Using Coordination Chemistry to Control "Click" Reactions: The Selective Formation of Asymmetrically Ligated Polyoxometalates.

The Cu(I)-catalyzed azide-alkyne cycloaddition reaction between (NBu4)2[V6O13((OCH2)3CCH2N3)2] and 3-ethynylpyridine led to the formation of products capable of forming poorly soluble coordination compounds with transition metal ions such as Cu(I) and Zn(II). The formation of these poorly soluble phases is an important feature that was used to determine the course of reactions, allowing the selective preparation of symmetric bis-pyridyltriazolyl and asymmetric monopyridyltriazolyl derivatives with relatively high yields and high substrate conversions. The asymmetric compound (NBu4)2[V6O13((OCH2)3CCH2-N3C2H-C5H4N)((OCH2)3CCH2N3)] (V6asym) was utilized in the subsequent "click" postfunctionalization reaction with 1,4-diethynylbenzene, resulting in a covalently bound V6asym-V6asym dimer. This dimeric compound was subjected to scanning probe microscopy studies on gold surfaces, which revealed no electronic coupling between the hexavanadate cores within the dimer upon potential-induced switching. This observation indicates that such dimers and higher-order oligomers composed of polyoxometalate-ligand-polyoxometalate bridges can be exploited as active capacitor/memristor units, relevant to increase the data storage capacity of standard memory devices with innovative molecular switching mechanisms.

Control of Intermediates and Products by Combining Droplet Reactions and Ion Soft-Landing.

Despite being recognized primarily as an analytical technique, mass spectrometry also has a large potential as a synthetic tool, enabling access to advanced synthetic routes by reactions in charged microdroplets or ionic thin layers. Such reactions are special and proceed primarily at surfaces of droplets and thin layers. Partial solvation of the reactants is usually considered to play an important role for reducing the activation barrier, but many mechanistic details still need to be clarified. In our study, we showcase the synergy between two sequentially applied "preparative mass spectrometry" methods: initiating accelerated reactions within microdroplets during electrospray ionization to generate gaseous ionic intermediates in high abundance, which are subsequently mass-selected and soft-landed to react with a provided reagent on a substrate. This allows the generation of products at a nanomolar scale, amenable to further characterization. In this proof-of-concept study, the contrasting reaction pathways between intrinsically neutral and pre-charged reagents, respectively, both in microdroplets and in layers generated by ion soft-landing are investigated. This provides new insights into the role of partially solvated reagents at microdroplet surfaces for increased reaction rates. Additionally, further insights into reactions of ions of the same polarity under various conditions is obtained.

Borane promoted aryl transfer reaction for the synthesis of α-aryl functionalised ß-hydroxy and ß-keto esters.

The synthesis of a series of α-aryl or α-alkyl functionalised ß-hydroxy and ß-keto esters has been achieved by reacting α-diazoesters with boranes, and aldehydes, ketones, anhydrides, nitriles, esters or isocyanates. In a mild reaction protocol, 26 examples are presented in yields up to 73%.

Comparison of 'Mental training' and physical practice in the mediation of a structured facial examination: a quasi randomized, blinded and controlled study.

