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The aim of the present study was to compare the survival, stability, and complications of immediately loaded implants placed in postextraction sockets and healed sites.Over a 2-year period, all patients presenting with partial or complete edentulism of the maxilla and/or mandible (healed site group, at least 4 months of healing after tooth extraction) or in need of replacement of nonrecoverable failing teeth (postextraction group) were considered for inclusion in this study. Tapered implants featuring a nanostructured calcium-incorporated surface were placed and loaded immediately. The prosthetic restorations comprised single crowns, fixed partial dentures, and fixed full arches. Primary outcomes were implant survival, stability, and complications. Implant stability was assessed at placement and at each follow-up evaluation (1 week, 3 months, and 1 year after placement): implants with an insertion torque (IT)45 N·cm and/or with an implant stability quotient (ISQ)70 were considered failed for immediate loading. A statistical analysis was performed.Thirty implants were placed in postextraction sockets of 17 patients, and 32 implants were placed in healed sites of 22 patients. There were no statistically significant differences in ISQ values between the 2 groups, at each assessment. In total, 60 implants (96.8%) had an IT ≥45 and an ISQ ≥70 at placement and at each follow-up control: all these implants were successfully loaded. Only 2 implants (1 in a postextraction socket and 1 in a healed site, 3.2%) could not achieve an IT ≥45 N·cm and/or an ISQ ≥70 at placement or over time: accordingly, these were considered failed for stability, as they could not be subjected to immediate loading. One of these 2 implants, in a healed site of a posterior maxilla, had to be removed, yielding an overall 1-year implant survival rate of 98.4%. No complications were reported. No significant differences were reported between the 2 groups with respect to implant failures and complications.Immediately loaded implants placed in postextraction sockets and healed sites had similar high survival and stability, with no reported complications. Further long-term studies on larger samples of patients are needed to confirm these results.

In the anterior regions, the resorption of the buccal bone after tooth extraction leads to a contraction of the overlying soft tissues, resulting in an esthetic problem, particularly with immediate implant placement. In the socket shield technique, the buccal root section of the tooth is maintained, to preserve the buccal bone for immediate implant placement. The aim of this prospective study was to investigate the survival, stability, and complication rates of implants placed using a "modified" socket shield technique.Over a 2-year period, all patients referred to a dental clinic for treatment with oral implants were considered for inclusion in this study. Inclusion criteria were healthy adult patients who presented nonrestorable single teeth with intact buccal periodontal tissues in the anterior regions of both jaws. Exclusion criteria were teeth with present/past periodontal disease, vertical root fractures on the buccal aspect, horizontal fractures below bone level, and external/internal resorptions. The buccal portion of the root was retained to prevent the resorption of the buccal bone; the shield was 1.5 mm thick with the most coronal portion at the bone crest level. All patients then underwent immediate implants. In the patient with a gap between the implant and shield, no graft material was placed. All implants were immediately restored with single crowns and followed for 1 year. The main outcomes were implant survival, stability, and complications.Thirty patients (15 males, 15 females; mean age was 48.2 ± 15.0 years) were enrolled in the study and installed with 40 immediate implants. After 1 year, all implants were functioning, for a survival rate of 100%; excellent implant stability was reported (mean implant stability quotient at placement: 72.9 ± 5.9; after 1 year: 74.6 ± 2.7). No biologic complications were reported, and the incidence of prosthetic complications was low (2.5%).The "modified" socket shield technique seems to be a successful procedure when combined with immediate implant placement, because the root fragment does not interfere with osseointegration and may be beneficial for the esthetics, protecting the buccal bone from resorption.

Phosphinodiselenoic acid esters are synthesized from the reaction of chlorodiphenylphosphine and aryl- or alkyl-magnesium bromide in the presence of selenium powder. They are employed as RAFT agents in thermally initiated, styrene polymerization. The phosphinodiselenoic acid esters 6a and 6b showed some degree of control over the radical polymerization of styrene.

