The International Journal of Oral & Maxillofacial Implants, 01/2016

Purpose: The aim of this study was to assess the efficacy of alveolar vertical distraction osteogenesis and autogenous bone grafting in terms of bone gain, bone resorption, and implant survival and success rates and investigate the relationship between bone gain and resorption after alveolar vertical distraction osteogenesis. Materials and Methods: A systematic search was done using MEDLINE, EMBASE, the Cochrane Library, and KoreaMed from inception to April 30, 2014. Supplementary manual searches of published full-text articles were also performed. Results: Searches of four electronic databases and manual searches resulted in 1,538 articles. After selection, four studies were included in the systematic review and meta-analysis. The difference in bone gain at the end of distraction or bone grafting was statistically significant (weighted mean difference [WMD] 1.86, 95% CI 0.03 to 3.69, P = .05; heterogeneity: I2 = 78%, P = .01). However, there was not a statistically significant difference between alveolar distraction osteogenesis and onlay bone grafting (WMD 0.30, 95% CI -0.99 to 1.59, P = .065). Bone resorption between the end of treatment and the time of implant placement was not statistically significant (WMD -0.12, 95% CI -1.10 to 0.85, P = .80; heterogeneity: I2 = 78%, P = .01). A simple equation related to bone gain and resorption after alveolar vertical distraction was induced from these results. Conclusion: There was not a statistically significant difference between alveolar distraction osteogenesis and onlay bone grafting in terms of bone gain and bone resorption. Schlagwörter: alveolar vertical distraction osteogenesis, autogenous bone graft, bone gain, bone resorption, meta-analysis

Purpose: This study aimed to test bacterial microleakage at the implant-abutment interface (IAI) before and after dynamic loading using a new chewing simulation. Materials and Methods: Fourteen implant systems (n = 5 samples of each) were divided into two groups: (1) systems with conical implant-abutment connections (IACs), and (2) systems with flat IACs. For collecting samples without abutment disconnection, channels (Ø = 0.3 mm) were drilled into implants perpendicularly to their axes, and stainless-steel cannulas were adhesively glued inside these channels to allow a sterilized rinsing solution to enter the implant interior and to exit with potential contaminants for testing. Implants were embedded in epoxy resin matrices, which were supported by titanium cylinders with lateral openings for inward and outward cannulas. Abutments were tightened and then provided with vertically adjustable, threaded titanium balls, which were cemented using composite cement. Specimens were immersed in a bacterial liquid and after a contact time of 15 minutes, the implant interior was rinsed prior to chewing simulation (0 N ⩠ static seal testing). Specimens were exposed to a Frankfurt chewing simulator. Two hundred twenty force cycles per power level (110 in ± X-axis) were applied to simulate a daily masticatory load of 660 chewing cycles (equivalent to 1,200,000 cycles/5 years). The applied load was gradually increased from 0 N to a maximum load of 200 N in 25-N increments. The implant interior was rinsed to obtain samples before each new power level. All samples were tested using fluorescence microscopy; invading microorganisms could be counted and evaluated. Results: No bacterial contamination was detected under static loading conditions in both groups. After loading, bacterial contamination was detected in one sample from one specimen in group 1 and in two samples from two specimens in group 2. Conclusion: Controlled dynamic loading applied in this study simulated a clinical situation and enabled time-dependent analysis regarding the bacterial seal of different implant systems. Conical IACs offer a better bacterial seal compared with flat IACs, which showed increased microleakage after dynamic loading. IAC design plays a crucial role in terms of bacterial colonization. Taking samples of the implant interior without abutment disconnection eliminates an error source. Schlagwörter: abutment disconnection, bacterial microleakage, chewing simulator, implant-abutment connection

Purpose: To evaluate the effectiveness of platelet-rich fibrin (PRF) and freeze-dried bone allograft (FDBA) in vertical bone augmentation with immediate implant placement using histologic analysis. Materials and Methods: Six Merino sheep received a total of 36 Brånemark MKIII implants; three implants were placed supracrestally in each tibia with vertical exposure of four threads. Each implant received one of the three grafting options (MinerOss + PRF or MinerOss or PRF). The grafting materials were covered with a resorbable collagen membrane (Mem-Lok 30 × 40 mm, BioHorizons). Animals were sacrificed at 4 and 8 weeks, respectively, and specimens were prepared and collected for histologic analysis. Ground sections and decalcified sections were prepared. Results: The various stages of graft integration into native bone and the implant were observed at different time points, and comparison between the three grafting options was possible. Osteogenic potential with vertical generation of bone was observed in the three groups. At week 4, woven bone formation at the bone graft interface was observed; new bone did not appear to be organized at week 4. At week 8, the graft appeared to be fully replaced by vital mature and wellorganized bone arranged in lamellae with osteocytes encapsulated within the bone. The vertical bone gain at 8 weeks was higher for the PRF + MinerOss group with viable bone extending above the first thread. Both the MinerOss and PRF groups had vertical bone gain extended to the second thread. Conclusion: MinerOss appeared to be effective in vertical bone augmentation with simultaneous implant placement. PRF enhanced vertical bone augmentation when combined with MinerOss. Schlagwörter: animal experiments, bone-implant interactions, bone regeneration, bone substitutes, growth factors, guided tissue regeneration