BACKGROUND: The correct performance of a structured facial examination presents a fundamental clinical skill to detect facial pathologies. However, many students are not adequately prepared in this basic clinical skill. Many argue that the traditional 'See One, Do One' approach is not sufficient to fully master a clinical skill. 'Mental Training' has successfully been used to train psychomotor and technical skills in sports and other surgical fields, but its use in Oral and Maxillofacial Surgery is not described. We conducted a quasi-experimental to determine if 'Mental Training' was effective in teaching a structured facial examination. METHODS: Sixty-seven students were randomly assigned to a 'Mental Training' and 'See One, Do One' group. Both groups received standardized video instruction on how to perform a structured facial examination. The 'See One, Do One' group then received 60 min of guided physical practice while the 'Mental Training' group actively developed a detailed, stepwise sequence of the performance of a structured facial examination and visualized this sequence subvocally before practicing the skill. Student performance was measured shortly after (T1) and five to 10 weeks (T2) after the training by two blinded examiners (E1 and E2) using a validated checklist. RESULTS: Groups did not differ in gender, age or in experience. The 'Mental Training' group averaged significantly more points in T1 (pE1 = 0.00012; pE2 = 0.004; dE1 = 0.86; dE2 = 0.66) and T2 (pE1 = 0.04; pE2 = 0.008, dE1 = 0.37; dE2 = 0.64) than the 'See One, Do One' group. The intragroup comparison showed a significant (pE1 = 0.0002; pE2 = 0.06, dE1 = 1.07; dE2 = 0.50) increase in clinical examination skills in the 'See One, Do One' group, while the 'Mental Training' group maintained an already high level of clinical examination skills between T1 and T2. DISCUSSION: 'Mental Training' is an efficient tool to teach and maintain basic clinical skills. In this study 'Mental Training' was shown to be superior to the commonly used 'See One, Do One' approach in learning how to perform a structured facial examination and should therefore be considered more often to teach physical examination skills.

Screw-retained monolithic zirconia vs. cemented porcelain-fused-to-metal implant crowns: a prospective randomized clinical trial in split-mouth design.

OBJECTIVES: The objective of the present study was to compare the clinical performance of screw-retained, monolithic, zirconia, and cemented porcelain-fused-to-metal (PFM) implant crowns. MATERIALS AND METHODS: In a prospective, randomized, clinical, split-mouth trial, 22 patients' bilateral premolar or molar single-gap were restored with either screw-retained (test group) or cemented supraconstruction (control group). Clinical parameters, soft-tissue health, crestal bone-level changes, technical complications, and patient's subjective feelings were recorded during a follow-up period of 12 months. RESULTS: No implant was lost during the follow-up period. Of the crowns, 4.5% (test) and 9.1% (control) showed bleeding on probing (P = 1.000), and plaque was visible in 13.6% (test) and 27.3% (control) of the crowns (P = 0.240). Changes in bone crest level seemed to have no correlation with the restoration method (P = 0.77/0.79). Technical failures were observed in three restorations of the test and four of the control group. Evaluation of patients' satisfaction revealed high acceptance regarding fit, esthetics, and chewing effectiveness in both groups. CONCLUSION: Over a 12-month follow-up, screw-retained and cemented crowns could show comparable clinical and radiological results regarding soft tissue health, marginal bone level, and patient satisfaction. Duration of treatment alone was significantly shorter in screw-retained crowns. CLINICAL RELEVANCE: Prosthetic retention methods are related with the occurrence of complications, such as peri-implantitis. However, scientific valuable data that proof superiority of a specific retention technique are rare. In single-gap implants, screw retention and cementation seemed to achieved comparable results.

Prefabricated taper crowns for the retention of implant superstructures: Three-year results of a prospective clinical trial.

STATEMENT OF PROBLEM: Nonrigid retainer systems for removable implant superstructures are associated with negative effects such as rocking and increased load on the denture base. Rigid retainer systems such as telescopic crowns reduce these negative effects, but their fabrication demands highly skilled dental technicians and is therefore expensive. Whether a protocol with prefabricated retainers will reduce production time is unclear. PURPOSE: The purpose of this prospective clinical trial was to evaluate a prefabricated telescopic retainer and a treatment protocol including the intraoral luting of a framework. MATERIAL AND METHODS: A total of 23 participants (15 women and 8 men with a mean age of 61.6 ±2.9 years) were included. After 3 dropouts, 21 removable dentures (9 mandibular and 12 maxillary) retained by 91 delayed loaded Ankylos implants were investigated. All implants were restored with prefabricated conically shaped abutments (SynCone-abutment). The prefabricated corresponding cone matrix was assembled intraorally into a metal frame with autopolymerizing resin. After a loading period of 3 years, a follow-up examination investigated the fit of the framework, the prosthetic aftercare, the technical failures, and the retention force. A questionnaire was used to evaluate participant satisfaction. In addition, laboratory fabrication time and costs were compared with those of individually fabricated restorations. RESULTS: One mandibular implant was lost after 25 months (survival rate, 98.9%). The removable dentures showed no apparent rocking and minimal prosthetic maintenance during the 36-month trial. No dentures required relining. The retention force was scored as good in 17 participants and high (with 6 implants in the maxilla) and low (with 2 implants in the mandible) in 2 participants each. No technical failures occurred. An assessment of laboratory fabrication time and costs revealed reduced time and costs. Patient satisfaction was significantly increased (P<.001) over the entire observation time. CONCLUSIONS: The SynCone retainer presented a time- and cost-efficient treatment option with sufficient long-term retention for removable dentures and high patient satisfaction. Mandibular prostheses restored with 2 implants had limited success.