Objective. To evaluate horizontal bone gain and implant survival and complication rates in patients treated with titanium meshes placed simultaneously with dental implants and fixed over them. Methods. Twenty-five patients treated with 40 implants and simultaneous guided bone regeneration with titanium meshes (i–Gen®, MegaGen, Gyeongbuk, Republic of Korea) were selected for inclusion in the present retrospective multicenter study. Primary outcomes were horizontal bone gain and implant survival; secondary outcomes were biological and prosthetic complications. Results. After the removal of titanium meshes, the CBCT evaluation revealed a mean horizontal bone gain of 3.67 mm (±0.89). The most frequent complications were mild postoperative edema (12/25 patients: 48%) and discomfort after surgery (10/25 patients: 40%); these complications were resolved within one week. Titanium mesh exposure occurred in 6 patients (6/25 : 24%): one of these suffered partial loss of the graft and another experienced complete graft loss and implant failure. An implant survival rate of 97.5% (implant-based) and a peri-implant marginal bone loss of 0.43 mm (±0.15) were recorded after 1 year. Conclusions. The horizontal ridge reconstruction with titanium meshes placed simultaneously with dental implants achieved predictable satisfactory results. Prospective randomized controlled trials on a larger sample of patients are required to validate these positive outcomes.

This study aims to integrate formal and non-formal grammar (func- tional grammar and cognitive grammar) in order to draw a better comprehen- sion of English complement clauses. They have been analyzed displaying dis- cordant arguments depending on the investigational disciplines. This study has been able to systemize them into a consistent and advantageous theory by se- curing syntactic objectivity with formal grammar, cognitive intuition with cog- nitive grammar and semantic differences with functional grammar. It is desira- ble to investigate syntactic phenomena from a complementary point of view.

The controlled free radical polymerization of styrene initiated with benzoyl peroxide (BPO) in the presence of 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (4-oxo-TEMPO) as well as 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl (4-acetamido-TEMPO) at 135°C was studied. The obtained results were compared with those of the 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) controlled free radical polymerization of styrene. Up to a nitroxide/BPO molar ratio of 1.5:1, the conversions in the 4-oxo-TEMPO/BPO-system are higher than the conversions in the other systems. The conversion in the 4-acetamido-TEMPO/BPO-system is lower than that in the 4-oxo-TEMPO/BPO-system, but higher than the conversion in the TEMPO/ BPO-system under the same reaction conditions. The shortest induction periods were observed in the 4-oxo-TEMPO/BPO-system, while the longest induction periods were observed in the TEMPO/BPO-system. Except in the lower region of nitroxide/BPO molar ratio (1:1), the number-average molecular weight (M n ) increases linearly with conversion in all systems. Interestingly, the growth of the molecular weight (M n ) is independent of the nitroxide/BPO molar ratio in the 4-oxo-TEMPO-controlled free radical polymerization of styrene, while M n in the 4-acetamido-TEMPO/BPO- and the TEMPO/BPO-system decreases with increasing nitroxide/BPO molar ratio. The polydispersities (M w /M n ) of the obtained polymers are below 1.4 except those of low nitroxide/BPO molar ratios, which indicates a controlled polymerization process.

Poly(styrene-co-N-vinylcarbazole) copolymers with controlled molecular weights and narrow polydispersities were synthesized by N-oxyl-controlled free radical copolymerization using benzoyl peroxide as initiator and 2,2,6,6-tetramethylpiperidine-N-oxyl as terminating agent. To improve the low polymerization rates, the radical initiator dicumyl peroxide (DCP) was introduced and its effects on the polymerization rate, the molecular weight and the polydispersity were studied. It was demonstrated that the introduction of DCP leads to a significant enhancement of the polymerization rate and that copolymers with high N-vinylcarbazole contents as well as N-vinylcarbazole homopolymer can be obtained. The enhancement of the polymerization rate corresponds to a decrease in the number of chain breaking reactions which leads to polymers with lower polydispersities compared with those polymerized at the same monomer conversion without DCP. This could be proved via comparative chain-extension experiments with styrene leading to poly(styrene-co-N-vinylcarbazole)-block-poly(styrene) diblock copolymers. Poly(Styrol-co-N-Vinylcarbazol)-Copolymere mit kontrollierter Molmasse und enger Polydispersitat wurden durch N-Oxyl-kontrollierte radikalische Polymerisation hergestellt. Als Initiator wurde Dibenzoylperoxid und als Terminator 2,2,6,6-Tetramethylpiperidin-N-oxyl verwendet. Um die geringen Polymerisationsgeschwindigkeiten zu beschleunigen, wurde der Einflus eines zusatzlich hinzugefugten Initiators, Dicumylperoxid (DCP), auf die Polymerisationsgeschwindigkeit, die Molmassen und die Polydispersitat der hergestellten Polymere diskutiert. Mit Hilfe von DCP kann die Polymerisationsgeschwindigkeit signifikant erhoht werden, so das auch Copolymere mit sehr hohem N-Vinylcarbazol-Gehalt bis hin zum Homo-N-Vinylcarbazol zuganglich werden. Die Beschleunigung der Polymerisationsgeschwindigkeit reduziert gleichzeitig die Anzahl der auftretenden Abbruchreaktionen, so das die mit DCP synthetisierten Copolymeren eine geringere Polydispersitat besitzen als bei gleichem Monomerumsatz entnommene Produkte, die ohne DCP synthetisiert worden sind. Dies konnte mit Hilfe von Kettenverlangerungsexperimenten verifiziert werden, bei denen Styrol an unterschiedlich hergestellte Poly(Styrol-co-N-Vinylcarbazol)-Copolymere polymerisiert worden ist.