Purpose: Fractal analysis is a mathematical method used to describe the internal architecture of complex structures such as trabecular bone. Fractal analysis of panoramic radiographs of implant recipient sites could help to predict the quality of the bone prior to implant placement. This study investigated the correlations between the fractal dimension values obtained from panoramic radiographs and the insertion torque and resonance frequency values of mandibular implants. Materials and Methods: Thirty patients who received a total of 55 implants of the same brand, diameter, and length in the mandibular premolar and molar regions were included in the study. The same surgical procedures were applied to each patient, and the insertion torque and resonance frequency values were recorded for each implant at the time of placement. The radiographic fractal dimensions of the alveolar bone in the implant recipient area were calculated from preoperative panoramic radiographs using a box-counting algorithm. The insertion torque and resonance frequency values were compared with the fractal dimension values using the Spearman test. Results: All implants were successful, and none were lost during the follow-up period. Linear correlations were observed between the fractal dimension and resonance frequency, between the fractal dimension and insertion torque, and between resonance frequency and insertion torque. Conclusion: These results suggest that the noninvasive measurement of the fractal dimension from panoramic radiographs might help to predict the bone quality, and thus the primary stability of dental implants, before implant surgery. Schlagwörter: box-counting algorithm, dental implants, fractals, insertion torque, resonance frequency, trabecular bone

Purpose: Different treatment protocols in terms of number, diameter, and suprastructure design have been proposed for immediately loaded implants that are used to support mandibular overdentures opposed by maxillary conventional dentures. The aim of this study was to investigate the influence of these protocols on survival rates as well as clinical and prosthodontic outcomes. Materials and Methods: Several electronic databases were searched for all relevant articles published from 1966 to June 2014. Only randomized controlled trials and prospective studies with a minimum follow-up of 12 months were selected. The primary outcomes of interest were the success and survival rates of the implants. Prosthodontic complications were also evaluated. Results: Fourteen studies fulfilled the inclusion criteria. Of the studies identified, nine were randomized controlled trials and five were prospective studies. The mean follow-up period was 3 years or less for the vast majority of the studies. The reported survival and success rates were comparable to that of conventional loading for most of the included studies. No specific immediate loading protocol seemed to perform better in terms of clinical and prosthodontic outcomes. Conclusion: Immediate loading protocols of mandibular overdentures seem to be a viable alternative to conventional loading. It was not possible to recommend a specific treatment protocol related to the number, diameter of the implants, and attachment system used. Long-term, well-designed studies comparing different immediate loading modalities could help to establish a protocol that delivers the most clinically predictable, efficient, and cost-effective outcome for edentulous patients in need of implant overdentures. Schlagwörter: dental implants, implant supported/retained overdentures, immediate loading, mandible, systematic review

Purpose: The aim of this study was to evaluate whether photofunctionalization of titanium mesh enhances its osteoconductive capability. Materials and Methods: The titanium mesh (0.2 mm thickness) used in this study was made of commercially pure grade-2 titanium and had hexagonal apertures (2 mm width). Photofunctionalization was performed by treating titanium mesh with UV light for 12 minutes using a photo device immediately before use. Untreated or photofunctionalized titanium mesh was placed into rat femurs, and bone generation around titanium mesh was profiled using three-dimensional (3D) microcomputed tomography (micro-CT). A set of in vitro experiments was conducted using bone marrow-derived osteoblasts. Results: Photofunctionalized titanium mesh surfaces were characterized by the regenerated hydrophilicity and significantly reduced surface carbon. Bone generation profiling at week 3 of healing showed that the hexagonal apertures in photofunctionalized mesh were 95% filled, but they were only 57% filled in untreated mesh, particularly with the center zone remaining as a gap. Bone profiling in slices parallel to the titanium surface showed that photofunctionalized titanium mesh achieved 90% bone occupancy 0 to 400 μm from the surface, compared with only 35% for untreated mesh. Bone occupancy remained as high as 55% 800 to 1,200 μm from photofunctionalized titanium mesh surfaces, compared with less than 20% for untreated mesh. In vitro, photofunctionalized titanium mesh expedited and enhanced attachment and spread of osteoblasts, and increased ALP activity and the rate of mineralization. Conclusion: This study may provide novel and advanced metrics describing the osteoconductive property of photofunctionalized titanium mesh. Specifically, photofunctionalization not only increased the breadth, but also the 3D range, of osteoconductivity of titanium mesh, enabling space-filling and far-reaching osteoconductivity. Further translational and clinical studies are warranted to establish photofunctionalized titanium mesh as a novel clinical tool for better bone regeneration and augmentation. Schlagwörter: bone augmentation, guided bone generation (GBR), hydrophilicity, implants, osseointegration, ultraviolet (UV) light

