maxillary sinus augmentation: a pilot study.

OBJECTIVES: The aim of this study was to compare microradiography (MR) and microcomputed tomography (µCT) analysis of bone samples following maxillary sinus augmentation at different time periods and determine the relationships between measured area and volume fractions. MATERIALS AND METHODS: Lateral window sinus grafts were performed on 10 patients using a mineralized human bone allograft (MHBA). At implant placement, 5-13 months after surgery, 10 bone core biopsies were harvested. Prior to histologic sectioning, bone samples were evaluated with µCT. The morphometric parameters computed by MR and µCT were compared using Pearson's correlation and Bland and Altman analysis and included hard tissue fraction (HV/TV:%), soft tissue fraction (SV/TV:%), vital bone fraction (BV/TV:%) and residual graft fraction (GV/TV:%). RESULTS: Strong positive correlation between MR and µCT was found for HV/TV and SV/TV and BV/TV [r = 0.84, 0.84 and 0.69, respectively] but weak for GV/TV [r = 0.10]. CONCLUSION: µCT technology shows promising potential as an indicator of bone morphology changes; however, caution should be used in interpreting morphometric parameters, as the different methods reveal important biases.

Maxillary Sinus Floor Augmentation with Porcine-Apatite Xenograft: A Prospective Case Series Study.

This study clinically and histologically evaluated the outcome of a porcineapatite xenograft used to elevate the maxillary sinus floor in a severely atrophic ridge. A two-stage crestal window sinus elevation protocol was conducted in 24 patients with crestal bone ≤ 2 mm. Highly porous porcine carbonate apatite moistened with saline solution was placed in the elevated sinus cavity as the sole grafting material. Bone core biopsy samples were taken at 6, 9, and 12 months after sinus augmentation surgery (at implant placement). Treatment outcomes were assessed using microCT (µCT) and histologic analysis. Statistical analysis was performed using nonparametric Kruskal-Wallis test, followed by post-hoc Dunn multiple comparison test. At 6 months after implant placement, all implants achieved good primary stability (insertion torque ≥ 30 Ncm) and successfully osseointegrated. The residual graft amount (mean ± SE) was low (11.91% ± 1.99%) at 6 months and further decreased (6.11% ± 2.64%) by 12 months. On the contrary, the amount of new bone detected was 18.94% ± 4.08% at 6 months and was significantly (P < .05) increased (40.16% ± 5.27%) at 12 months. Histologic assessment revealed osteoclasts actively resorbing the graft as well as osteoblasts actively forming new bone. In the severely atrophic maxilla, the porcine-apatite xenograft promotes new bone formation while being slowly absorbed. Within the limited sample size, the porcine-apatite xenograft seems to be a good graft material for crestal window sinus augmentation.

Cortical Versus Cancellous Solvent-Dehydrated Bone Allograft for Alveolar Ridge Preservation: A Histologic Study.

Allografts have been routinely used for immediate grafting of extraction sites as modalities of alveolar ridge preservation (ARP). Solvent-dehydrated bone allograft (SDBA), which is commonly utilized for socket grafting, exists in the form of cortical and cancellous particles. This study aims to provide a histologic comparison of cortical and cancellous SDBA for ARP. A total of 35 extraction sockets were allocated to receive either a cortical (17 sites) or cancellous (18 sites) SDBA, followed by application of a resorbable collagen wound dressing in both groups. At approximately 4 months, a bone core biopsy sample was obtained during implant placement. Histomorphometric assessment was then conducted to compare the differences between both forms of SDBA. Within its limitations, a higher percentage of vital bone was observed in the cortical bone group compared to the cancellous bone group (28.6% vs 20.1%, respectively, P = .042), while there was a lack of statistically significant differences among other fractions of the bone biopsy sample (residual graft particles and nonmineralized tissues such as connective tissue or other components).

Influence of apico-coronal positioning of tissue-level implants on marginal bone stability during supracrestal tissue height establishment: A multi-center prospective study.