Allogeneic bone block for challenging augmentation-a clinical, histological, and histomorphometrical investigation of tissue reaction and new bone formation.

OBJECTIVES: The aim of the present study was the histological investigation of an allogeneic spongious bone block for horizontal and vertical ridge augmentation in humans. The amount of new bone, soft tissue, and residual bone substitute were histomorphometrically assessed after a mean healing period of 6 months. MATERIALS AND METHODS: Fourteen patients received augmentation with an allogeneic spongious bone block (Tutobone®, Tutogen Medical, Neunkirchen, Germany). After 6 months of healing, 28 implants were placed with simultaneous harvesting of bone biopsies for histological and histomorphometrical analysis. Moreover, samples from the bone blocks were collected as blanks and analyzed histologically. The formation of new bone, connective tissue, and remaining bone substitute material as well as vascularization and formation of multinucleated giant cells (MNCGs) within the augmentation bed were analyzed. RESULTS: New bone formation could be observed primarily in close proximity to the bone block. Histomorphometrical analyses showed 18.65 ± 12.20% newly formed bone, 25.93 ± 12.36% allogeneic spongious bone block, and 53.45 ± 10.34% connective tissue. MNCGs were observed on the biomaterial surface. Furthermore, organic residues were evident, as donor-related cellular remnants within the osteocyte lacunae were found in the blank bone blocks and in the analyzed biopsies. CONCLUSION: Despite the presence of donor-related organic remnants, the bone block shows the ability to serve as a scaffold for new bone formation. Within the limits of the present study, the detect organic remnants seemed not to affect the bone formation or influence the host in the long term. CLINICAL RELEVANCE: Clinicians have to make a conscious choice of the applied biomaterials with regard to their components and structure to support tissue regeneration and maintain patient safety.

Individualized Titanium Mesh Combined With Platelet-Rich Fibrin and Deproteinized Bovine Bone: A New Approach for Challenging Augmentation.

Autologous bone transfer is regarded as the gold standard for ridge augmentation before dental implantation, especially in severe bony defects caused by tumor resection or atrophy. In addition to the advantages of autologous bone, transplantation has several disadvantages, such as secondary operation, increased morbidity and pain. The present study reports, for the first time, a combination of a xenogeneic bone substitute (BO) with platelet-rich fibrin (PRF), which is a fully autologous blood concentrate derived from the patient's own peripheral blood by centrifugation. Solid A-PRF+ and liquid i-PRF together with an individualized 3-D planned titanium mesh were used for reconstruction of a severe tumor-related bony defect within the mandible of a former head and neck cancer patient. The BO enriched with regenerative components from PRF allowed the reconstruction of the mandibular resective defect under the 3-D mesh without autologous bone transplantation. Complete rehabilitation and restoration of the patient's oral function were achieved. Histological analysis of extracted bone biopsies confirmed that the new bone within the augmented region originated from the residual bone. Within the limitations of the presented case, the applied concept appears to be a promising approach to increase the regenerative capacity of a bone substitute material, as well as decrease the demand for autologous bone transplantation, even in cases in which autologous bone is considered the golden standard. PRF can be considered a reliable source for increasing the biological capacities of bone substitute materials.