Purpose: To evaluate changes in sinus dimensions immediately postoperatively and 1 year later using a composite of bovine-derived xenograft and autogenous bone for lateral bone augmentation of the maxillary sinus. Materials and Methods: Patients who underwent lateral wall sinus augmentation procedures without concomitant implant placement were considered for this retrospective analysis if they had three consecutive panoramic radiographs: pretreatment (T0), immediately after lateral wall sinus augmentation (T1), and approximately 1 year postoperatively (T2). Eighteen subjects aged 47 to 69 years were included. The surgical protocol included grafting with a composite of bovine-derived xenograft and autogenous bone (9:1 ratio). Digital panoramic radiographs were transferred into measurement software, and the following measurements were performed: (1) vertical distance from the alveolar crest to the height of the augmented material, (2) sagittal area of the grafted area, and (3) vertical distance from the alveolar crest to the roof of the maxillary sinus. All measurements were performed by one examiner. Double measurements were performed in nine patients at T2, and the calculated Cronbach's alpha statistic was very high (.9658 to .9882). Results: The mean overall sinus sagittal area was 1,330 ± 481 mm2 prior to the grafting procedure, when it decreased to 858.2 ± 436 mm2 (range, 380.7 to 2,134 mm2) immediately postoperatively (P = .0035) and remained stable at 1 year (mean, 882.2 ± 384 mm2, P > .05). Similarly, the overall area of the grafted material at the time of surgery was 468.3 ± 208 mm2 and was only slightly reduced at 1 year (422.2 ± 193 mm2). The midsagittal graft height at T1 (mean, 20.67 ± 4.5 mm) was insignificantly and minimally reduced at 1 year (mean, 19.35 ± 4.9 mm). Conclusion: The linear dimensions of composite bone-derived xenograft/autogenous bone grafts following lateral wall sinus augmentation exhibited minimal changes during the 8- to 12-month healing period. Schlagwörter: autogenous, lateral wall, radiographic measurements, sinus augmentation, xenograft

Purpose: To investigate the clinical usefulness, a customized abutment produced with the Pd-Ag-In alloy was compared with a customized abutment produced with the conventional titanium alloy for discoloration and mechanical accuracy. Materials and Methods: Discoloration and resistance to corrosion of the Pd-Ag-In alloy were evaluated using chemical solutions. Marginal adaptation of internal-type implants and abutments was compared using 10 titanium abutments and 10 Pd-Ag-In abutments using a surface measuring system. A detorque test was performed on 12 implant-abutment complexes of each control and experimental group to investigate screw joint stability. Cyclic loading simulating a human's mastication movement for 1 year was applied after 30 Ncm initial tightening, and the removal torque was measured using a digital torque gauge. The noninferiority test was conducted to compare the Pd-Ag-In alloy with a titanium abutment with a 10% margin. Results: The Pd-Ag-In alloy had a warm yellow color and displayed stable resistance to discoloration and corrosion, resulting in an advantageous esthetic property. When compared to the titanium alloy, it did not show noninferiority with respect to the gap between the implant and the abutment; the gap was approximately 13.3 μm on average, which was not significantly different from those observed in previous studies. After long-term use, it displayed statistically significant noninferiority in the removal torque value compared to the titanium group. Conclusion: The Pd-Ag-In alloy-based customized abutment had good mechanical properties of the implant-abutment complex as well as a superior esthetic property, and can provide favorable outcomes in anterior implant restoration. Schlagwörter: customized abutment, cyclic loading, dental implants, detorque value, implant-abutment gap

Purpose: To evaluate the biomechanical behaviors of multiple implant-supported prostheses with different implant lengths, connections, locations, and restoration materials in the maxillary anterior region using threedimensional finite element analysis. Materials and Methods: A finite element model of a maxillary image was created from a tomography data bank. The simulations were executed in two types of models based on the treatment plan: (1) two implants with 4.0-mm diameters placed in the maxillary central incisors to simulate an implant-supported fixed prosthesis with four elements with a cantilever of both maxillary lateral incisors; (2) two implants with 3.75-mm diameters placed in the maxillary lateral incisors to simulate a conventional fixed prosthesis with four elements with pontics for maxillary central incisors. Subsequently, the models created were subdivided into eight subgroups according to implant length, connection type, and restoration material. A total static oblique load of 150 N was applied to the cingulum area of the palatal surfaces of the four incisors at an angle of 45 degrees to the long axis of the implant in the palatal-labial direction. Bone stresses were analyzed through maximum and minimum principal stresses and ductile material as implant, framework, and abutments were analyzed using von Mises stress criterion. Results: Regardless of implant diameter and type of treatment, the 8.5-mm-long implants exhibited the lowest tensile and compressive stresses. Maximum and minimum principal stresses were identified in the cortical bone. The lowest von Mises equivalent stress values were identified in the metal-ceramic prostheses, with the exception of the cantilever prosthesis model with flat top connection. Conical cone implant models exhibited maximum von Mises equivalent stress in contact with the abutment. Conclusion: The lowest principal stresses in the periimplant bone were observed in implants with conical cone connection and 8.5 mm in length. Also, in most cases, the models with metal-ceramic restorations exhibited better stress distributions. Schlagwörter: biomechanics, dental implants, esthetic region, finite element analysis, stress distribution