INTRODUCTION: Supracrestal tissue height establishment is a crucial factor influencing peri-implant marginal bone modifications prior to prosthesis delivery. If mucosal thickness is insufficient, peri-implant marginal bone resorption occurs to allow appropriate supracrestal tissue height formation. This study evaluates if marginal bone resorption occurring around tissue-level implants before prosthetic loading could be compensated by adapting apico-coronal positioning to mucosal thickness. METHODS: Patients requiring placement of one single implant in the posterior mandible were treated with tissue-level implants with a 3-mm high transmucosal machined component and moderately rough implant body. Based upon vertical mucosal thickness measured after buccal flap reflection, implants were placed with the treated part: (group 1) 2 mm below crestal level in presence of thin mucosa (<2.5 mm); (group 2) 1 mm below the crestal level in presence of medium mucosa (2.5-3.5 mm); (group 3) at equicrestal level in presence of thick mucosa (>3.5 mm). RESULTS: Forty-nine implants, placed in 49 patients were included in final analysis (group 1: 18 implants; group 2: 16 implants; group 3: 15 implants). Mean marginal bone resorption after 5 months of healing was 0.66 ± 0.49 mm, 0.32 ± 0.41 mm, and 0.22 ± 0.52 mm in groups 1, 2, and 3, respectively. Inter-group analysis highlighted significant differences between the three groups after ANOVA test (p = 0.025). However, adaptation of apico-coronal implant positioning in relation to mucosal thickness, allowed to avoid early exposure of the treated surface in 100%, 93.7%, and 53.3% of the implants in groups 1, 2, and 3, respectively. CONCLUSION: During supracrestal tissue height formation, tissue-level implants inserted adapting apico-coronal positioning in relation to mucosal thickness exhibited greater marginal bone resorption at sites with thin mucosa than at sites with medium or thick mucosa. However, anticipating supracrestal tissue height establishment by adapting apico-coronal implant positioning in relation to mucosal thickness may effectively prevent unwanted exposure of treated implant surface.

Atrophic maxillary floor augmentation by mineralized human bone allograft in sinuses of different size: an histologic and histomorphometric analysis.

OBJECTIVE: The aims of this work were to histologically examine the healing of mineralized human bone allograft (MHBA) in sinus augmentation for elevating a severe maxillary atrophy ridge (≤2 mm residual ridge height) and to correlate the results to the sinus cavity size. MATERIAL AND METHODS: A two-stage protocol was conducted in 23 patients, all having crestal bone ≤2 mm. A mixture of 80/20 cortical/cancellous of MHBA particles was used to augment sinus using the lateral window approach in narrow (NS; <15 mm bucco-palatal distance) and wide (WS; ≥15 mm bucco-palatal distance) sinuses, based upon computerized tomography (CT) assessment. A bone core biopsy was taken at implant placement, 6 and 9 months after surgery. Microradiography, histology and histochemistry of methacrylate-embedded sections were performed to analyze and to evaluate the bone and graft amount. RESULTS: Newly formed bone around MBHA particles was found in all 28 biopsies. Bone showed a woven structure at 6 months after surgery and a lamellar structure 9 months after surgery. At 6 months after surgery, the 13 NS and 15 WS had 30.5±8.8% and 20.7±4.9% mean±SD bone formation, respectively. At 9 months after surgery, it was 38.8±7% (NS) and 30.7±3% (WS). Residual graft was about 16% (6 months) and 6% (9 months), in both NS and WS. The Mann-Whitney test showed a greater bone formation in NS than in WS (P<0.005). CONCLUSIONS: The used 80/20 MHBA mixture appears to promote, in the severe atrophic maxilla, a satisfactory bone formation. Our results prove that the larger the sinus, the longer the maturation time needed to achieve a suitable amount of new bone formation.

Crestal sinus lift with sequential drills and simultaneous implant placement in sites with <5 mm of native bone: a multicenter retrospective study.

PURPOSE: The aim of this multicenter retrospective clinical study was to evaluate the survival rate of implants placed in the posterior maxilla with a residual bone height of <5 mm. MATERIALS AND METHODS: One hundred seventeen patients, recruited from 6 different centers, had 134 implants placed below the maxillary sinus. The patient population consisted of 52 men and 65 women ranging in age from 39 to 78 years (mean age, 53.2 years). Sinus lift procedures were performed following a crestal approach using a specific sequence of drills (Cosci's technique). All implants were submerged. Periapical radiographs were obtained with a paralleling technique and were digitized. The pattern of bone remodeling was subsequently evaluated. RESULTS: The average (±SD) follow-up time was 48.2 months (±29.30 months; range, 24 to 120 months). Of the original 134 implants placed, 5 implants (3.7%) failed. The implant survival rate was 96.3%. The average residual bone height was 3.46 mm (±0.91 mm) at baseline. The average height of the alveolar crest in the treated implant sites was 9.94 ± 2.29 mm. The radiographic bone gain was 6.48 ± 2.38 mm. CONCLUSION: The investigation suggests that this crestal drill approach can be a successful sinus lifting procedure in a severe atrophic maxilla with <5 mm of crestal bone height.

A mandibular implant-supported fixed complete dental prosthesis in a patient with Sjogren syndrome: case report.

The article describes the treatment and 1 year follow-up of a patient with Sjogren syndrome, treated with 6 intraforaminal mandibular implants with delayed loading and an implant-retained fixed prosthesis. The maxillary arch has been treated with a complete denture. This made an enormous difference in comfort and function for the patient. Radiographic check-ups did not reveal any peri-implant bone loss after 1 year of loading.