The bulk polymerization of styrene at 125°C was studied using a [BPO-polystyrene-(4-acetamido-TEMPO)] macroinitiator synthesized by a styrene polymerization in the presence of 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl (4-acetamido-TEMPO) and benzoyl peroxide (BPO). The rates of polymerization were independent of the initial macroinitiator concentration and they were very similar to that for the thermal autopolymerization of styrene. Additionally, different types of N-oxyls did not have any effect on the polymerization rate. The number-average molecular weights (Mn) of the obtained polymers agreed very well with theoretical predictions, deviations were observed only at low macroinitiator concentrations. Increasing macroinitiator concentrations resulted in lower magnitudes of the growing molecular weights and reduced polydispersities (Mw/Mn) at the initial stage of the polymerization. The concentration of the polymer chains was calculated, and it was recognized that the concentration of polymer chains increased during the polymerization as a result of an additional radical formation due to the thermal self-initiation of styrene. This thermal self-initiation could be proved qualitatively by the addition of N-oxyl to a macroinitiator polymerization system. Ausgehend von [BPO-Polystyrol-(4-Acetamido-TEMPO)]-Makroinitiatoren wurde die Substanzpolymerisation von Styrol bei 125°C untersucht. Die Polymerisationsgeschwindigkeit war unabhangig von der eingesetzten Makroinitiator-Konzentration und stimmte im Rahmen der Mesgenauigkeit mit der der thermisch initiierten Autopolymerisation von Styrol uberein. Bezuglich der Art des verwendeten N-Oxyls wurde kein Einflus auf die Polymerisationsgeschwindigkeit festgestellt. Die mit Gelpermeationschromatographie (GPC) ermittelten Molmassen stimmten gut mit den theoretisch geschatzten Molmassen uberein, Abweichungen liesen sich nur bei geringen Makroinitiator-Konzentrationen beobachten. Zunehmende Makroinitiator-Konzentrationen resultierten in einer Reduktion der Molmassenzunahme sowie der Polydispersitat, wobei eine Beeinflussung der Polydispersitat insbesondere in der Anfangsphase der Polymerisation beobachtet wurde. Durch Berechnung von Kettenkonzentrationen liesen sich eindeutig Radikal-Neubildungen durch die thermische Styrol-Selbstinitiierung feststellen. Zusatzlich wurde diese Selbstinitiierung durch spezielle Reaktionsfuhrung mit N-Oxyl-Zudosierung qualitativ nachgewiesen.

Through comparative studies on the controlled thermally initiated radical polymerization of styrene in the presence of N-oxyls, the effect of the type of the N-oxyls (2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (OH-TEMPO), 4-oxo-2,2,6,6-tetranicthylpiperidine-N-oxyl (oxo-TEMPO) and 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl (acetamido-TEMPO)), as well as the concentration of the N-oxyls (3-20 mmol L-') are discussed. The radical formation proceeds exclusively through the thermal initiation of styrene, i.e. without using any initiator. It is observed, that the thermal self-initiation of styrene increases the radical yield remarkably with the N-oxyls concentration, independent of the type of the N-oxyl. The concentration-dependent side reactions of substituted N-oxyls are remarkably more pronounced than those of unsubstituted N-oxyl. This leads to the reduction of the overall rate of polymerization (v br ) as compared to TEMPO (v br = v br (thermal polymerization)) with respect to the concentration, but independent of the type of substituents.

A. xylosoxidans는 면역저하 상태에서 기회감염을 일으키며 호흡기 감염은 매우 드문 균으로 알려져 있다. 저자들은 최근 면역저하가 없는 환자에서 발생한 A. xylosoxidans에 의한 호흡기 감염증을 2예 경험하였기에 문헌 고찰과 함께 보고한다. 본 증례를 통해 정상면역을 가진 환자에서 A. xylosoxidans가 호흡기 감염의 원인일 수 있으며, 이와 같은 경우 세균학적 검사결과에 따른 적절한 치료가 필수적이라는 것을 경험하였다.