Purpose: To verify whether the diversity of systemic medical conditions and smoking act as biologic associated factors for peri-implantitis. Materials and Methods: The PICO question was: "In patients with osseointegrated dental implants, does the presence of smoking habits or a compromised medical status influence the occurrence of peri-implantitis compared with the presence of good general health?" Smoking and systemic conditions such as type 2 diabetes mellitus, cardiovascular diseases, rheumatoid arthritis, lung diseases, obesity, cancer, deep depression, and osteoporosis were screened. Selection criteria included at least 10 patients per condition, 1 year of follow-up after implant loading, and strict cutoff levels (probing pocket depth [PPD], bleeding on probing [BOP] and/or pus, marginal bone loss) to define peri-implantitis. Results: From the 1,136 records initially retrieved, 57 were selected after title and abstract analyses. However, only six papers were considered for qualitative evaluation. No randomized controlled clinical trial was found. Smoking was associated with peri-implantitis in only one out of four studies. Poorly controlled type 2 diabetes accentuated only PPD and radiographic marginal bone level prevalence rates in peri-implant patients (one study). Cardiovascular disease was considered a risk (one out of two studies). The chance of peri-implant patients harboring the Epstein-Barr virus was threefold in one report. No associations were found for rheumatoid arthritis. Conclusion: Data from existing studies point to smoking and diabetes as biologic associated factors for peri-implantitis. However, the body of evidence is still immature, and the specific contribution of general health problems to peri-implantitis requires additional robust epidemiologic and clinical investigations. Schlagwörter: biologic factors, dental implants, peri-implantitis, systemic diseases

Purpose: The aim of this systematic review and meta-analysis was to evaluate crestal bone changes around implants when placing the implant-abutment connection at the crestal bone level or above. Materials and Methods: Medline (Pubmed), EMBASE, and Cochrane Library up to January 2014 were electronically and hand searched for any publications that evaluated radiographic crestal bone changes around nonsubmerged, rough-surfaced implants placed in healed sites in humans and loaded for a minimum of 1 year. Results: The search yielded 1,122 publications; 1,106 could not be included. After 16 full-text articles were read and subjected to inclusion and exclusion criteria, four were included. The mean difference was -0.29 mm (95% CI, -0.58 mm to -0.01 mm). Heterogeneity between studies was observed (I² = 95%). Significantly more crestal bone change was seen in the epicrestal implant-abutment (bone level) connection group when compared to implants with the prosthetic connection above the crestal bone level (tissue level) (P .00001). Conclusion: Dental implants at bone level show significantly less crestal bone change after 1 year of loading than tissue-level implants. Schlagwörter: alveolar bone loss, bone remodeling, dental implants

Purpose: Research waste occurs when research is ignored, cannot be found, cannot be used, or is unintentionally repeated. This article aims to investigate how dental survival analyses were indexed and reported, and to discuss whether errors in indexing and writing articles are affecting identification and use of survival articles, contributing to research waste. Materials and Methods: Articles reporting survival of dental prostheses in humans (also known as time-to-event) were identified by searching 50 dental journals that had the highest Impact Factor in 2008. These journals were hand searched twice (Kappa 0.92), and the articles were assessed by two independent reviewers (Kappa 0.86) to identify dental survival articles ("case" articles, n = 95), likely false positives (active controls, n = 91), and all other true negative articles (passive controls, n = 6,769). This means that the study used a case:control method. Once identified, the different groups of articles were assessed and compared. Allocation of medical subject headings (MeSH) by MEDLINE indexers that related to survival was sought, use of words by authors in the abstract and title that related to survival was identified, and use of words and figures by authors that related to survival in the articles themselves was also sought. Differences were assessed with chi-square and Fisher's Exact statistics. Reporting quality was also assessed. The results were reviewed to discuss their potential impact on research waste. Results: Allocation of survival-related MeSH index terms across the three article groups was inconsistent and inaccurate. Statistical MeSH had not been allocated to 30% of the dental survival "case" articles and had been incorrectly allocated to 15% of active controls. Additionally, information reported by authors in titles and abstracts varied, with only two-thirds of survival "case" articles mentioning survival "statistics" in the abstract. In the articles themselves, time-to-event statistical methods, survival curves, and life tables were poorly reported or constructed. Overall, the low quality of indexing by indexers and reporting by authors means that these articles will not be readily identifiable through electronic searches, and, even if they are found, the poor reporting quality makes it unnecessarily difficult for readers to understand and use them. Conclusion: There are substantial problems with the reporting of time-to-event analyses in the dental literature. These problems will adversely impact how these articles can be found and used, thereby contributing to research waste. Changes are needed in the way that authors report these studies and the way indexers classify them. Schlagwörter: information storage and retrieval, medical subject headings, quality of reporting, research waste, survival analyses

