Showing papers in "Clinical Implant Dentistry and Related Research in 2016"

Foreign Body Reaction to Biomaterials: On Mechanisms for Buildup and Breakdown of Osseointegration.

Abstract: Background The last few decades have seen a progressive shift in paradigm, replacing the notion of body implants as inert biomaterials for that of immune-modulating interactions with the host. Purpose This text represents an attempt at understanding the current knowledge on the healing mechanisms controlling implant–host interactions, thus interpreting osseointegration and the peri-implant bone loss phenomena also from an immunological point of view. Materials and Methods A narrative review approach was taken in the development of this article. Results Osseointegration, actually representing a foreign body reaction (FBR) to biomaterials, is an immune-modulated, multifactorial, and complex healing process where a number of cells and mediators are involved. The buildup of osseointegration seems to be an immunologically and inflammatory-driven process, with the ultimate end to shield off the foreign material placed in the body, triggered by surface protein adsorption, complement activation, and buildup of a fibrin matrix, followed by recruitment of granulocytes, mesenchymal stem cells, and monocytes/macrophages, with the latter largely controlling the longer term response, further fusing into foreign body giant cells (FBGC), while bone cells make and remodel hydroxyl apatite. The above sequence results in the FBR that we call osseointegration and use for clinical purposes. However, the long-term clinical function is dependent on a foreign body equilibrium, that if disturbed may lead to impaired clinical function of the implant, through a breakdown process where macrophages are again activated and may further fuse into FBGCs, now seen in much greater numbers, resulting in the start of bone resorption – due to cells such as osteoclasts with different origins and possibly even macrophages degrading more bone than what is formed via osteoblastic activity – and rupture of mucosal seals, through complex mechanisms in need of further understanding. Infection may follow as a secondary event, further complicating the clinical scenario. Implant failure may ensue. Conclusions Dentistry is still to embrace the concept of the biomaterials' healing- and immune-modulating effect when in contact with body tissues. The presented knowledge has the potential to open the door for a different interpretation of past, current, and future observations in dental implant science. From a clinical standpoint, it seems recommendable to react as rapidly as possible when facing peri-implant bone loss, trying to reestablish a foreign body equilibrium if with some bone resorption.

"Peri-Implantitis": A Complication of a Foreign Body or a Man-Made "Disease". Facts and Fiction.

Abstract: Background The discrepancy between some scientific views and the daily clinical experience with dental implants has made the topic of “periimplantitis” highly controversial, especially the discussion whether “periimplantitis” should even be considered a “disease” or whether marginal bone loss instead would represent a complication of having a foreign body placed in the oral cavity. Purpose The aim of the present paper was to present the outcomes from a consensus meeting on “peri-implantitis” in Rome, Italy (January 8–10, 2016). Materials and Methods Seventeen clinical scientists were invited to, based on prepared reviews of the literature, discuss topics related to “periimplantitis.” Results and conclusions Oral implants may lose bone or even display clinical failure. However, progressive bone loss threatening implant survival is rare and limited to a percent or two of all implants followed up over 10 years or more, provided that controlled implant systems are being used by properly trained clinicians. There is very little evidence pointing to implants suffering from a defined disease entity entitled “peri-implantitis.” Marginal bone loss around implants is in the great majority of cases associated with immune-osteolytic reactions. Complicating factors include patient genetic disorders, patient smoking, cement or impression material remnants in the peri-implant sulcus, bacterial contamination of the implant components and technical issues such as loose screws, mobile components or fractured materials. These reactions combine to result in cellular responses with the end result being a shift in the delicate balance between the osteoblast and the osteoclast resulting in bone resorption. However, the great majority of controlled implants display a foreign body equilibrium resulting in very high survival rates of the implants over long term of follow-up.

The Effects of Alveolar Ridge Preservation: A Meta-Analysis.

Abstract: Purpose The aim of this article was to analyze the horizontal, vertical, and histological effects of alveolar ridge preservation (ARP) versus the ones of unassisted socket healing, in the format of an up-to-date review and meta-analysis. Materials and Methods An extensive electronic search in the electronic databases of the National Library of Medicine was conducted for articles published up to June 2014 to identify literature presenting data on the topic of ARP. Only randomized controlled trials, controlled clinical trials, and prospective trials were included for meta-analysis. Results After screening 903 abstracts from the electronic database, we included 64 studies in qualitative and 18 in quantitative synthesis. Quality assessment characterized a medium risk of bias for the included literature. The meta-analysis showed a mean difference between test and control groups of approximately 1.31 to 1.54 mm in bucco-oral bone width and 0.91 to 1.12 mm in bone height. Additionally, the intergroup difference in percentage of vital bone was assessed to be inconclusive across the included studies. Implants could be inserted into the determined position without further augmentation in 90.1% of the experimental sites, while this was the case in only 79.2% of the control sockets. Conclusions Resorption of the alveolar ridge cannot be totally stopped by ARP, while it still can be prevented compared with unassisted healing. No reliable predictions on the histological effects could be made due to limited data. Further on, no recommendation for a specific technique of ARP could be made. In conclusion, there is still need for ongoing research on the topic, even though the lower percentage of implant sites that needed additional augmentation in test sockets seemed to bring a patient benefit.

Health, Maintenance, and Recovery of Soft Tissues around Implants.

Abstract: Background The health of peri-implant soft tissues is one of the most important aspects of osseointegration necessary for the long-term survival of dental implants. Purpose To review the process of soft tissue healing around osseointegrated implants and discuss the maintenance requirements as well as the possible short-comings of peri-implant soft tissue integration. Materials and Methods Literature search on the process involved in osseointegration, soft tissue healing and currently available treatment modalities was performed and a brief description of each process was provided. Results The peri-implant interface has been shown to be less effective than natural teeth in resisting bacterial invasion because gingival fiber alignment and reduced vascular supply make it more vulnerable to subsequent peri-implant disease and future bone loss around implants. And we summarized common procedures which have been shown to be effective in preventing peri-implantitis disease progression as well as clinical techniques utilized to regenerate soft tissues with bone loss in advanced cases of peri-implantitis. Conclusion Due to the difference between peri-implant interface and natural teeth, clinicians and patients should pay more attention in the maintenance and recovery of soft tissues around implants.