Fifteen Years of Platelet Rich Fibrin in Dentistry and Oromaxillofacial Surgery: How High is the Level of Scientific Evidence?

Platelet-rich fibrin is a blood concentrate system used for soft tissue and bone tissue regeneration. In the last decade, platelet rich fibrin (PRF) has been widely used in different indication fields, particularly in oral and maxillofacial surgery. This review investigates the level of scientific evidence of published articles related to the use of PRF for bone and soft tissue regeneration in dentistry and maxillofacial surgery. An electronic literature research using the biomedical search engine "National Library of Medicine" (PubMed-MEDLINE) was performed in May 2017. A total of 392 articles were found, 72 of which were classified for each indication field. When comparing PRF with biomaterials vs biomaterial alone in sinus lift (5 studies; IIa), no statistically significant differences were detected. Socket preservation and ridge augmentation using PRF significantly enhanced new bone formation compared to healing without PRF (7 studies Ib, IIa, IIb). Reepithelialization and bone regeneration was achieved in 96 of 101 patients diagnosed with medication-related osteonecrosis of the jaw (5 studies, III). In periodontology, PRF alone (6 studies; Ib, IIa, IIb) or its combination with biomaterials (6 studies; Ib, IIa, IIb) significantly improved the pocket depth and attachment loss compared to a treatment without PRF. Over 70% of the patients were part of studies with a high level of scientific evidence (randomized and controlled prospective studies). This published evidence (38 articles), with a high scientific level, showed that PRF is a beneficial tool that significantly improves bone and soft tissue regeneration. However, the clinical community requires a standardization of PRF protocols to further examine the benefit of PRF in bone and soft tissue regeneration in reproducible studies, with a higher scientific level of evidence.

Expansion of the peri-implant attached gingiva with a three-dimensional collagen matrix in head and neck cancer patients-results from a prospective clinical and histological study.

OBJECTIVES: Attached peri-implant gingiva has proven to have an influence on the long-term stability of dental implants. In patients with head and neck cancer, a functional peri-implant gingiva is even more of critical importance. The aim of the presented prospective study was to investigate a three-dimensional xenogeneic collagen matrix for augmentation around dental implants in patients with former head and neck cancer. MATERIAL AND METHODS: Eight patients presenting with insufficient peri-implant gingiva underwent vestibuloplasty on 51 implants using a xenogeneic collagen matrix. The clinical performance and the shrinking tendency of the matrix were analyzed in a cohort study. Furthermore, eight biopsies from the augmented regions were examined histologically to determine the biomaterial-related tissue reaction. RESULTS: Initially after vestibuloplasty, a mean width of attached gingiva of 4.4 ± 0.94 mm could be achieved. At clinical follow up investigation 6 months after vestibuloplasty, a mean width of 3.9 ± 0.65 mm attached peri-implant gingiva with a mean shrinking tendency of 14 % could be detected. Histological analysis of the biopsies revealed a well integrated collagen22 matrix covered with epithelium. Within the compact layer, mononuclear cells were observed only, while the spongious layer was infiltrated with a cell-rich connective tissue. CONCLUSION: Within its limits, the presented study revealed that the investigated collagen matrix is suitable to enlarge the peri-implant attached gingiva in head and neck cancer patients without adverse reactions or a multinucleated giant cell-triggered tissue reaction. CLINICAL RELEVANCE: The application of the investigated three-dimensional collagen matrix in vestibuloplasty achieved a sufficient amount of peri-implant attached gingiva in head and neck cancer patients. The favorable tissue reaction and the low shrinking tendency make the collagen matrix a promising alternative to autologous tissue grafts.

Nanocrystalline hydroxyapatite-based material already contributes to implant stability after 3 months: a clinical and radiologic 3-year follow-up investigation.