Purpose: To compare the 3-year outcome of dental implants placed simultaneously or delayed with intraoral onlay block bone grafts. Materials and Methods: A retrospective study was conducted of patients subjected to localized lateral alveolar ridge augmentation with intraoral onlay autogenous block bone grafts before or at implant placement between 2005 and 2010 in the Oral Surgery Unit of the University of Valencia (Valencia, Spain). The parameters evaluated at follow-up visits were implant survival and success rates, peri-implant soft tissue conditions (Plaque Index and Bleeding Index, probing depth, width of keratinized mucosa, and facial mucosal retraction), radiographic peri-implant marginal bone loss, and patient satisfaction. Results: Thirtyfour patients with 53 implants (23 delayed and 30 simultaneous) were included. After 3 years of loading, the cumulative implant success rate was 83.3% for simultaneous and 96.9% for delayed implants (P = .217). Average marginal bone loss was 1.15 ± 1.67 mm for simultaneously inserted implants and 0.29 ± 0.35 mm for delayed implants (P .01). There were no significant differences in Plaque Index or modified Bleeding Index between the groups. Peri-implant facial mucosal recession was more frequent in the simultaneous implant group (26.6% vs 13%), though the difference was not statistically significant. General patient satisfaction averaged 9.05 ± 0.82, and good quality of life was reported by all patients. Conclusion: Despite its sample size and design limitations, the delayed procedure showed less marginal bone loss and a lower prevalence of facial mucosal recession than the simultaneous implant placement procedure at 3 years postloading. Schlagwörter: alveolar ridge augmentation, bone grafting, dental implants

Purpose: To report the up-to-2-year outcomes of the immediately loaded novel variable-thread tapered implant with an internal conical connection and built-in platform shifting. Materials and Methods: Sixtyfour partially and completely edentulous patients were referred to two private centers for implant treatments between December 2010 and June 2012. Clinical and radiographic parameters were assessed retrospectively; the outcomes were implant and prosthetic failure, marginal bone remodeling, and complications. Results: One hundred forty-eight NobelReplace Conical Connection implants were placed in both postextraction sockets (n = 67) and healed sites (n = 81). One maxillary postextractive implant failed before the definitive prosthesis delivery, accounting for a cumulative success rate of 99.3%. No definitive prostheses failed. A mean marginal bone loss (MBL) of 0.42 ± 1.16 mm and 0.71 ± 1.53 mm was observed between implant placement and the 1-year (n = 147) and 2-year (n = 74) follow-up periods, respectively. In the postextraction sites, the mean MBL was 0.28 ± 0.39 mm and 0.69 ± 0.75 mm at the 1-year (n = 66) and 2-year (n = 50) follow-up periods; in the healed sites, the mean MBL was 0.51 ± 0.88 mm (n = 81) and 0.62 ± 0.80 mm (n = 24), respectively. At the 2-year follow-up session (n = 74), bleeding on probing was 8.3%, and the plaque score was 15.7%. No technical complications were observed. One biologic complication (0.8%) was reported. Conclusion: Within the limitations of this study and the relatively short follow-up, the immediately loaded NobelReplace Conical Connection implants demonstrated good treatment outcomes with regard to implant and prosthetic survival rate, MBL, and soft tissue conditions, in both postextraction and healed sites. Schlagwörter: conical connection, dental implant, immediate loading, platform switching, postextraction

Purpose: To report the 5-year outcome of NobelSpeedy design implants in immediate function fixed prosthetic rehabilitations. Materials and Methods: This retrospective clinical study included 46 consecutive patients (29 women and 17 men) with an average age of 55 years (range, 32 to 78 years) who were rehabilitated between 2003 and 2004 with full-arch restorations supported by dental implants in immediate function. The primary outcome measures were implant survival calculated based on implant function and using life tables. The secondary outcome measures were marginal bone levels measured at 3 and 5 years, and the incidence of mechanical and biologic complications. Results: Five patients with 21 study implants dropped out (11%). One-hundred eighty-nine implants were inserted in the maxilla (n = 166) and mandible (n = 23). Five patients lost five implants, giving a cumulative survival rate of 97.3% at 5 years of followup. The average (SD) marginal bone levels were 1.45 mm (0.83 mm) and 1.72 mm (1.04 mm) at 5 years of follow-up. The incidence of mechanical complications in the provisional and definitive prostheses was registered in 14 and 6 patients, respectively: prosthetic screw loosening (n = 4 provisional prostheses, n = 3 definitive prostheses), abutment screw loosening (n = 5 provisional prostheses), fracture of the acrylic resin prostheses (n = 5 provisional prostheses, n = 1 definitive prosthesis), chipping of a ceramic crown (n = 1 definitive prosthesis), and fracture of a ceramic crown (n = 1 definitive prosthesis). The incidence of biologic complications (peri-implant pathology) was registered in 6 patients and 12 implants (7.1%). Conclusion: Within the limitations of this study, it is possible to conclude that implants of the NobelSpeedy type used in immediate function for support of fixed prosthetic full-arch rehabilitations are a valid option, with a high survival rate. Schlagwörter: complications, dental implant, design, NobelSpeedy, oxidized, surface, survival, titanium