Does Bruxism Contribute to Dental Implant Failure? A Systematic Review and Meta-Analysis.

Abstract: Background Bruxism was usually considered as a contraindication for oral implanting. The causal relationship between bruxism and dental implant failure was remained controversial in existing literatures. Purpose This meta-analysis was performed to investigate the relationship between them. Materials and Methods This review conducted an electronic systematic literature search in MEDLINE (PubMed) and EmBase in Novermber 2013 without time and language restrictions. Meanwhile, a hand searching for all the relevant references of included studies was also conducted. Study information extraction and methodological quality assessments were accomplished by two reviewers independently. A discussion ensued if any disagreement occurred, and unresolved issues were solved by consulting a third reviewer. Methodological quality was assessed by using the Newcastle-Ottawa Scale tool. Odds ratio (OR) with 95% confidence interval (CI) was pooled to estimate the relative effect of bruxism on dental implant failures. Fixed effects model was used initially; if the heterogeneity was high, random effects model was chosen for meta-analysis. Statistical analyses were carried out by using Review Manager 5.1. Results In this meta-analysis review, extracted data were classified into two groups based on different units. Units were based on the number of prostheses (group A) and the number of patients (group B). In group A, the total pooled OR of bruxers versus nonbruxers for all subgroups was 4.72 (95% CI: 2.66–8.36, p = .07). In group B, the total pooled OR of bruxers versus nonbruxers for all subgroups was 3.83 (95% CI: 2.12–6.94, p = .22). Conclusions This meta-analysis was performed to evaluate the relationship between bruxism and dental implant failure. In contrast to nonbruxers, prostheses in bruxers had a higher failure rate. It suggests that bruxism is a contributing factor of causing the occurrence of dental implant technical/biological complications and plays a role in dental implant failure.

The Effect of Insertion Torque on the Clinical Outcome of Single Implants: A Randomized Clinical Trial

Abstract: Background The insertion torque value has been extensively used as an indicator for implant primary stability, which is considered a determining parameter for the implants success. Purpose The primary goal of the present randomized clinical trial was to evaluate and compare the clinical outcome for implants placed with high insertion torque (between 50 Ncm and 100 Ncm) and regular insertion torque (within 50 Ncm) in healed ridges. Materials and Methods Partially edentulous patients, missing one or more mandibular or maxillary teeth, having an adequate amount of bone, requiring implant placement, were randomized to receive Blossom CT implants with regular insertion torque (<50 Ncm) or CT implants with high insertion torque (≥50 Ncm). Implants were left to heal submerged for 3 months. Implants were restored with individualized abutments and cemented metal-ceramic crowns. Acquired measurements were: insertion torque values (IT), thickness of buccal bone plate after implant osteotomy preparation (BBT), marginal bone level (MBL), and facial soft tissue level (FST). All patients were followed 12 months after implant placement. Results One hundred sixteen implants were placed in one hundred sixteen patients and enrolled for the study. Fifty-eight implants were randomly allocated in regular-IT and high-IT groups with a mean insertion torque ranging from 20 Ncm to 50 Ncm and from 50 Ncm to 100 Ncm, respectively. Three implants failed, and another five implants showed at the 12-month evaluation a marginal bone loss (ΔMBL) greater than 1.5 mm, being considered unsuccessful. Conclusions The findings suggested that implants inserted with high-IT (≥50 Ncm) in healed bone ridges showed more peri-implant bone remodeling and buccal soft tissue recession than implants inserted with a regular-IT (<50 Ncm). Moreover, sites with a thick buccal bone wall (≥1 mm) – after implant osteotomy site preparation – seemed to be less prone to buccal soft tissue recession after 12 months than sites with a thin buccal bone wall (<1 mm).

Vertical Bone Augmentation with an Autogenous Block or Particles in Combination with Guided Bone Regeneration: A Clinical and Histological Preliminary Study in Humans.

Abstract: Background Vertical ridge augmentation with the use of solid bone blocks or particulate bone autograft, exposed or covered by a nonresorbable expanded polytetrafluoroethylene (ePTFE) membrane, are well known in the literature and have been shown to be effective in treating bone atrophy. Purpose The aim of our study was to assess the two techniques in respect to biological properties of transplanted bone in graft revascularization and bone remodeling in conjunction with dental implants. Materials and Methods Ten patients were treated within the study, with a total of 12 sites with posterior mandibular edentulous ridges with insufficient bone to allow implant placement. Bone regeneration was performed using autogenous intraoral block graft or autogenous particulate graft with an ePTFE barrier membrane. At 6–10 months, reentry surgery was performed; bone biopsies, including microscrews, were harvested; and implants were placed. Results Eleven sites out of 12 healed uneventfully. A mean height gain of 5.03 mm was achieved. Mean bone-to-implant contact and bone fill were assessed by means of histomorphometric analysis. The block specimens revealed a bone-to-implant contact of 42.34%, and the particulate grafts had a bone-to-implant contact of 26.62% (p < .012). Bone fill values reported were 68.32% and 48.28% (p < .019) for block specimens versus particulate grafts. Conclusions The results clearly showed that both techniques were clinically successful for subsequent implant placement and prosthetic rehabilitation. The histological outcomes, including revascularization and bone remodeling, of the two techniques differed significantly. The block grafts outperformed the particulate grafts in terms of bone-to-implant contact and bone fill values; however, the morbidity associated with the donor site of the block must be considered.