The present study reports on a 3-year clinical and radiologic follow-up investigation of dental implants placed 3 and 6 months after sinus augmentation in 14 patients. Augmentation was performed with a synthetic bone substitute material composed of nanocrystalline hydroxyapatite. The aim of the study was to determine how the integration period of the bone substitute material, that is, 3 months or 6 months, influences implant integration within the patient's upper jaw. Therefore, the following clinical and radiologic parameters were investigated: implant being in situ; Periotest value; and presence of peri-implant osteolysis, bleeding on probing, plaque, and soft tissue recession around the implants. At the follow-up investigation 3 years after placement, 23 of 24 implants were in situ and suitable for prosthetic rehabilitation. No implants in either study group were mobile or showed peri-implant osteolysis. Only a few implants showed plaque or soft tissue variations. Within its limits, the present study showed comparable clinical performance of dental implants placed 3 months after sinus floor augmentation to implants placed 6 months after augmentation. The results of all investigated parameters were in accordance with results found in the literature. It can be concluded that augmentation with the applied synthetic bone substitute material already forms a sufficient implantation bed 3 months after augmentation, which enables long-term, stable, implant-retained restoration. These findings might contribute to a reduced healing time after augmentation, which would be favorable for patients and clinicians.

Advanced platelet-rich fibrin: a new concept for cell-based tissue engineering by means of inflammatory cells.

Choukroun's platelet-rich fibrin (PRF) is obtained from blood without adding anticoagulants. In this study, protocols for standard platelet-rich fibrin (S-PRF) (2700 rpm, 12 minutes) and advanced platelet-rich fibrin (A-PRF) (1500 rpm, 14 minutes) were compared to establish by histological cell detection and histomorphometrical measurement of cell distribution the effects of the centrifugal force (speed and time) on the distribution of cells relevant for wound healing and tissue regeneration. Immunohistochemistry for monocytes, T and B -lymphocytes, neutrophilic granulocytes, CD34-positive stem cells, and platelets was performed on clots produced from four different human donors. Platelets were detected throughout the clot in both groups, although in the A-PRF group, more platelets were found in the distal part, away from the buffy coat (BC). T- and B-lymphocytes, stem cells, and monocytes were detected in the surroundings of the BC in both groups. Decreasing the rpm while increasing the centrifugation time in the A-PRF group gave an enhanced presence of neutrophilic granulocytes in the distal part of the clot. In the S-PRF group, neutrophils were found mostly at the red blood cell (RBC)-BC interface. Neutrophilic granulocytes contribute to monocyte differentiation into macrophages. Accordingly, a higher presence of these cells might be able to influence the differentiation of host macrophages and macrophages within the clot after implantation. Thus, A-PRF might influence bone and soft tissue regeneration, especially through the presence of monocytes/macrophages and their growth factors. The relevance and feasibility of this tissue-engineering concept have to be proven through in vivo studies.

Multistate switching of scanning tunnelling microscopy machined polyoxovanadate-dysprosium-phthalocyanine nanopatterns on graphite.

We demonstrate the first formation of stable, multistate switchable monolayers of polyoxometalates (POMs), which can be electronically triggered to higher charged states with increased conductance in the current-voltage profile at room temperature. These responsive two-dimensional monolayers are based on a fully oxidised dodecavanadate cage (POV12) equipped with Dy(III)-doped phthalocyanine (Pc) macrocycles adopting the face-on orientation on highly oriented pyrolytic graphite (HOPG). The layers can be lithographically processed by the tip of a scanning tunnelling microscope (STM) to machine patterns with diameters ranging from 30 to 150 nm2.

Synthesis and structures of cobalt-expanded zirconium- and cerium-oxo clusters as precursors for mixed-metal oxide thin films.