Purpose: The aim of this case series study was to evaluate clinical and radiographic changes of soft and hard tissues around tapered, platform-switched, laser-microtextured implants 24 months after crown placement. Materials and Methods: Twenty tapered, platform-switched, laser-microtextured collar implants were placed in 20 patients. Full-mouth plaque score, full-mouth bleeding score, probing depth, and mucosal recession were recorded at the time of crown cementation and after 24 months follow-up. The marginal bone-level changes at the mesial and distal aspects of the implants were calculated by subtracting from baseline and 24-month implant marginal bone level. Results: In terms of the full-mouth plaque score and full-mouth bleeding score, tapered, platformswitched, laser-microtextured implants showed statistically significant improvements at 6 months when compared to baseline (P .001). Statistically significantly deeper probing depths (P .001) were found when comparing baseline and at 24 months at mesial, lingual, and distal sites. However, no statistically significant difference was found at the buccal aspects (P = .064). Radiographic marginal bone loss at 2-year follow-up for tapered, platformswitched, laser-microtextured implants was 0.72 ± 0.16 mm and 0.67 ± 0.15 mm at the mesial and distal sites, respectively. Conclusion: Within the limits of this study, tapered, platform-switched, laser-microtextured implants maintained marginal bone level (less than 1 mm radiographic bone loss) as well as limited mucosa recession over a 2-year period. Schlagwörter: bone loss, dental implant, implant marginal, implant surface, laser-microtexture, platform switch

Purpose: This prospective, longitudinal study evaluated the survival, marginal bone levels, and soft tissue conditions for immediately loaded, straight-walled, platform-switched, titanium-alloy implants with an internal connection and nanosurface topography. Materials and Methods: Patients were enrolled at a single center. The immediate loading protocol required a final insertion torque ≥ 25 Ncm, an implant stability quotient (ISQ) > 55, and placement of the provisional prosthesis on the same day as implant placement. Posttreatment follow-up examinations were scheduled at 3, 6, and 12 months and annually thereafter. Soft tissue evaluation consisted of assessment of the implant sites for signs of peri-implant infection including mucosal inflammation, bleeding on probing or suppuration, and progressive bone loss. Oral hygiene was evaluated, and radiographic marginal bone levels were analyzed and compared to baseline at the time of provisional loading. Results: Forty-eight consecutively treated patients received 122 implants; 112 qualified for immediate loading and were included. ISQ scores ranged from 51 to 87, with a mean value of 75.1 (SD = 6.8). One implant failed (after 3 months). After an average follow-up period of 6.2 years (SD = 0.37; range, 5.4 to 6.9), no further losses occurred, leading to an overall cumulative survival rate of 99.1%. Average bone loss for the 111 implants after 6 years was 0.35 mm (SD = 0.45; range: -0.35 to 2.20). Four implants (3.6%) in two patients showed concomitant peri-implant infections associated with bleeding on probing and/ or purulence after 2 years in function. Exploratory surgery revealed residual submucosal cement. After its removal, the progressive bone loss stopped, and peri-implant tissue in both patients returned to a healthy condition. Conclusion: This study based on 40 patients treated with 112 straight-walled, platform-switched, titanium-alloy implants with nanosurface topography yielded a 99.1% survival rate after a mean followup time of 6.2 years. Additionally, mean crestal bone loss was limited to 0.26 mm (SD = 0.38) after 1 year and 0.35 mm (SD = 0.45) after 6 years. Peri-implant infection associated with excessive bone loss above 2 mm was only encountered in one implant, and residual cement was shown to be responsible. Schlagwörter: bone volume, dental implants, immediate loading, NanoTite, peri-implantitis, platform switching

Purpose: The aim of this noninterventional, retrospective case series was to evaluate the outcome of immediately loaded implants in patients with failing dentitions that require bone tabling using a bone reduction guide and a surgical guide manufactured directly on three-dimensional (3D) stereolithographic models. Materials and Methods: Consecutive patients with failing dentition and at least two remaining teeth who were treated in a single center between December 14, 2009 and September 23, 2013 were eligible. All patients receiving implants loaded with a hybrid prosthesis on the same day as extraction with their surgery planned on 3D models and performed using a surgical guide manufactured in a laboratory on the planning model were included. Patients who had undergone bone grafting procedures were excluded. Descriptive statistical analyses of available data were performed, including life-table calculations to derive a cumulative survival rate (CSR). Results: Two hundred twenty-eight patients (105 females and 123 males) received 1,657 implants (NobelActive) in 321 arches, in most cases 5 implants (range, 5 to 7) per arch. Ten preexisting implants were used. The mean insertion torque was 60.02 ± 13.1 Ncm (range, 15 to 75 Ncm). The definitive abutment was placed on the same day as surgery in all cases, and the definitive prosthesis (n = 304) was delivered after a mean of 7.9 ± 2.6 months. All implants were followed for 20.01 ± 11.3 months (range, 0 to 52 months) from implant insertion. Four implants (3 patients) had delayed loading, and one implant was left as a sleeping implant. Eight implants among six patients failed, two of the implants after prosthesis delivery. The CSR of the placed implants was 99.4% at implant level and 96.2% at patient level. Conclusion: Planning on 3D models to remove bone and place implants using custom-made bone reduction and surgical guides with immediate loading on the same day as extraction of remaining teeth was safe and effective for implant survival and rehabilitation of patients with periodontitis and failing dentition. Schlagwörter: bone reduction guide, dental implant, extraction sockets, immediate loading, surgical guide