Influence of Skeletal and Local Bone Density on Dental Implant Stability in Patients with Osteoporosis

Abstract: Background and Purpose Osteoporosis is a major skeletal disease affecting millions of people worldwide. Recent studies claim that patients with osteoporosis do not have a higher risk of early implant failure compared to non-osteoporotic patients. The aim of this study was to assess the effect of skeletal osteoporosis and local bone density on initial dental implant stability. Materials and Methods Seventy-three patients were recruited and were assigned (based on a Dual-energy X-ray Absorptiometry scan) to either the osteoporosis (Opr), osteopenia (Opn), or control (C) group. Forty nine of the 73 patients received dental implants and had implant stability measured by means of resonance frequency analysis (RFA) at implant placement and at prosthetic abutment placement. On the computerized tomography scans, the cortical thickness and the bone density (Hounsfield Units) at the sites of implant placement were measured. Results At implant placement, primary stability was on average lower in group Opr (63.3 ± 10.3 ISQ) than in group Opn (65.3 ± 7.5 implant stability qutient (ISQ)), and group C (66.7 ± 8.7 ISQ). At abutment placement, a similar trend was observed: group Opr (66.4 ± 9.5 ISQ) scored lower than group Opn (70.7 ± 7.8 ISQ), while the highest average was for group C (72.2 ± 7.2 ISQ). The difference between groups Opr and C was significant. Implant length and diameter did not have a significant effect on implant stability as measured with RFA. A significant correlation was found between local bone density and implant stability for all regions of interest. Conclusions Implant stability seems to be influenced by both local and skeletal bone densities. The lower stability scores in patient with skeletal osteoporosis reinforce the recommendations that safe protocols and longer healing times could be recommended when treating those patients with dental implants.

Recent Trends in Sinus Lift Surgery and Their Clinical Implications.

Abstract: Background Sinus lift procedures are used to allow residual bone to accommodate functional implants in atrophic posterior maxilla. Numerous anatomical and surgical advancements in sinus lift surgery are still inspiring clinicians. Purpose The purpose of this study was to describe the recent trends in sinus lift surgery focusing on implant survival, bone grafting, anatomical and surgical considerations, and their clinical implications on the practice of implant dentistry in atrophic posterior maxilla. Materials and Methods We performed an extensive search in MEDLINE, Embase, Scopus, Web of Science, Trip, Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials, and ProQuest Dissertations & Theses. Articles were critically reviewed to determine the level of evidence as per the Canadian Task Force on Preventive Health Care. Results Comprehensive assessment of sinus septa, sinus pathology, and bone quality and quantity using three-dimensional cone beam computed tomography radiographs is important before placing implants in posterior maxilla. With a residual bone height of less than 5 mm, the survival rate of implant decreases substantially. Lateral window approach can increase the vertical bone height to greater than 9 mm, while osteotome approach can increase this height from 3 to 9 mm. The perforation of Schneiderian membrane doubles the risk for the incidence of sinusitis or infection. The use of piezoelectric surgery allows adequate sinus lift while protecting soft tissues and minimizing patient discomfort. Conclusions Although both osteotome and lateral window procedures can help clinicians in overcoming the challenges of placing implants in atrophic posterior maxilla, pre-implant residual bone height is crucial in determining the survival of these implants. Future research directions should consider study designs grounded on longitudinal randomized controlled trials of large sample size.

Ultrasonic Assessment of Mucosal Thickness around Implants: Validity, Reproducibility, and Stability of Connective Tissue Grafts at the Buccal Aspect

Abstract: Purpose: (1) To assess validity and reproducibility of mucosal thickness (MT) registration by means of an ultrasonic device and (2) to determine MT stability of connective tissue grafts (CTG) when applied at the buccal aspect of single implants demonstrating alveolar process deficiency. Materials and Methods: For the validity assessment, 4 human cadaver edentulous maxillae were used to determine MT at 100 different sites. Soft tissue thickness as recorded with the ultrasonic device was compared to MT as registered with Micro-CT, taking the latter as gold standard. For the reproducibility assessment, 50 duplicate ultrasonic registrations were used. For the clinical part, 10 non-smoking patients with a single implant were included. All demonstrated alveolar process deficiency and had been provided with a provisional screw-retained crown at the time of inclusion. Following an intra-sulcular incision at the buccal aspect, a CTG was inserted to thicken soft tissues. MT was assessed at t0 (before CTG), t1 (immediately after CTG), t2 (suture removal), t3 (permanent crown installation) and t4 (9 months after CTG). Results: There was a strong correlation between ultrasonic and Micro-CT measurements (r=0.89, p<0.001). However, the former significantly underrated MT by 0.13 mm (p=0.030). There was a strong correlation between duplicate ultrasonic recordings (r=0.99, p<0.001). Seven females and 3 males were included in the clinical study with a mean age of 52. MT significantly increased by 0.92 mm between t0 and t1 (p=0.005). Between t3 and t4 there was a slight, yet significant decrease of 0.15 mm (p=0.047). Conclusion: The ultrasonic device can be used as a non-invasive, reliable and reproducible method to evaluate MT. Using this technology around single implants demonstrated that CTG may substantially thicken the peri-implant mucosa with acceptable stability over a 9-month period.

Five-Year Results of a Randomized Controlled Trial Comparing Patients Rehabilitated with Immediately Loaded Maxillary Cross-Arch Fixed Dental Prosthesis Supported by Four or Six Implants Placed Using Guided Surgery.

