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Objectives: The aim of this study was to assess the antibacterial efficacy of nanostructured dental implant surfaces against Porphyromonas gingivalis, a crucial bacterium in the progression of peri-implantitis. Additionally, to evaluate the possible effect of the modified implant surface on the viability of human gingival fibroblasts (HGnFs). Method and materials: As detailed in prior research, helium ions sputtering was used to produce nanospiked titanium surfaces with a height of 1000 nm (Ti1000). Smooth machined (Ti machined) and SLA titanium disks (TiSLA) served as controls. The antibacterial characteristics of the samples against P. gingivalis were evaluated by conventional culturing and SEM. The vitality of HGnFs was assessed using the MTT assay. Results: Generally, nanostructured Ti1000 surfaces exhibited less bacterial counts than the two controls (Ti1000 vs TiSLA -36% and Ti1000 vs Ti machined -37%.) without being statistically significant. Moreover, the nanosurface did not affect the vitality of HGnFs. Conclusion: The nanospikes of the modified titanium implant surface did not hinder gingival fibroblasts' vitality or proliferation characteristics. Optimizing the spacing and height parameters of the nanospikes could further improve the antibacterial effects of this unique re-modification approach. Parole chiave: abutment design, adhesion, dental implants, implants, microbiology, peri-implantitis

In dieser Studie sollten durchmesserreduzierte und Standarddurchmesser-Implantate im Oberkiefer-Frontzahnbereich hinsichtlich ihrer ästhetischen und funktionellen Ergebnisse und der Patientenzufriedenheit bei einer Nachuntersuchung nach 1−6 Jahren verglichen werden. Die Studie war als retrospektive Kohortenstudie angelegt und schloss 27 Patienten ein, bei denen Einzelimplantate mit 3,3 mm Durchmesser (Narrow-diameter implant, NDI, n = 14) oder mit 4,1 mm Durchmesser (Standard-diamter implant, SDI, n = 16) im Oberkiefer-Frontzahnbereich eingesetzt worden waren. Die beiden Gruppen wurden mittels deskriptiver und analytischer statistischer Auswertung der klinischen Untersuchungsergebnisse zu den Parametern ästhetisches Ergebnis, Fließrate der Sulkusflüssigkeit (Sulcus Fluid Flow Rate, SFFR), Kronenästhetik, Patientenzufriedenheit (visuelle Analogskala, VAS), Auftreten biologischer/technischer Komplikationen, Sondierungstiefen (Exakter Fisher-Test), Pink Esthetic Score (PES) sowie Periotest (Mann-Whitney-U-Test) miteinander verglichen. Der mittlere Beobachtungszeitraum lag in der NDI-Gruppe bei 4,8 Jahren, in der SDI-Gruppe bei 4,9 Jahren nach Eingliederung der Kronen. Ein signifikanter Unterschied zugunsten der 4,1-mm-Implantate fand sich für den Periotest-Wert (p = 0,014). Dagegen waren die Unterschiede bei der Ästhetik (PES, p = 0,27), der SFFR (p = 0,73) und den Sondierungstiefen (p = 0,35) nicht signifikant. Die Patientenzufriedenheit war mit VAS-Werten von 9,3 ± 1,1 in der NDI- und 9,4 ± 1,0 in der SDI-Gruppe für beide Gruppen hoch (p = 0,39). Die klinischen Ergebnisse von durchmesserreduzierten und Standarddurchmesser-Implantaten im Oberkiefer-Frontzahnbereich waren vergleichbar. Manuskripteingang: 31.12.2021, Annahme: 31.01.2022 Originalbeitrag: Momberger et al. (Quintessence Int 2022;53:502–509). Parole chiave: Implantate, durchmesserreduzierte Implantate, Oralchirurgie, Pink Esthetic Score

Objective: The aim of this study was to evaluate functional and esthetic clinical outcomes and patient satisfaction with narrow-diameter implants in comparison to standard-diameter implants in the anterior zone of the maxilla in a follow-up examination after 1 to 6 years. Method and materials: The study was designed as a retrospective cohort study investigation including 27 patients receiving a 3.3-mm diameter single implant (NDI, n = 14) or a standard-diameter 4.1-mm single implant in the anterior zone of the maxilla (SDI, n = 16). Descriptive and analytical statistics were performed comparing both groups with regard to clinical examination including esthetic outcome, sulcus fluid flow-rate, crown esthetics, patients’ satisfaction on visual analog scales, occurrence of biologic or technical complication, probing pocket depths (Fisher exact test), pink esthetic score (PES) and Periotest (Mann-Whitney U test). The level of significance was set at α = .05. Results: The mean observation period was 4.8 years after crown insertion in the NDI group, and 4.9 years in the SDI group. Significant differences were observed for Periotest values in favor of the 4.1-mm implants (P = .014). No differences were found with regards to esthetics (PES; P = .27) or sulcus fluid flow-rate (P = 0.73) and probing pocket depths (P = .35). Overall patient satisfaction was high for both groups with visual analog scale scores of 9.3 ± 1.1 for NDI and 9.4 ± 1.0 for SDI (P = .39). Conclusion: Clinical outcome with narrow-diameter implants was comparable to standard-diameter implants in the anterior zone of the maxilla with similar esthetic assessments and patients’ satisfaction. Parole chiave: implants, narrow-diameter implants, oral surgery, pink esthetic score