Reliability of Cone Beam Computed Tomography in Determining Mineralized Tissue in Augmented Sinuses.

PURPOSE: The aim of this study was to analyze cone beam computed tomography (CBCT) densitometries of maxillary sinuses augmented with human bone allograft. In addition, previously obtained microradiographic specimens were used to verify the diagnostic potential of CBCT. MATERIALS AND METHODS: A two-stage protocol was conducted in 21 consecutive patients, all with a crestal bone height < 2 mm. Mineralized human bone allograft particles were used to augment sinuses using a lateral window approach. A succession of CBCT scans of the maxilla were taken before surgery, immediately after sinus augmentation, and 6, 10, and 18 months after implant placement. Using virtual probes, CBCT images taken at 6, 8, and 10 mm from the crestal surface were processed with medical imaging software and expressed as gray level (GL). RESULTS: A total of 24 sinus augmentation procedures were performed in 21 patients. The average values of CBCT-GL ranged from 571 to 654, presenting the maximum value at 8 mm immediately after implant placement and the minimum value at 6 mm after 10 months. Furthermore, it was found that the graft mineral content decreased over time, completely disappearing between 10 and 11 months. CONCLUSION: CBCT and the medical imaging software employed for imaging visualization are reliable tools to study biomaterial behavior after sinus augmentation procedures. In addition, results from this study demonstrate that a complete resorption of human bone allograft is possible. Due to the limited sample size, further clinical and morphometric studies are needed.

A retrospective study on a series of 556 zimmer dental implants.

BACKGROUND: One-stage surgery with immediate loading is possible, with good clinical results. Many types of dental implants are available in the market. Zimmer Dental Implants (ZDIs) have been used since the nineties, but few reports have analyzed the clinical outcome of these fixtures. We planned a retrospective study on a series 566 ZDIs, to evaluate their clinical outcome. MATERIALS AND METHODS: In the period between January 2007 and June 2011, 125 patients were treatetd with ZDIs. The last check-up was performed in June 2012, with a mean follow-up period of 17 ± 9 months (minimum - maximum, 8-4 months). ZDIs were inserted as follows: 295 (53.1%) in the maxilla and 261 (46.9%) in the mandible. There were 480 (86.3%) Screw-vents, 51 (9.2%) Swiss Plusses, and 25 (4.5%) Splines. Sixteen, 355, 34, 90, 55, and six fixtures had a diameter of 3.25, 3.7, 3.75, 4.1, 4.7, and 4.8 mm, respectively. Twenty-eight, 145, 5, 217, 8, 141, and 12 implants hade a length of 8, 10, 11, 11.5, 12, 13, and 14 mm, respectively. The implants were inserted to replace 136 (24.5%) incisors, 80 (14.4%) cuspids, 198 (35.6%) premolars, and 142 (25.5%) molars. RESULTS: No implants were lost (i.e., SRV = 100%). Among the studied variables, only those for the jaws were statistically significant, with a better outcome for implants inserted in the maxilla (P = 0.017). CONCLUSIONS: ZDIs are reliable devices to be used in implantology, althougth a higher marginal bone loss has to be expected when these implants are inserted in mandible.

Clinical and radiographic evaluation of immediately loaded one-piece implants placed into fresh extraction sockets.

OBJECTIVE: To assess clinical survival and success rates of one-piece implants placed at the time of tooth extraction with immediate provisionalization and to evaluate radiographic peri-implant bone loss around one-piece implants 1 year after functional loading. METHOD AND MATERIALS: Forty-six patients (20 men and 26 women) with a mean age of 45.5 years (range, 24 to 74 years) were recruited from four centers for this case series report. Immediately following the extraction of untreatable teeth, all patients received one-piece implants. The implants were immediately restored and placed into function with no occlusal contact. Outcome assessments included clinical and radiographic evaluations. RESULTS: Of the one-piece implants placed after extraction in the maxilla and mandible, 95.7% integrated successfully. The mean marginal bone loss after 1 year was 0.80 mm (SD, 0.53 mm). Overall peri-implant bone loss at maxillary sites was compared with overall bone loss at mandibular sites. At the 1-year follow-up, no statistically significant difference was found. The deeper the implants were placed below the crest, the more marginal bone loss was observed. However, no difference in marginal bone loss was observed as a consequence of the following three variables: implant length (10, 11.5, or 13 mm), implant diameter (3, 3.7, or 4.7 mm); and 3- and 6-month time periods after implant prosthesis placement. CONCLUSION: Based on data obtained from this sample size study, it can be concluded that one-piece implants can be successfully placed immediately after extraction with minimal peri-implant bone loss.