Abstract: Purpose To compare the 5-year clinical and radiological outcomes of patients rehabilitated with four or six implants placed using guided surgery and immediate function concept. Materials and Methods Forty patients randomly received four (All-on-4) or six (All-on-6) immediately loaded implants, placed using guided surgery, to support a cross-arch fixed dental prosthesis. Outcome measures were survival rates of implants and prostheses, complications, peri-implant marginal bone loss, and periodontal parameters. Results No drop-out occurred. Seven implants failed at the 5-year follow-up examination: six in the All-on-6 group (5%) and one in the All-on-4 group (1.25%), with no statistically significant differences (p = .246). No prosthetic failure occurred. Both group experienced some technical and biologic complications with no statistically significant differences between groups (p = .501). All-on-4 treatment concept demonstrated a trend of more complications during the entire follow-up period. A trend of more implant failure was experienced for the All-on-6 treatment concept. Marginal bone loss (MBL) from baseline to the 5-year follow-up was not statistically different between All-on-4 (1.71 ± 0.42 mm) and All-on-6 (1.51 ± 0.36 mm) groups (p = .12). For periodontal parameters, there were no differences between groups (p > .05). Conclusion Both approaches may represent a predictable treatment option for the rehabilitation of complete edentulous patients in the medium term. Longer randomized controlled studies are needed to confirm these results.

Esthetic Evaluation of Implant Crowns and Peri‐Implant Soft Tissue in the Anterior Maxilla: Comparison and Reproducibility of Three Different Indices

Abstract: BACKGROUND A successful implant reconstruction with optimal esthetics consists of a visually pleasing prosthesis and complete and healthy surrounding soft tissue. In the current literature, numerous indices used to qualitatively assess esthetics have been described. However, studies comparing the indices and their reproducibility are scarce. PURPOSE The aim of this study was to compare three different esthetic indices for the evaluation of single implant-supported crowns. MATERIALS AND METHODS A total of 10 prosthodontists (P), 10 orthodontists (O), 10 general dentists (G), and 10 lay people (L) independently performed the same assessment using 30 photographs and corresponding casts with three different esthetic indices (Peri-Implant and Crown Index [PICI], Implant Crown Aesthetic Index [ICAI], "Pink Esthetic Score/White Esthetic Score [PES/WES]) and repeated the evaluations 4 weeks later. RESULTS The PES/WES and the PICI showed significantly higher esthetic scores (pink, white, total) and clinical acceptance compared with the ICAI in all four groups and in both assessments. The highest intraobserver agreement was achieved using the PES/WES and the least with the ICAI. The mean Kappa per group ranged from 0.18 (group L with ICAI) to 0.63 (group G with PICI). CONCLUSION In comparison with the ICAI, the PES/WES and PICI were more reproducible. Therefore, PES/WES and PICI seem to be more suitable as esthetic indices for single implant crowns.

Influence of Glycemic Control on Peri‐Implant Bone Healing: 12‐Month Outcomes of Local Release of Bone‐Related Factors and Implant Stabilization in Type 2 Diabetics

Abstract: Background The poor glycemic status seems to be an important factor affecting implant complication rates, including peri-implant bone loss. Purpose This trial evaluated the influence of glycemic control of type 2 diabetes mellitus (T2DM) patients on implant stabilization and on the levels of bone markers in peri-implant fluid during the healing. Materials and Methods Systemically healthy patients (SH,n = 19), better-controlled T2DM (BCDM,n = 16), and poorly controlled T2DM (PCDM,n = 16) indicated for implant therapy were recruited. The implant stability quotient (ISQ) was determined at implant placement, 3, 6, and 12 months. Levels of transforming growth factor- β (TGF-β), fibroblast growth factor (FGF), osteopontin (OPN), osteocalcin (OC), and osteoprotegerin (OPG) in the peri-implant fluid were quantified at 15 days, and 3, 6, and 12 months, using the Luminex assay. Results OPG and OPN levels were higher in SH at 12 months than at15 days (p .05). No difference in ISQ was observed among groups over time (p > .05). Conclusion Poor glycemic control negatively modulated the bone factors during healing, although T2DM, regardless of glycemic status, had no effect on implant stabilization.

Early Implant Failures Related to Individual Surgeons: An Analysis Covering 11,074 Operations Performed during 28 Years.

Abstract: Background Compared with knowledge on patient and implant component factors, little knowledge is available on surgeons' role in early implant failures. Purpose To report incidence of early implant failures related to total number of operations performed by individual surgeons. Materials and Methods Early implant failures (≤1 year of implant prosthesis function) were reported after a total of 11,074 implant operations at one specialist clinic during 28 years of surgery. Altogether, 8,808 individual patients were treated by 23 different dentists, of whom 21 surgeons were specialists in oral surgery or periodontology. Recorded failures were related to total numbers of performed operations per surgeon, followed by statistical comparisons (χ2) between surgeons with regard to type of treated jaw and implant surface. Results Altogether, 616 operations were recorded with early implant failures (5.6%), most often observed in edentulous upper jaws after placing implants with a turned surface (p < .05). Significant differences between surgeons, gender of surgeon, type of treated jaws by the surgeon, and implant surface used by the surgeon could be observed (p < .05). Conclusions Early implant failures are complex, multifactorial problems associated with many aspects in the surgical procedure. A stochastic variation of failures for individual surgeons could be observed over the years. Different levels of failure rate could be observed between the surgeons, occasionally reaching significant levels as a total or for different jaw situations (p < .05). The surgeons reduced their failure rates when using implants with moderately rough surfaces (p < .5), but the relationship of failure rate between the surgeons was maintained.

A 9-Year Prospective Case Series Using Multivariate Analyses to Identify Predictors of Early and Late Peri-Implant Bone Loss.

Abstract: PURPOSE To identify predictors of early and late peri-implant bone loss following complete implant-supported rehabilitation using multivariate analyses.MATERIALS & METHODS 50 patients (28 women, 22 men; mean age 58, range 35-76) in need for a complete implant-supported rehabilitation on 5 to 8 implants were consecutively treated. Patients were reinvited for a clinical and radiographic examination after on average 9 years of function. Implant survival and peri-implant bone loss were considered the dependent variables. Multivariate analyses were adopted to identify predictors of early and late peri-implant bone loss.RESULTS In total, 39 patients were examinated. Two implants failed after 4 years of funtion, resulting in an overall survival rate of 99.2 %. After a mean follow-up of 9 years, mean bone loss of 1.68 mm (SD 2.08, range -1.05 – 10.95) was found. The abutment height was a significant predictor of early peri-implant bone loss (1 year) (p = 0.024), whereas smoking (p = 0.046) and history of periodontitis (p = 0.046) affected late peri-implant bone loss.CONCLUSION Within the limits of this study, it can be concluded that initial bone remodeling was affected by soft tissue thickness as reflected by the height of the abutment, whereas smoking and history of periodontitis affected long-term peri-implant bone stability.