Transforming current complementary metal-oxide-semiconductor (CMOS) technology to fabricate memory chips and microprocessors into environmentally friendlier electronics requires the development of new approaches to resource- and energy-efficient electron transport and switching materials. Metal and multi-metal oxide layers play a key role in high-end technical applications. However, these layers are commonly produced through high-energy and high-temperature procedures. Herein, we demonstrate our first attempts to obtain stimuli-responsive mixed-metal oxide thin films from solution-processed molecular precursors under milder conditions. The molecular compounds of interest were prepared by one-pot reactions of a CoII carboxylate complex, triethylamine (Et3N), N-butyldiethanolamine (H2bda), and a hexanuclear complex [Ce6O4(OH)4(piv)12] (Hpiv = pivalic acid) or [Zr6O4(OH)4(ib)12(H2O)]·3Hib (Hib = isobutyric acid) in acetonitrile solution. The resulting charge-neutral, heterometallic coordination compounds display a ligand-supported pentanuclear {CeIV3CoIII2} core (in 1) and a dodecanuclear {ZrIV6CoII6} core (in 2), exhibiting thermal stability up to ca. 100 °C in air. Compound 2 was deposited and analyzed on Au(111) and SiO2/Si(100) surfaces to explore its potential as a single-molecule precursor for the preparation of atomically precise, complex mixed-metal oxide thin films. The adsorption characteristics of it demonstrate the ability to form stable agglomerates on the investigated surfaces.

Long-Term Peri-Implant Health and Papilla Formation at Healed Sites by Chairside Provisionalization of Single-Tooth Implants: A Prospective Case Series.

PURPOSE: Several procedures are performed to achieve optimal esthetic results in single-tooth implants. However, there is discordance regarding the potential benefit and risks of immediate implant loading/provisionalization. The aim of this prospective case series is to investigate the effect of immediate provisionalization of single-tooth implants at healed sites for periimplant soft-tissue conditions, focusing on papilla formation around single implants. MATERIALS AND METHODS: Twelve patients received a total of 12 implants in the incisor, canine or premolar region of the upper and lower jaw at healed sites with immediate chair-side provisionalization. Four months later, the temporary crown was replaced by the permanent crown. After 40±13.1 months, clinical follow-up was conducted, assessing Probing pocket depth (PPD); Bleeding on Probing(BoP); Mucosal recession (MR) and Width of Keratinized Mucosa (KM). Papilla index (PI) was determined immediately after implant placement (baseline), before removing the temporary crown (t1), 4 weeks after insertion of the definitive crown (t2) and at the final follow-up examination (t3) to evaluate papilla formation and its change over time. RESULTS: None of the implants were lost. The mean PPD was 2.5±0.39 mm, BoP of 25% and 3.5 mm of KM were observed at the final follow-up. No implants showed MR. PI increased in all patients from 1.5±0.45 at baseline to 2.4±0.56 at t1, 2.6±0.47 at t2 and 3.02.6±0 at t3. The increase in PI between t0 and each individual timepoint from t1-t3 showed statistical significance. CONCLUSION: The present results indicate the suitability and benefit of immediate provisionalization to achieve favorable peri-implant soft-tissue conditions and papilla formation.

Clinical performance of a newly developed two-piece zirconia implant system in the maxilla: A prospective multicentre study.

