Alveolar ridge preservation procedures have been shown to significantly reduce the loss of ridge dimension of an extraction socket. As of yet, none of the alveolar ridge preservation techniques have been proven totally effective in preserving ridge morphology. The Periosteal Inhibition technique for alveolar ridge preservation involves placing a high-density polytetrafluoroethylene (d-PTFE) membrane between the periosteum and the buccal bone plate of an extraction socket. The authors hypothesize that the nonresorbable d-PTFE membrane, because of its much smaller pore diameter as compared to the size of the osteoclast precursor cells, inhibits the migration of the osteoclast precursor cells from the periosteum to the bony surface and, subsequently, their fusion to form osteoclasts. As a result, osteolytic activity on the outer surface of the socket is inhibited. The Periosteal Inhibition technique for alveolar ridge preservation is presented along with immediate implant treatment results using this treatment concept. The resulting stable ridge dimensions in these cases demonstrate a possibility that the d-PTFE membrane may effectively prevent modeling of the extraction socket by inhibiting the formation of osteoclasts on the outer bony surface.

Objectives: The present preference clinical trial compared the long-term outcome of acellular dermal matrix allograft (ADMA) versus autogenous connective tissue graft (CTG) in the treatment of gingival recessions. Method and materials: Thirty-nine consecutive patients with 233 Miller Class I and II recessions were treated by one operator (MS) with coronally advanced flaps and in addition either ADMA or CTG harvested from their palate. Clinical parameters were measured by an independent and masked assessor at baseline, 6 months, and 5 years. Results: Thirty-two patients could be recruited for long-term examination (seven dropouts). At 6 months and 5 years, all clinical parameters showed significant improvements in both groups with slightly better but statistically not significant clinical results for CTGs. At 5 years, the CTG group revealed an additional gain of keratinized mucosa width (t6m-0: CTG 1.88 mm, ADMA 1.04 mm, P = .081; and t5y-0: CTG 3.98 mm, ADMA 3.06 mm, P = .01) compared to 6 months, whereas the mean for ADMAs remained stable (intergroup comparison statistically significant, P = .010). In all other parameters in both groups, slight but not statistically significant relapses were detected. Only one minor postoperative complication at one ADMA-treated site occurred. Conclusions: Regarding the long-term results, ADMA could be an alternative treatment option to thicken soft tissue and to cover multiple gingival recessions. If the gain of keratinized mucosa width is considered as a main goal, CTG may have a slight advantage over ADMA. Keywords: acellular dermal matrix, connective tissue, gingival recession, long-term outcome, root coverage

Purpose: To investigate the optimal degree of convergence of the abutment with which the bond strength achieved by the pre-bonding method is comparable with that in direct bonding with a conventional degree of convergence. Materials and Methods: Abutments with 5.5-mm diameter, 5-mm height, 0.5-mm shoulder width, and three kinds of degrees of convergence (2, 4, and 6 degrees) were first designed by digital modeling. Their corresponding inner crowns were also modeled, and a gap of 40 μm was kept between the abutment and the inner crown. Thirty abutments and 30 inner crowns were then lathed out from a titanium plate (10 sets per degree of convergence). Six groups were defined in this study, according to the different degrees of convergence and bonding methods (direct bonding, pre-bonding) (n = 10 sets). The samples handled with direct bonding would be cleaned for reuse in tests with pre-bonding. Temporary cement was used as an adhesive, and the bond strength was tested in each set of samples. The comparison among the results was performed by the Kruskal-Wallis test. Results: The mean values of bond strength with direct bonding methods were 349.39 ± 65.75 N, 316.49 ± 54.22 N, and 277.49 ± 56.96 N, and with pre-bonding methods were 279.35 ± 48.58 N, 227.97 ± 26.72 N, and 154.6 ± 23.03 N, respectively (2, 4, and 6 degrees). No statistical difference was found among the values in direct bonding groups and, in pre-bonding groups, only the comparison between 2 and 6 degrees of convergence showed statistical significance (P = .000). Between different bonding methods, statistical differences were shown in abutments with 4 and 6 degrees of convergence (P = .006, P = .000), respectively. The bond strength with pre-bonding methods and 2 degrees of convergence showed no significant difference from that with direct bonding and 6 degrees of convergence. Conclusion: The bond strength was inversely proportional to the degree of convergence, and the bond strength of pre-bonding was lower than that of direct bonding with the same degree of convergence. When using the pre-bonding method, the bond strength between the abutment and inner crown with 2 degrees of convergence could be comparable with using the direct bonding method and abutments with conventional degrees of convergence. Keywords: bond strength, degrees of convergence, pre-bonding