Short Implants Placed with or without Grafting in Atrophic Sinuses: The 3-Year Results of a Prospective Randomized Controlled Study.

Abstract: Background The question whether a minimal maxillary residual bone height (RBH) allows the predictable use of osteotome sinus floor elevation (OSFE) remains unresolved. Purpose To evaluate the efficacy of short implants placed with OSFE in an RBH of ≤4 mm and to compare bone levels around implants placed with (control) or without (test) grafting after 3 years. Materials and Methods Eight-millimeter implants were placed by OSFE in sinuses randomized to receive anorganic bovine bone or no grafting material. Healing time before prosthetic rehabilitation was 10 weeks. Peri-implant bone levels were measured on standardized periapical radiographs. Results Thirty-seven implants (17 test, 20 control) were placed at a mean RBH of 2.4 ± 0.9 mm. Three implants failed during the 3-year follow-up. After 3 years, all implants had gained endosinus bone (test: 4.1 ± 1.0 mm; control: 5.1 ± 1.2 mm; p = .001). Mean bone gain was stable between 1 and 3 years in both groups. Conclusions Grafting is unnecessary to achieve bone augmentation of 4.1 mm; however, more bone is gained with grafting. Bone gained over 1 year was retained. Atrophic posterior maxillae can be predictably rehabilitated using OSFE and simultaneous placement of 8-mm implants.

Clinical Fitting and Adjustment Time for Implant‐Supported Crowns Comparing Digital and Conventional Workflows

Abstract: PURPOSE The aim of this prospective cohort study was to investigate clinical and laboratory performance of implant-supported reconstructions comparing the digital to the conventional workflow. MATERIALS AND METHODS Twenty study participants were treated in a cross-over design for single-tooth replacement in posterior sites, each with a customized titanium abutment plus computer-assisted design and computer-assisted manufacturing (CAD/CAM)-zirconia-suprastructure (test: digital workflow; n = 20) and a standardized titanium abutment plus PFM-crown (control: conventional pathway; n = 20). Evaluation of the 40 reconstructions included: 1) feasibility of laboratory cross-mounting of each abutment-crown-connection, and 2) assessment of adaptation time for clinical adjustments of interproximal and occlusal surfaces. Statistical analyses were performed using the exact Wilcoxon rank sum tests. RESULTS Laboratory cross-mounting was feasible for three reconstruction pairings revealing a 15% vice versa transfer success rate. All implant crowns could be provided successfully within two clinical appointments, independently of the workflow used. The mean clinical adjustment time was significantly lower (p < .001) for test reconstructions from the digital workflow with 2.2 min (standard deviation [SD] ± 2.1) compared with the ones from the conventional pathway with 6.0 min (SD ± 3.9). CONCLUSIONS The digital workflow was almost threefold more efficient than the established conventional pathway for fixed implant-supported crowns. Clinical fitting could be predictably achieved with no or minor adjustments within the digital process of intraoral scanning plus CAD/CAM technology.

Clinical Bonding of Resin Nano Ceramic Restorations to Zirconia Abutments: A Case Series within a Randomized Clinical Trial.

Abstract: Background: New dental materials are introduced and promoted in the field without extensive clinical testing. Using those materials in a clinical setting might result in unacceptable early failure rates. Purpose: The purpose of this paper was to analyze bonding of a new dental restorative material to either zirconia stock abutments or zirconia customized abutments. Materials and Methods: Fifty participants seeking single implant treatment were included in a prospective study. Resin Nano Ceramic (RNC, Lava Ultimate, 3M ESPE, Seefeld, Germany) crowns were digitally manufactured and extraorally bonded to either a stock or a customized zirconia abutment (ZirDesign and ATLANTIS, DENTSPLY Implants, Molndal, Sweden) by means of a resin composite cement (RelyX Ultimate in combination with Scotchbond Universal, 3M ESPE), strictly following the manufacturer's recommendations. The final restorations were screw-retained to the implants and followed during 12 months. Primary outcome parameter was uncompromised survival of the restoration, and secondary outcome parameter was mode of failure. Results: No implants were lost. The uncompromised survival rate of the RNC crowns bonded to zirconia abutments after 1 year of clinical service was only 14% (n = 7). Catastrophic failure occurred in three cases (6%), whereas bonding failure between RNC crowns and zirconia abutments occurred in 80% of the cases (n = 40) within the first year of service. No statistical significant difference in uncompromised survival rate could be identified between abutment types (chi(2) = 1.495, p =.209). Uncompromised survival rate after 1 year was highly significantly different (chi(2) = 104.173, p Conclusion: RNC crowns luted to stock and customized zirconia implant abutments with the particular resin composite cement in this trial have a poor prognosis, regardless of the abutment type used.