PURPOSE: To assess the clinical performance of a two-piece zirconia implant system (PURE Ceramic Implants, Straumann, Basel, Switzerland) in the maxilla after a follow-up period of more than 1 year. MATERIALS AND METHODS: A total of 19 patients in three centres received 24 single-tooth implants in the maxilla. The implants were restored after a mean healing period of 7.1 ± 0.4 months (range 7 to 9 months). Implant survival, implant success, Plaque Index, probing pocket depth, bleeding on probing, mucosal recession/creeping attachment, width of keratinised mucosa, papilla index and pink aesthetic score were evaluated after prosthetic loading (T0), after 6 months (T1) and at the final follow-up (T2, mean 15.0 ± 2.1 months, range 12 to 19 months). RESULTS: All implants survived and were suitable for retaining prostheses. Low values were recorded for Plaque Index (0.38 ± 0.68) and probing pocket depth (2.49 ± 0.49 mm). Bleeding on probing increased significantly from T0 (21.7%) to T1 (50.0%) (P = 0.0342) and then remained stable (50.0% at T2). No recession was detected around any of the implants. A statistically significant increase in attachment level was observed from T0 to T2 (0.79 ± 0.88 mm; P = 0.0196). A papilla index of 2.27 ± 0.81 and pink aesthetic score of 11.67 ± 1.60 at T2 indicated a completely satisfying aesthetic result. CONCLUSION: Within the limitations of the present study, the two-piece zirconia implant system investigated achieved fully satisfying functional and aesthetic results.

Biomaterial-based bone regeneration and soft tissue management of the individualized 3D-titanium mesh: An alternative concept to autologous transplantation and flap mobilization.

Three-dimensional augmentation in severely atrophic bone and after cancer resection is a challenging clinical indication that is mostly solved using autologous bone transplantation. The development of the digital technique along with the additive manufacturing and three-dimensional (3D) printing opened new avenues for reconstructive oral and maxillofacial surgery. Therefore, patient-specific titanium mesh is a novel means of stabilizing the augmentation region using particulate bone substitute materials (BSMs) combined with autologous bone as a minimally invasive concept. However, dehiscence is a frequently reported complication in this field. Therefore, the aim of the present case series was to introduce a biomaterial-based regenerative concept in terms of exposed open healing to overcome the dehiscence related to 3D-titanium meshes. Additionally, this case series presents a novel protocol using a combination of xenogeneic BSMs with an autologous blood concentrate system (platelet-rich fibrin [PRF]) and collagen matrices without any autologous transplantation. Seven patients with alveolar ridge atrophy with different etiologies (cancer resection, severe atrophy after tooth loss, aplasia, trauma, implant infections) were treated using the open-healing concept. Therefore, after 3D augmentation using the described biomaterials, the flap margins were approximated, and the gap between the flap margins was bridged using a collagen matrix loaded with liquid PRF that was then covered by either a PTFE-based membrane or sterile latex. No periosteum splitting was performed at any time point. After a healing period of 4-8 months, all patients received dental implants as virtually planned. Bone biopsies were performed during dental insertion for histological evaluation. The augmentation area displayed a vital and well-vascularized newly formed bone that incorporated the BSM granules to build a hybrid bone. Additionally, open healing resulted in newly formed soft tissue without any signs of scar formation or fibrosis. The regenerated soft tissue was used to build a new flap during implant insertion and showed good functional and aesthetic results after implant insertion. The open-healing concept of the regeneration of the soft tissue along with bone tissue to regenerate a harmonic implantation bed is a minimally invasive intervention without periosteum splitting or large flap mobilization. However, further controlled clinical studies are needed to evaluate this concept in a larger patient cohort to outline the potential clinical benefit.

Prospective controlled clinical study investigating long-term clinical parameters, patient satisfaction, and microbial contamination of zirconia implants.