Eine implantatverankerte Einzelkrone im ästhetisch sichtbaren Bereich, welche mit den benachbarten Strukturen nachhaltig perfekt harmoniert, ist bekanntlich eine große Herausforderung. Die Entscheidung für das Therapieregime einer Sofortimplantation und -versorgung bedingt daher eine sorgfältige Indikationsstellung mit entsprechender Beurteilung von Hart- und Weichgewebe des zu ersetzenden Zahnes und seiner Nachbarzähne. Indiziert das Resultat dieser Beurteilung ein Therapiekonzept zur Optimierung des ästhetischen Gesamtergebnisses, muss ein additives Gewebsmanagement erfolgen. Letzteres macht eine für den jeweiligen Patienten vorteilhafte Auswahl von chirurgischen und/oder kieferorthopädischen Maßnahmen sowie ggf. die Anwendung einer Zahnreplantation notwendig. Zusätzlich ist das Zeitregime der genannten adjuvanten Eingriffe in Relation zur Sofortimplantation und -versorgung zu definieren. Die daraus resultierende Komplexität soll mit Hilfe von in dem Beitrag vorgestellten Entscheidungsbäumen leichter handhabbar und so die Erstellung von fallspezifischen Therapieregimen erleichtert werden. Keywords: Sofortimplantation, Sofortversorgung, Frontzahntrauma, Frontzahnverlust, Zahnreplantation, kieferorthopädische Extrusion, Weichgewebsmanagement, Knochenaugmentation, Therapie-regime, Frontzahnästhetik, entzündliche Extraktionsalveole, Weichgewebsrezession

Aim: The purpose of this literature review is to systematically evaluate the impact of immediate implant placement and restoration (IIPR) on hard and soft tissues and to identify clinical parameters which influence the outcome. Materials and methods: An electronic search of the PubMed database was performed from January 2000 to September 2015. A further hand search was conducted in selected journals and only abstracts published in English were considered for review. Human clinical trials with at least 10 participants and which reported hard and soft tissue outcomes were assessed. Randomised controlled trials (RCT), prospective, prospective comparative and retrospective studies were considered. The effects of the following clinical parameters on hard and soft tissue outcomes were analysed: type of implant, primary stability, gingival biotype, flapless surgery, tooth extraction, spatial arrangement of the implant, socket grafting, the gap between implant surface and alveolar wall and the loading protocol. Results: 17 studies (four RCT, six prospective, two comparative prospective, three controlled cohort and two retrospective studies) were included with 626 censored IIPR in 609 patients. A total of 411(65.56 %) implants were placed flapless vs 215 implants after raising a mucoperiosteal flap. Five studies defined raising a mucoperiostal flap as a mandatory part of the surgical protocol. The mean of the remaining gap in between the implant surface and the alveolar wall, the so-called "jump space", was reported for 170 implants ranging from 1.38 mm to 2.25 mm. Two hundred and one implant sites were not grafted, 405 were grafted, mostly with bone substitutes; for 20 no information was available. For 419 implants, a minimum insertion torque of ≥ 32 Ncm or an ISQ value of ≥ 60 was reached; for 53 implants an insertion torque of 25 Ncm was accepted. The implants were mostly placed palatinally of the jaw bone. The vertical position of the platform was reported either to be 0.5 to 1.0 mm below the vestibular bone crest or 3 to 4 mm apical to the adjacent cementoenamel junction of the neighbouring tooth. Post-insertion healing with a non-functional occlusion occurred for 97.8% of the implants. The final single crowns were inserted 3 to 6 months after implant placement. The IIPR resulted in a high success (97.96 %) and survival rate (98.25%) after a mean followup period of 31.2 months. The soft-tissue biotype was evaluated in 379 (60.5%) sites as thick. The mean crestal bone and the mean interproximal mucosa level changes were less than 1 mm compared to the baseline. The midfacial periimplant mucosal level change was less than 0.95 mm. This level was reached for both thin and thick soft-tissue biotypes, without a significant difference. Only in one study did the thin biotypes show a significantly higher recession. Conclusion: The systematic review revealed promising results for immediately placed and immediately restored implants (IIPR) in the anterior maxilla. The possible options of flapless surgery and absence of grafting of the socket allows a minimal surgical intervention. However, a strict patient selection seemed mandatory for all included clinical trials. Keywords: immediate implant placement, immediate implant restoration, peri-implant tissue remodelling, single-tooth replacement

This report describes the use of laboratory-fabricated crown intaglio replicas for extraorally prepared cementation of fixed restorations to implants. This technique minimizes excess cement and may therefore reduce the risk of cement-related marginal peri-implant bone loss. It is unclear whether the remaining thin layer of luting agent provides sufficient retention if low-adhesive zinc oxide (ZnO) cement is used. In 85 consecutive patients, 113 single crowns were cemented to implants using extraoral cementation technique (ECT) and ZnO cement. All patients were followed for 6 months and investigated for decementation. Seven events of decementation (incidence: 6.19%) were found in 7 patients (8.24%). ECT may represent a viable cementation technique for implant-supported single crowns, even using low-adhesion cements.