Purpose: Reduction of alveolar height and width after tooth extraction may present problems for implant placement, since bone volume is important for biologic and esthetic reasons. The aim of this study was to assess bone healing of large bone defects grafted with collagen sheets and maintenance of reactive soft tissue, evaluating cone beam computed tomography (CBCT) scans and histomorphometric results. Materials and Methods: Patients presented large bone defects after tooth extractions. Reactive soft tissue was left in the defects filled by collagen sheets. Vertical bone volume was assessed by CBCT examinations before tooth extractions and 3 months later. At 3 months, cylinder bone samples were obtained for histology and histomorphometry analysis. Results: Twenty-six patients were included in the clinical study. Examined defects reported mean bone gain of 12.13 ± 3.91 mm, and mean vertical bone levels showed a statistically significant increase (P .05) at 3 months after extraction. Histologic examinations revealed bone formation; mean vital bone measurements were 41.59% ± 5.80%, and connective tissue percentages averaged 50.37% ± 7.73%. Conclusion: Reactive soft tissue left in large bone defects after tooth extraction and grafted collagen may support a significant vertical bone gain and vital bone formation. Schlagwörter: bone defects, collagen, cone beam computed tomography, reactive soft tissue

Purpose: The objective of this randomized controlled clinical split-mouth trial was to compare anodized implant surfaces and implant surfaces modified by acid etching in terms of primary and secondary stability. Materials and Methods: Forty-six implants were placed bilaterally in the posterior mandibles of 23 patients. Each patient received one implant with a surface treated by acid (AC) and the other with an anodized implant surface (ANO). The selection of the side where the implant was placed was chosen randomly by lot. The implants were evaluated with respect to insertion torque within the surgical bed and primary and secondary stability by testing the implant stability quotient (ISQ) at five different times (immediate postoperative period and 21, 30, 60, and 180 days after surgery). The paired t test was used to compare the two groups, and ANOVA Repeated Measures complemented by the Tukey posttest were used for longitudinal analysis of the implants in each group. All tests were applied with a confidence level of 95% (P .05). Results: No statistically significant difference was detected between the AC and ANO groups regarding insertion torque. ISQ analysis revealed that the AC group showed statistically higher values than the ANO group at the 21-day period (P .05); however, no other statistically significant differences were detected at the other times. Conclusion: The different surfaces were similar in terms of primary and secondary stability of implants placed in the posterior mandible. Schlagwörter: implant surface, osseointegration, stability

Impacted maxillary canine teeth commonly occur in the general population. The traditional therapeutic approach comprises fenestration and orthodontic traction; however, if traction is not feasible or the patient refuses orthodontic treatment, an alternative solution is to remove the impacted tooth and immediately place an implant. This technical note describes a novel surgical approach to rehabilitation after impacted canine tooth removal, entailing immediate placement of a long implant in combination with regenerative materials and a barrier. Of note, this procedure preserves the apical ridge bone crest, allowing implant anchorage and primary stability to be achieved. Schlagwörter: immediate dental implants, impacted tooth, oral surgery

Purpose: To assess bone regeneration potential of a fibronectin- and adipose-derived stem cell-covered ceramic biomaterial in three-wall critical-size alveolar ridge defects. Materials and Methods: In 18 dogs, four dehiscencetype and critical-size defects were created surgically in the edentulous alveolar ridge. Defects were randomly regenerated using biomaterials coated with particulate ß-tricalcium phosphate (ß-TCP), ß-TCP with fibronectin (Fn) (ß-TCP-Fn), and ß-TCP with a combination of Fn and autologous adipose-derived stem cells (ADSCs) (ß-TCP-Fn-ADSCs), leaving one defect as control. The animals were divided into three groups according to the time of euthanasia (1, 2, or 3 months of healing). Results: At the time of sacrifice, statistically significant differences between the four types of defects in the total area of bone regeneration, percentage of neoformed bone matrix, medullary space, or contact between particulate biomaterial and neoformed bone matrix were not found. All defects showed a significant increase in neoformed bone matrix as sacrifice was delayed, but a uniform pattern was not followed. Only defects treated with ß-TCP-Fn-ADSCs showed a significant increase in the bone regeneration area when animals sacrificed at 3 months were compared to those sacrificed at 1 month (P = .006). Conclusion: The use of ADSCs in bone regeneration processes of critical-size defects of the alveolar ridge did not entail an advantage regarding greater bone regeneration as compared with other biomaterials. However, the use of ß-TCP coated with a combination of Fn and ADSCs appeared to favor stabilization of the regenerated area, allowing a more efficient maintenance of the space at 3 months of healing. Schlagwörter: adipose-derived stem cells, dehiscence-type defect, fibronectin, guided bone regeneration, stem cells