Accuracy of Three‐Dimensional Printed Templates for Guided Implant Placement Based on Matching a Surface Scan with CBCT

Abstract: BACKGROUND Reference elements are necessary to transfer a virtual planning into reality for guided implant placement. New systems allow matching optical scans with three-dimensional radiographic images. PURPOSE To test whether digitally designed three-dimensional printed templates (D-temp) fabricated by matching surface scans and cone beam computed tomography (CBCT) images differ from the templates fabricated in-lab (L-temp) by using a physical transfer device for the positioning of the guiding sleeves. MATERIALS AND METHODS L-temp were fabricated for eight human lower cadaver-jaws applying a digital planning software program (smop, Swissmeda AG, Zurich, Switzerland) using a Lego® (Lego Group, KIRKBI A/S, Billund, Denmark) brick as reference element and the respective transfer device (X1-table). Additionally, digital templates (D-temp) using the identical planning data sets and software were virtually designed and three-dimensional printed, after matching a surface scan with CBCT data. The accuracy of both templates for each planning was evaluated determining the estimated coronal, apical, and angular deviation if templates were used for implant placement. RESULTS Mean coronal deviations for L-temp were 0.31 mm (mesial/distal), 0.32 mm (lingual/buccal), and 0.16 mm and 0.23 mm for D-temp, respectively. The mean apical deviations for L-temp were 0.50 mm (mesial/distal), 0.50 mm (lingual/buccal). and 0.25 mm and 0.34 mm for the D-temp, respectively. Differences between both devices were statistically significant (p < .05). CONCLUSIONS A higher accuracy of implant placement can be achieved by using three-dimensional printed templates produced by matching a surface scan and CBCT as compared with templates which use physical elements transferring the virtual planning into reality.

Immediate Implant Placement into Extraction Sockets with Labial Plate Dehiscence Defects: A Clinical Case Series.

Abstract: Purpose To measure the buccal plate reconstruction of extraction sockets with labial plate dehiscence defects using a bone allograft in combination with an absorbable collagen membrane and a custom-healing abutment at the time of tooth removal. Materials and Methods Ten patients underwent immediate implant placement and reconstruction of the buccal plate. Cone beam computed tomography (CBCT) was performed preextraction, immediately after bone grafting and implant placement (day 0), and between 6 and 9 months following implant surgery. Measurements were taken at three levels: coronal (L1), middle (L2), and apical (L3) level. Results Implants placed into sockets with labial plate dehiscence defects demonstrated radiographic reformation of the labial plate dehiscence defect at 6 to 9 months posttreatment. The net gain in labial plate on cone beam computerized tomography (CBCT) in L1 and L2 was 3.0 mm, where 0 mm existed at pretreatment. The minimum amount of labial plate thickness of 2.0 mm was achieved in all treated sites, evaluated radiographically at 6 to 9 months postoperatively, in a single procedure, without flap elevation and maintaining the gingival architecture and satisfactory esthetics. Conclusion Placing an absorbable membrane, bone graft, and custom-healing abutment at the time of flapless anterior tooth extraction and immediate implant placement into a socket with a labial osseous dehiscence is a viable clinical technique to reconstitute the absence of the labial bone plate.

Osteotome Sinus Floor Elevation without Grafting: A 10-Year Prospective Study.

Abstract: The study aims to evaluate the long-term efficiency of the procedure and stability of the peri-implant bone formed following implant placement without grafting into resorbed posterior maxilla.

Long-term Survival of Straumann Dental Implants with TPS Surfaces: A Retrospective Study with a Follow-up of 12 to 23 Years.

Abstract: Purpose The aim of this study was to evaluate the long-term dental implant survival rates of Straumann dental implants in a university hospital environment over 12 to 23 years. Materials and Methods A total of 388 Straumann dental implants with titanium-sprayed surfaces (TPS) were inserted in 92 patients between 1988 and 1999 in the Department of Oral and Maxillofacial Surgery of the University Hospital Schleswig-Holstein in Kiel, and they were reevaluated with standardized clinical and radiological exams. Kaplan–Meier analyses were performed for individual factors. Cox proportional hazard regression analysis was used to detect the factors influencing long-term implant failure. Results The long-term implant survival rate was 88.03% after an observation time of 12.2 to 23.5 years. Cox regression revealed statistically significant influences of the International Team for Implantology (ITI) implantation type (p = .00354) and tobacco smoking (p = .01264) on implant failure. A proportion 82.8% of the patients with implant losses had a medical history of periodontitis. Peri-implantitis was diagnosed in 9.7% of the remaining implants in the long-term survey. Conclusions This study emphasized the long-term rehabilitation capabilities of Straumann dental implants in complex cases. The survival rates after several years constitute important information for patients, as well as for clinicians, in deciding about different concepts of tooth replacement. Patient-related and technical factors – determined before implant placement – could help to predict the risk of implant loss.

A Prospective Longitudinal Study on Implant Prosthetic Rehabilitation in Controlled HIV-Positive Patients with 1-Year Follow-Up: The Role of CD4+ Level, Smoking Habits, and Oral Hygiene.

Abstract: Background A recent study showed that implant-prosthetic rehabilitation in well-controlled HIV patients gave slightly worse results than in an healthy population, and failures were all linked to infection. Purpose The aim of this study was to examine the associations between the success of implant-prosthetic treatment and systemic CD4+ level, smoking habits, and oral hygiene. Materials and Methods This mono-centric study included HIV patients with a stable disease and good oral hygiene requiring implant rehabilitation. Each patient received at least one dental implant. Prosthesis were delivered after 90 days in the upper jaw and 60 days in the lower jaw. Primary outcome measures were prosthetic failures, implant failures, peri-implant marginal bone level changes, and biological complications (peri-implantitis, pus, pain, paresthesia). The possible association with CD4 count, smoking habits, and oral hygiene was analyzed. Results Sixty-eight patients received 194 implants, and 66 patients (190 implants) were followed for 1 year. No significant associations were found between CD4+ count, oral hygiene-associated variables, and any of the outcome measures. If compared with nonsmoking/light smoking patients, patients who smoked >10 cigarettes/day suffered a statistically significant greater number of implant failures (p ≤ .005), presented a comparatively higher number of peri-implantitis (p < .001), as well as a higher frequency of pus (p ≤ .007), and reported pain (p ≤ .009). Conclusion Within the limitation of the present study, placement of dental implants in HIV-positive patients with stable disease seems a reasonable treatment option, regardless of CD4+ cell count, provided that they are in a normal range. Oral hygiene variables were not influent in this group of patient following recall appointments, while HIV-positive heavy smokers (>10 cigarettes/day) demonstrated an increased risk of early implant failure, peri-implantitis, episodes of pus, and self-reported pain.