Purpose: The aim of this in vitro study was to evaluate the temperature development of a novel, electropolished drill design during conventional and guided implant osteotomy in comparison to conventional drills under standardized conditions. Materials and methods: Single and sequential 12-mm-deep drilling protocols (guided and unguided) with a conventional (control groups) and novel drill (test groups) were performed in artificial bone blocks under external irrigation. Each drilling protocol was repeated 30 times with drill diameters of 2.2, 2.8, 3.5, and 4.2 mm. Temperature changes were recorded by an infrared camera, and the accumulated thermal energy was calculated. For group comparison, a one-way analysis of variance (ANOVA) and Tukey post hoc test were used with a level of significance set to = .05. Results: The highest temperatures were measured up to 77.9°C for small-diameter drills in the control and test groups. The 3.5-mm and 4.2-mm novel drills showed significantly lower heat generation during guided and unguided osteotomy preparation for single and sequential drilling. The accumulated thermal energy during guided osteotomy preparation was significantly lower with the electropolished drills. Conclusion: The drill design has an important impact on heat development during osteotomy, which was most pronounced for guided osteotomy with conventional drills and for small-diameter osteotomies. Parole chiave: drill design, electrochemical polishing, guided surgery, heat generation, infrared camera, sequential drilling, single drilling, temperature measurement, twist drills

Die chronisch granulierende Entzündung nach Partsch mit extraoralem Fistelgang ist eine eher selten gewordene Manifestation einer chronischen dentogenen Infektion. In Abwesenheit von Symptomen kann die korrekte Diagnose erschwert sein, weil Patienten häufig beim Hausarzt oder Dermatologen vorstellig werden und somit eine dentogene Ursache nicht unmittelbar in Betracht gezogen wird. Der Beitrag beschreibt die Behandlung einer 34-jährigen, gesunden Patientin, die sich aufgrund einer Hauteffloreszenz im Bereich der rechten Wange vorstellte. Parole chiave: Fistulierung, extraorale Fistel, Hauteffloreszenz, dentogener Fokus, Fehldiagnose

Dislokationsverletzungen führen häufig zu einer Kalzifizierung des Wurzelkanalsystems. Wenn aufgrund einer apikalen Parodontitis eine endodontische Behandlung notwendig ist, kann die Wurzelkanalsuche selbst für Spezialisten mit Operationsmikroskop eine Herausforderung darstellen. Unter Verwendung einer dreidimensionalen radiologischen Bildgebung und eines digitalen Oberflächenscans lässt sich mit der entsprechenden Software virtuell ein optimaler Zugang zum Wurzelkanal planen. Diese "Guided Endodontics"-Technik wird mit Hilfe von Bohrschablonen analog der geführten Implantologie umgesetzt. Der Beitrag erläutert den erfolgreichen Einsatz der Technik anhand eines Falles, in dem ein kalzifizierter Wurzelkanal zuvor mit konventionellen Verfahren nicht erschlossen werden konnte. Parole chiave: "Guided Endodontics", Obliteration, geführte Wurzelkanalbehandlung, Bohrschablone, 3-D-Druck