Purpose: To compare the effects of different cell inoculation strategies on cellular attachment and viability as well as on osteogenic differentiation capacity and subsequent bone graft functionality after implantation of cellularized scaffolds in a mandibular defect rabbit model. Materials and Methods: Bone marrow stromal cells (BMSCs) were inoculated into the scaffolds of beta-tricalcium phosphate/chitosan (β-TCP/CS) either once or multiple times and their efficiency assessed based on cell viability, initial seeding efficiency, alkaline phosphatase activity in cell lysates, mineralization activity in cryosections of cell-seeded scaffolds by von Kossa staining, and osteogenic differentiation on reverse transcriptase polymerase chain reaction. Results: Compared with one-time inoculation of BMSCs, multiple inoculations led to higher cell viability, increased proliferation, more homogeneous distribution in the scaffold, better in vitro osteogenic differentiation, and improved in vivo bone repair in a rabbit model of mandibular defect. Conclusion: Multiple inoculations have many advantages over the one-time inoculation method and should be further researched for bone tissue engineering. Schlagwörter: bone marrow stromal cells, inoculation, seed cells

Purpose: To evaluate the regenerative results of the addition of bone marrow aspirate concentrate, using a single or double centrifugation protocol, to a xenogeneic bone graft in sinus floor elevation. Materials and Methods: Using a randomized, controlled pilot study design in 15 consecutive patients, sinus floor elevation procedures were performed with a xenogenous bone graft alone (control group, CG) or associated with bone marrow aspirate concentrate obtained by single centrifugation (single centrifugation group, SCG) or double centrifugation (double centrifugation group, DCG). In the patients in the single and double centrifugation groups, bone marrow was harvested from the iliac bone. Six months after the grafting procedures, bone biopsy specimens were obtained during implant placement and were analyzed by histomorphometry. Results: Histomorphometric analysis revealed a great amount of vital mineralized tissue in SCG followed by DCG when compared with the CG (38.44 ± 12.34%, 34.63 ± 9.84%, and 27.30 ± 5.55%, respectively). SCG and DCG presented smaller amounts of nonvital mineralized tissue when compared with the CG (13.70 ± 7.50%, 19.63 ± 8.35%, and 22.79 ± 9.60%, respectively), thus presenting higher levels of resorption. Although these differences were not statistically significant (P > .05), a tendency toward bone gain in the experimental groups (SCG and DCG) was found. All groups (SCG, DCG, and CG) showed similar levels of nonmineralized tissue (47.87 ± 6.31%, 45.73 ± 7.33%, and 49.90 ± 7.64%, respectively). Conclusion: This pilot study indicates that the clinical use of bone marrow aspirate concentrate, obtained by either a single or double centrifugation process, combined with a xenograft for maxillary sinus elevation seems to result in more adequate bone repair. However, clinical trials with a larger number of patients are required. Schlagwörter: bone marrow, bone substitutes, clinical research, sinus floor augmentation

Purpose: To assess and compare topographic features and preosteoblastic cell responses of a new hydrothermally treated, calcium-incorporated surface against other commercially available implant surfaces. Materials and Methods: Four different surfaces were the subject of comparison in this study: machined (MC), resorbable blast media (RBM), sandblasted/large-grit/acid-etched (SLA), and calciumincorporated SLA (Ca-SLA). Surface morphology and roughness were first characterized by scanning electron microscope (SEM) and white light interferometer, respectively. Preosteoblastic MC3T3-E1 cells were then cultured on the titanium surfaces. Cell morphology was observed at 24 hours, 48 hours, 7 days, and 15 days by SEM; differentiation was assessed at 7, 11, and 15 days by assaying alkaline phosphatase (ALP) activity and osteocalcin (OCN) levels. Results: Surface characterization revealed nanotopographic features on Ca-SLA. At topographic analysis, SLA and Ca-SLA showed similar roughness values. Significant differences in cell differentiation parameters were found only at 15 days between the SLA surfaces (both Ca-incorporated and nonincorporated) and MC. Conclusion: Collectively, this study demonstrated that hydrothermal treatment determines the formation of nanotopography without altering the SLA microtopography. Moreover, Ca-SLA and SLA induce MC3T3-E1 cell differentiation at comparable levels. Schlagwörter: calcium ions, implant, implant surfaces, surface roughness, surface treatment

Purpose: To optimize methods for seeding cells on granular-type beta-tricalcium phosphate (β-TCP). Materials and Methods: Bone marrow stromal cells were obtained from rat long bones and cultured in flasks with Minimum Essential Medium, Alpha Modification (αMEM) supplemented with 10% fetal bovine serum (FBS), dexamethasone, ascorbic acid, β-glycerophosphate, and antibiotics. The influence of differential cell seeding densities and dynamic cell seeding conditions (rotation) was investigated using different sizes of β-TCP granules and a subcutaneous implantation model. Results: Higher cell seeding densities contributed to efficient in vivo bone formation. The rotational seeding did not affect the efficiency but contributed to the uniformity. Although the granule size did not affect the efficiency under the conditions used in this study, large granules showed more uniform distribution of bone regeneration, while small granules showed nonuniform but dense bone formation. Mixtures of relatively large and small granules may be beneficial for both uniform and efficient bone regeneration. Conclusion: These findings may contribute to stable bone tissue engineering with bone marrow stromal cells and β-TCP granules as a scaffold. Schlagwörter: bone tissue engineering, β-TCP, cell seeding, granular scaffold, in vivo bone formation