Two-Center Prospective, Randomized, Clinical, and Radiographic Study Comparing Osteotome Sinus Floor Elevation with or without Bone Graft and Simultaneous Implant Placement.

Abstract: Purpose To evaluate stability and success rate of hydrophilic nanostructured implants placed via osteotome sinus floor elevation (OSFE) without grafting material or using β-tricalcium phosphate (β-TCP), deproteinized bovine bone (DBB), or their combination, and also to assess three-dimensional volumetric stability of endo-sinus bone gained in the aforementioned conditions. Materials and Methods OSFE with simultaneous implant placement (10-mm long SLActive-BL®, Straumann, Basel, Switzerland) was performed. Grafting materials were randomly allocated to implant sites, whereas one site was left without graft. Implant stability was measured by resonance frequency analysis over 6 months. Implant success was evaluated after 2 years of loading. Volume of new endo-sinus bone was calculated from CBCT images using 3D Slicer® software. Results A total of 180 implants were inserted into posterior maxilla of 45 patients with 6.59 ± 0.45 mm of residual bone height, and all remained successful after 2 years. Implant stability steadily increased during healing, without significant difference between groups (p = .658). After 2 years, endo-sinus bone significantly shrank (p < .001) in all groups (DBB:66.34%; β-TCP:61.44%; new bone formed from coagulum: 53.02%; β-TCP + DBB:33.47%). Conclusions Endo-sinus bone gained after OSFE inevitably and significantly shrinks regardless of whether grafting material is applied or not. Grafting material offers no significant advantage to stability nor clinical success of hydrophilic and nanostructured implants placed simultaneously with OSFE.

A Retrospective Clinical Study with Regard to Survival and Success Rates of Zirconia Implants up to and after 7 Years of Loading

Abstract: PURPOSE The study aims to retrospectively investigate the clinical performance of first-generation zirconia implants with a sandblasted surface up to and after 7 years of loading. MATERIALS AND METHODS Clinical records of patients treated with zirconia implants between 2004 and 2009 were screened. Consequently, adequate patients were invited to a clinical and radiographic investigation to classify each implant according to strict success criteria. RESULTS Seventy-one patients receiving 161 implants were available for the evaluation. Overall, 36 implants (22.4%) were lost due to early (n = 14) and late failures (n = 4) or fractures (n = 18). All surviving 125 implants fulfilled the success criteria. None of the investigated implants had a history of peri-implant infections. Mean values with regard to gingival index, plaque index, modified sulcus bleeding index, and probing depth were 0.03, 0.23, 0.59, and 2.80 mm, respectively. The radiographically evaluated mean crestal bone loss was 0.97 ± 0.07 mm. Diameter-reduced implants (3.25 mm) showed lower survival (58.5%) compared with implants with a diameter of 4.0 mm (88.9%) and 5.0 mm (78.6%). The overall longitudinal survival rate was 77.3%. CONCLUSIONS First-generation zirconia implants showed low overall survival and success rates. The evaluated clinical and radiographic parameters were consistent with healthy peri-implant tissues. Additionally, nonfractured failures were not associated with peri-implant infections.

Implant Prosthetic Rehabilitation in Controlled HIV-Positive Patients: A Prospective Longitudinal Study with 1-Year Follow-Up

Abstract: Purpose: The clinical trial aimed to evaluate the survival of implant-prosthetic rehabilitation in controlled HIV-positive patients. Materials and Methods: This mono-centric study included HIV patients with a stable disease, requiring implant rehabilitation, with good oral hygiene. Each patient received at least one dental implant. After 90 days in the upper jaw and 60 days in the lower jaw, the appropriate prosthesis was delivered.Primary outcome measures were prosthetic failures, implant failures, peri-implant marginal bone level changes (MBLCs), and biological complications (peri-implantitis, pus, pain, paresthesia). Data were recorded before the intervention (T0), and 6 (T1) and 12 months (T2) after. Results: Implants were positioned in 68 patients (22 females and 46 males; 194 implants). Two dropouts occurred for exacerbation of the disease before the sixth month of follow-up, and 66 patients (with 190 implants) completed the study. Forty-eight patients (70.6%) received total removable dentures; 11 patients (16.2%) received partial prosthesis, and nine patients (13.2%) received single elements.Implant failure occurred in nine patients (15 fixtures out of 190). These were early implant failures due to primary infection (five fixtures out of 190: 2.6%) and to peri-implantitis (10 fixtures out of 190: 5.2%). Prosthetic failure was registered in two patients (3% of patients) due to the loss of all the fixtures. Pus and pain were observed in 4/7 and 3/7 patients with peri-implantitis, respectively. No fractures of fixtures or paresthesia were registered. At T2, the mean peri-implant MBLC was −1.19 1 0.87 mm. Conclusions: Within its limitations, the study showed that in a well-controlled population of HIV patients implant rehabilitation can be a suitable options with results slightly worse to those obtained in normal population. A higher incidence of peri implant infections in the first six months was present pointing to the need of a proper protocol for infection control.