Purpose: The purpose of this study was to evaluate the efficacy of the ridge-splitting technique in the anterior maxilla, using piezoelectric surgery for immediate implant placement. Study outcomes were compared with those of implant placement in the same patients using the conventional drilling technique. Materials and Methods: Ten patients received a total of 22 implants in the anterior maxilla, 11 of which were placed using a ridge-splitting procedure (test group) and the other 11 using the conventional drilling procedure (control group). Ridge width (RW), crestal bone level (BL), and implant stability quotient (ISQ) were measured at different points in time. Data were analyzed and compared between the groups using analysis of variance (ANOVA) and paired-sample t tests at a significance level of 5%. Results: For the test group, the gain in RW was not stable in time because at 6 months postoperatively, the RW lost some of the initial gain; however, the net gain was still significant. At 6 months postoperatively, BL was similar for both groups. The net bone loss on the mesial aspect and the average of the mesial and the distal measures did not differ significantly between both groups. ISQ values sharply increased at 3 months postoperatively in the test group. All implants met the modified Albrektsson criteria (1989) for success. Conclusion: The results from this study support the efficacy and safety of ridge expansion using piezoelectric surgery for implant insertion in the anterior maxilla. The modest net gain in bone width suggests that additional hard and soft tissue augmentation may be necessary, especially in the esthetic zone. ISQ values suggest a minimum healing time of 3 months before loading the implants that have been inserted using this ridge-splitting protocol. Keywords: bone expansion, dental implant, piezoelectric surgery, ridge splitting

Purpose: Cementation of implant-supported restorations poses two major challenges: (1) minimizing excess cement (reducing the risk of peri-implantitis), and (2) establishing sufficient retention (reducing the risk of decementation). This study presents the first data on a clinical cementation technique that might address both problems. Materials and Methods: Between 2011 and 2013, 39 patients were provided with 52 implants supporting 52 single crowns (SCs). All restorations were cemented extraorally using replicas made of pattern resin and zinc oxide cement. All decementation events and the peri-implant soft tissue status were assessed and compared with those from a group of 29 patients with 40 conventionally cemented SCs (control). Results: In the experimental group, after 12 months, decementation was recorded in three individuals (7.69%) with 3 SCs (5.77%). In the control group, after 12 months, no case of decementation was recorded. No cases of peri-implantitis were detected in either group. Conclusion: Within the limitations of this study, the authors conclude that the use of zinc oxide cement initially establishes sufficient retention of implant-supported fixed restorations independent of conventional or replica cementation techniques. Keywords: decementation, dental implant, excess cement, single crowns, zinc oxide-noneugenol cement