BACKGROUND: Dental implants made of zirconia ceramics experienced a renaissance in the past years. However, there is still a lack in reliable long-term clinical data. PURPOSE: Aim of the present prospective clinical study was to analyze the dental implants made from zirconia, regarding their clinical performance compared to natural teeth (control). MATERIALS AND METHODS: Eighty-three zirconia implants in 28 adults were analyzed after 7.8 years of integration. Approximal plaque index (API), sulcus bleeding index (SBI), probing pocket depth (PPD), probing attachment level (PAL), and creeping or recession (CR/REC) of the mucosa/gingiva were analyzed. Changes in the marginal bone level (MBL) have been determined by comparing radiographs recorded immediately after implant placement and at the follow-up investigation. Furthermore, the pink esthetic score (PES), Periotest values (PTV), microbial colonization of the implant/dental sulcus fluid, and patient satisfaction were assessed. RESULTS: The survival rate of zirconia implants was 100%, however one implant presented a profound peri-implantitis, resistant to therapies. No statistical significance was observed between implants and teeth regarding SBI and PAL. Statistical significance was detected regarding API and CR/REC with significantly less plaque accumulation and recession in the study group. Significantly higher values for PPD were obvious in the zirconia implant group. PES of 9 ± 2.7 indicate a rather average esthetic result. Analysis of MBL revealed a mean peri-implant bone resorption of 1.2 mm. Microbial analysis revealed a nonstatistically significant higher colonization of bacteria in the study group, whereas single bacteria species were detected in statistically significant higher amounts. CONCLUSION: The investigated one-piece zirconia dental implants presented favorable long-term clinical results, comparable to natural teeth (SBI and PAL), and, regarding adhesion of plaque and creeping attachment (CR/REC), even superior. The microbial investigation revealed a shift in peri-implant colonization around zirconia implants over years, mainly without clinical effect on peri-implantitis.

Short implants in the posterior maxilla to avoid sinus augmentation procedure: 5-year results from a retrospective cohort study.

BACKGROUND: Short implants present a promising approach for patients with advanced atrophy to avoid augmentative procedures. However, concerns about increased biological and technical complications due to an unfavorable implant-crown ratio are still present. PURPOSE: The aim of the present retrospective study was to evaluate whether a reduced implant length has any impact on implant success and peri-implant hard and soft tissue health in implants placed in the posterior maxilla to avoid sinus augmentation procedures. MATERIALS AND METHODS: Fourteen patients received a total of 30 implants of 7-mm length in the posterior maxilla. Implants with a mean loading period of 5 years (range 2-7 years) were followed up clinically and radiologically, with a focus on the peri-implant soft tissue parameters probing pocket depth (PPD), bleeding on probing (BoP), and the stability of the marginal peri-implant bone level. RESULTS: None of the implants were lost, and no technical failures occurred. A mean PPD of 2.5 mm, a mean BoP of 13.3%, and a mean marginal bone loss (MBL) of 0.5 mm indicate healthy peri-implant hard and soft tissue conditions without signs of peri-implantitis. DISCUSSION: The present results indicate the suitability of implants of 7-mm length to replace missing teeth in the posterior maxilla. An unfavorable implant-crown ratio or reduced bone-implant contact length seems to have no negative influence on midterm implant success or on peri-implant hard and soft tissue health.

All-ceramic versus titanium-based implant supported restorations: Preliminary 12-months results from a randomized controlled trial.

PURPOSE: The aim of the present randomized controlled study was to compare prefabricated all-ceramic, anatomically shaped healing abutments followed by all-ceramic abutments and all-ceramic crowns and prefabricated standard-shaped (round-diameter) titanium healing abutments followed by final titanium abutments restored with porcelain-fused-to-metal (PFM) implant crowns in the premolar and molar regions. MATERIALS AND METHODS: Forty-two patients received single implants restored either by all-ceramic restorations (test group, healing abutment, final abutment, and crown all made of zirconia) or conventional titanium-based restorations. Immediately after prosthetic incorporation and after 12 months of loading, implant survival, technical complications, bone loss, sulcus fluid flow rate (SFFR) as well as plaque index (PI) and implant stability (Periotest) were analyzed clinically and radiologically. RESULTS: After 12 months of loading, an implant and prosthetic survival rate of 100% was observed. Minor prosthetic complications such as chipping of ceramic veneering occurred in both groups. No statistical significant differences were observed between both groups with only a minimum of bone loss, SFFR, and PI. CONCLUSION: All-ceramic implant prostheses including a prefabricated anatomically shaped healing abutment achieved comparable results to titanium-based restorations in the posterior region. However, observational results indicate a benefit as shaping the peri-implant soft-tissue with successive provisional devices and subsequent compression of the soft tissue can be avoided.