Osseointegration of Zirconia in the Presence of Multinucleated Giant Cells

Abstract: BACKGROUND Current strategies to reduce medical device-associated infections propose zirconia as a potential implant material which may limit bacterial adhesion. Because multinucleated giant cells (MNGCs) have been detected on these implant surfaces, concerns have been raised regarding tissue integration. PURPOSE The present study examined the presence of MNGCs and their subsequent effect upon tissue integration. Surface-modified implants made of yttria-stabilized (TZP) and alumina-toughened zirconia (ATZ) were compared with commercially pure titanium (Ti). MATERIALS AND METHODS Seven miniature pigs received three implants on either side of the maxilla. After healing periods of 4 and 8 weeks, the tissue response at the implant surfaces was characterized according to three specific parameters: bone-to-implant contact (BIC), MNGC-to-implant contact (MIC), and the peri-implant bone density (BD). RESULTS Despite being present on all tested implant surfaces, MNGCs were not associated with an inflammatory cell infiltrate or with fibrous encapsulation. MNGCs were less numerous on the Ti implants (range: 3.9-5.2%) compared with the ceramic implants (range: 17.6-30.3%, p < .0001). Even though the values of newly formed bone and pristine bone in direct contact with the implant surfaces were high at 4 weeks (tBIC: Ti = 82.3%, TZP = 64.3%, ATZ = 70%), a negative correlation was observed between the presence of MNGCs and newly formed bone at the implant surface (p < .001). Interestingly, the newly formed peri-implant bone density, defined as the percentage of new bone area inside the screw threads (nBD), was not diminished by the presence of MNGCs. CONCLUSIONS Differences in the presence of MNGCs and the BIC parameters between Ti and the ceramic implants appear to be a local cellular phenomenon which is restricted to the implant-bone marrow interface and do not affect the peri-implant bone formation. Factors triggering MNGC differentiation and their persistence in response to biomaterial surface need to be investigated in future studies.

3-Year Randomized Controlled Prospective Clinical Trial on Different CAD-CAM Implant Abutments

Abstract: Background Zirconia abutments were introduced to restore esthetic regions and showed sufficient stability to support implant restorations. Nonetheless, to date the observation periods are shorter than those of titanium abutments. Purpose To assess the survival of implant crowns supported by computer aided design-computer aided manufacturing (CAD-CAM) abutments after 3 years. Materials and Methods Fifty-six patients were selected for this prospective clinical study. Each patient received at least 1 titanium implant for a total of 89 fixtures. A two-stage surgical technique and no additional soft or hard tissue graft were used. The implants were randomly divided into 3 groups receiving different CAD-CAM abutments: titanium, titanium nitride, and zirconia. Zirconia or metal-ceramic crowns were used as final restorations. Cementation was the baseline and the restorations were checked after 6 months, 1, 2, and 3 years, assessing any mechanical complication. Statistical analyses were performed to evaluate the 3-year success rates. Results Five failures were reported in the zirconia group; all the failed restorations showed fractures of the abutment connection. Four failures occurred in posterior regions and one more occurred while screwing the abutment. Titanium and titanium nitride abutments had significantly higher 3-year success rates than zirconia abutments (p < .05). Conclusions Atlantis titanium and titanium nitride abutments showed optimal clinical performances after 3 years. Conversely, Atlantis zirconia abutments should be avoided to restore posterior regions.

Influence of Maxillary Sinus Width on Transcrestal Sinus Augmentation Outcomes: Radiographic Evaluation Based on Cone Beam CT.

Abstract: Background Maxillary sinus elevation is a predictable procedure to vertically enhance bone volume in the posterior maxilla for successful implant placement. It is speculated that graft bone resorption and remodeling which require angiogenesis may be affected by the dimensions of maxillary sinus cavity. Purpose The aim of this study is to investigate the effect of sinus width (SW) on the outcomes of transcrestal sinus lift with simultaneous implant placement based on cone beam CT (CBCT). Materials and Methods A total of 57 elevated sites in 33 patients were included in this study. All the patients were treated with transcrestal sinus lift procedure associated with simultaneous implant placement using a composite graft material of autogenous bone and Bio-Oss. For each patient, CBCT scans were performed preoperatively, immediately after surgery and 6 months after surgery. Measurements of the linear parameters were conducted on the preoperative and postoperative CBCT images. The correlation of SW with graft resorption (GR) was analyzed using Pearson's correlation test with or without the classification of residual bone height. Results The average width of maxillary sinus was 13.68 ± 2.66 mm. The mean height of apical graft bone decreased from 2.85 mm immediately after surgery to 1.38 mm after 6 months. A positive association between SW and GR (r = 0.323, p = .014) was found in general. Conclusion The findings show that graft bone resorption in elevated sinus has a positive correlation with the SW.

Bacterial Composition at the Implant-Abutment Connection under Loading in vivo.

Abstract: Purpose: Platform-switched implants have been demonstrated to prevent bone loss after loading. The present study evaluated bacterial composition of sites from implant-abutment connections of immediately loaded implants, which were placed in the anterior mandible. Ten patients participated in this study. Materials and Methods: A and B implant systems with two different prosthetic connections (Morse tapered vs internal polygonal butt-joint connections, respectively) were placed and loaded for 2 years. The abutments were removed (AB sample) after careful decontamination. Bacterial sampling of the abutments, inner part of the implants (before/visit 1 and after rinsing with chlorhexidine [CHX]/visit 2), and after new abutment connection and loading for 1 additional month, a new sampling (visit 3) was taken to compare the bacteria composition in association with the two connections. Bacterial profiles of samples were determined by using the human oral microbe identification microarray. Results: A total of 240 samples were analyzed taken at different time intervals. Nonparametric statistical analysis (Wilcoxon Rank sum) with uncorrected alpha (p < .05) and after corrections (Benjamini-Hochberg) found no statistical significance between the two connections. No significant changes in the overall microbial profiles were detected at the different time intervals. However, there were trends toward presence of periodontitis-associated species at the B implants in all samples (AB, visit 1, even after CHX irrigation) and after decontamination, abutment replacement, and 1-month loading period. Conclusions: CHX irrigation does not seem to have any effect on decontamination of connections. As shown previously, there is significantly more bone loss around B implants compared with A implants. Although there was no statistical difference in the microbial profiles, there was indeed a trend for the presence of typical periodontal pathogens associated with the internal polygonal butt-joint connection. A possible scenario is that this connection tends to harbor the pathogens that may be involved in subsequent bone loss.