Teleskopretinierter, implantatgetragener Zahnersatz war lange Zeit aufgrund fehlender geeigneter Behandlungsstrategien sowohl von zahnärztlicher als auch zahntechnischer Seite in der Implantologie vermieden worden. Die notwendige Präzison zur Herstellung einer optimalen Gerüstpassung zur Vermeidung jeglicher Prothesenkinematik ließ die Versorgungsform schnell unwirtschaftlich werden, obwohl die Vorteile für die Geroprothetik auf der Hand liegen: Eine vereinfachte Hygiene und einfache Erweiterbarkeit nach Pfeilerverlust stellen klinisch relevante Vorteile dar. Basierend auf den wissenschaftlichen Arbeiten von Weigl et al. wurde es Mitte der 90er Jahre möglich, durch Galvanomesostrukturen und deren intraorale Verklebung mit der Tertiärstuktur eine spannungsfreie und hochpräzise Gerüstpassung (Spaltbildung < 5 µm) zu erreichen. Dadurch konnte nicht nur das Behandlungsprotokoll vereinfacht, sondern auch der zahntechnische Aufwand wesentlich verringert und dadurch wirtschaftlicher gestaltet werden. Im Mittelpunkt standen die intraorale Verklebung und die Einführung eines neuen Haltelements - das konische Abutment aus Keramik. Bei geriatrischen Lösungsansätzen sind in der Implantatprothetik entweder herausnehmbare oder festsitzende Konstruktionen möglich. Die Entscheidungskriterien für oder gegen festsitzenden Zahnersatz im fortgeschrittenen Alter sind vielschichtig. Von Bedeutung sind Faktoren, wie Atrophiegrad, Implantatanzahl, mögliche Implantatlokalisation, operativer Aufwand, die manuelle und visuelle Fähigkeit des Patienten für die notwendigen Hygienemaßnahmen und letztendlich der finanzielle Aufwand. Festsitzende Konstruktionen ermöglichen die höchste Patientenakzeptanz, sind jedoch im Hygineaufwand seitens der Patienten nicht für jeden handhabbar. Herausnehmbare Implantatkonstruktionen vereinfachen die notwendigen hygienischen Maßnahmen erheblich und sind vor allem bei reduzierter Implantatanzahl und bei Patienten angezeigt, die altersbedingt die hohen hygienischen Anforderungen, die bei festsitzendem Zahnersatz notwendig sind, nicht mehr erfüllen können oder möchten. Bei allen Konstruktionen in der geriatrischen Implantatprothetik darf der Zukunftsaspekt in Bezug auf den Allgemeinzustand des Patienten nicht außer Acht gelassen werden. Unsere Patienten altern mit den Implantatkonstruktionen. Besonders bei der Integration festsitzender Konstruktionen muss diesem Aspekt Rechnung getragen werden. Die Hygienemaßnahmen müssen also im Fall einer Pflegebedürftigkeit durch Dritte erbracht werden können, damit periimplantäre Probleme bis hin zum Implantat- respektive Konstruktionsverlust vermieden werden können. Als Halteelement wählen wir die konische Primärkrone als Patrize; als Matrize fungiert die Galvanomesostruktur, die am Ende der Prothesenherstellung in das Tertiärgerüst eingeklebt wird. Aus hygienischen und mechanischen Gründen kommt als Material für das Halteelement ausschließlich Zirkondioxid zum Einsatz. Die prothetische Konstruktion ist als Einstück-Brückenkonstruktion auf enossalen Implantaten konzipiert und wird zunächst auf den Primärteilen zementiert. Es können verschiede Gerüst- und Verblendmaterialien zum Einsatz kommen. Die Konstruktion sichert folglich die Anpassung an veränderte gesundheitliche Lebensumstände des alternden Patienten und ist ohne Aufwand von der primär festsitzenden Lösung zu einer herausnehmbaren Lösung veränderbar. Keywords: Teleskopretinierter Zahnersatz, Zirkoniumdioxid, implantatgetragener Zahnersatz, Geroprothetik, konisches Abutment, festsitzende Konstruktionen, herausnehmbare Konstruktionen

In einer In-vitro-Studie wurde das dynamische Verhalten unterschiedlich konstruierter Implantat-Abutment-Verbindungen untersucht. Hierbei wurden die Abutments unter 30° mit einer Kraft von bis zu 200 N belastet. Der Kraftangriffspunkt war 8 mm von der Implantatplattform entfernt, die Anstiegsgeschwindigkeit der Kraft betrug 0,3 N/ms. Das Interface der Implantat-Abument-Verbindung wurde röntgenologisch mit einer Videokamera (1.000 Bilder/s) erfasst und vermessen. Die Ergebnisse zeigen, dass unter simulierten klinischen Bedingungen komplexe Mechanismen für die Entstehung oder das Ausbleiben von Mikrobewegungen verantwortlich sind. Sämtliche Implantat-Abutment-Verbindungen ohne Selbsthemmung weisen Mikrobewegungen auf (Implantatsysteme: SIC®, Replace Select®, Camlog®, XIVE®, Straumann-synOkta und -Fräszylinder®, Bego-Semados®, Straumann-Massivsekundärteil®). Bei präzise gefertigten Konusverbindungen mit Selbsthemmung (Implantatsysteme: Ankylos®, Astra Tech®) konnten keine Mikrobewegungen beobachtet werden. Die klinische Relevanz der Ergebnisse kann derzeit jedoch nur theoretisch abgeleitet werden. Vermutlich spielt der durch die Mikrobewegung verursachte Pumpeffekt eine entscheidende Rolle bei der krestalen Knochenresorption. Angenommen wird eine Kontamination des Knochens mit der im Implantat enthaltenen Flüssigkeit. Keywords: Implantat-Abutment-Verbindungen, Stoßverbindungen, Konusverbindungen, Kaubelastung, Kausimulator, Mikrobewegungen