Purpose: The purpose of this study was to evaluate whether fully digitally guided implant surgery may be performed with sufficient accuracy based on printing virtually designed templates after matching a surface scan with the magnetic resonance imaging (MRI) dataset mimicking edentulous cases based on cadaver maxillae of pigs. Materials and Methods: The palatal mucosa of five young pig cadavers was scanned with an intraoral scanner. High-resolution MRI of the jaws was performed, and the images were exported as DICOM files and uploaded into software for implant planning. Six implant osteotomies were virtually planned in each jaw. The intraoral surface scans were fused with the volumetric MRI data based on the palatal soft tissue, and virtual templates for guided implant surgery were created and exported as STL files. These were printed and the templates were used to perform flapless guided osteotomy, with the templates fitting on the soft tissue of the jaws alone. Cone beam computed tomography (CBCT) of the jaws was performed after osteotomy. These data were fused with the virtually planned osteotomies, and the 3D crestal, apical, and axial deviations between the virtually planned and physically performed osteotomies were determined. Results: Matching the surface scans with the mucosa was possible in three cases automatically; additional manual corrections were necessary in two cases. Thirty osteotomies were performed by applying the printed mucosa-supported templates. The mean angular deviation between the planned and realized cavities was 3.29 degrees (0.3 to 11.1 degrees; SD = 2.5 degrees), the mean 3D apical deviation was 1.3 mm (0.22 to 3.98 mm; SD = 0.94 mm), and the mean crestal deviation was 1.76 mm (0.39 to 3.79 mm; SD = 0.88 mm). Conclusion: MRI in combination with the presented workflow may be used in edentulous cases for guided implant surgery. Further studies are needed to prove the promising accuracy of this alternative approach in clinical trials. Parole chiave: cone beam computed tomography (CBCT), guided implant surgery, magnetic resonance imaging (MRI), ultra-short echo time (UTE), zero echo time (ZTE)

Purpose: To evaluate whether removing a fractured abutment screw with a specific rescue device negatively affects the success of a new restoration in terms of early abutment loosening. Materials and Methods: Implants (n = 10) with a regular platform of 4.1 mm (tissue level [TL]) and implants (n = 10) with a reduced diameter of 3.3 mm (bone level [BL]) were used. The screws of eight respective abutments for both implant types were artificially weakened in order to fracture during torque application for abutment insertion. The fractured abutment screws were removed applying a specific rescue kit. The implant inner threads were cleaned and remodeled with a system-specific tapper. New abutments were inserted, and computer-aided design/computer-aided manufactured (CAD/CAM) full zirconia crowns were luted. Aging by thermal cycling and mechanical loading was performed with a customized masticator simulator, and the number of crown and/ or abutment loosenings was determined. In cases in which no loosening was observed, sawing and grinding were performed to determine the contact zone between the inner implant thread and abutment screw. Data were compared with a control group, eg, unmodified implant-abutment connections. Results: No abutment loosening was observed. All crowns were in function after mastication simulation. The inner thread contact zones of both test groups were generally smaller than in the control group, with a mean contact area of 448.6 μm and 459 μm for BL implants, and 608.8 μm and 620.5 μm for the TL implants in test and control groups, respectively. Conclusion: Removing a fractured abutment screw with a specific rescue device and modifying the inner thread seems not to negatively affect the functional connection between a new abutment and the implant. Parole chiave: CAD/CAM, mastication, screw, torque, zirconia crowns

Purpose: To compare the suitability of a fused filament fabrication (FFF) consumer 3D printer with a professional digital light processing (DLP) printer for the production of surgical templates for guided oral implant surgery. Materials and Methods: Eight virtual templates were printed with two different 3D printers. These were optically scanned and the incongruences between virtual and printed templates were determined after alignment of the surface scans and the virtual data. Minimum, maximum, and mean incongruences were determined, and a t test between both groups was performed to determine statistically significant differences in accuracy. Results: Templates printed with the professional DLP printer showed statistically significantly less incongruence (P = .001) than those fabricated by the consumer FFF 3D printer. Conclusion: The accuracy of manufactured templates is strongly dependent on the printing device and method. At this time, the tested consumer 3D FFF printer is not suitable for the fabrication of templates for implant guided surgery. Minimum requirements regarding printers' features and 3D-printed templates need to be assessed in future studies. Parole chiave: accuracy, additive manufacturing, guided surgery, oral implantology, 3D printing

Die endodontische Behandlung von Zähnen mit obliterierten Wurzelkanälen und Parodontitis apicalis stellt oft eine Herausforderung für Generalisten und Spezialisten dar. Ein hoher Zeitaufwand für die Wurzelkanalsuche und das erhöhte Risiko einer Perforation können die endodontische Therapie verkomplizieren. Mithilfe der dreidimensionalen radiologischen Bildgebung und einer digitalen Abformung der entsprechenden Kieferregion lässt sich für derart schwierige Fälle eine schablonengeführte Technik der Wurzelkanalbehandlung ("Guided Endodontics") klinisch umsetzen. Im folgenden Beitrag wird die Planung und Durchführung von "Guided Endodontics" an einem oberen Eckzahn beschrieben, bei dem der obliterierte Wurzelkanal lokalisiert und eine Perforation vermieden werden konnte. Parole chiave: Kalzifikation, Pulpaobliteration, apikale Parodontitis, minimalinvasive Trepanation, "Guided Endodontics"