Books

Traditionally, metal-ceramics, metal-reinforced acrylics, and more recently full-contour or layered zirconia have been the materials of choice for definitive fixed implant-supported rehabilitations. Polymethyl Methacrylate (PMMA) is commonly used in implant dentistry for the fabrication of implant-supported interim prostheses and as milled or 3D printed prototypes. This article describes a novel protocol to prosthetically restore a completely edentulous patient following a digital workflow, with fixed, screw-retained, implant-supported prostheses fabricated from CAD/CAM milled polymethyl methacrylate (PMMA), with no metal substructure. After two years follow up in terms of esthetics, phonetics, function and biological tissue response, the outcome remains functional and free of mechanical, biomechanical or biological complications. The aim of this article is to illustrate the feasibility of using milled PMMA as viable definitive prosthetic material for the fixed implant rehabilitation of edentulous patients. Keywords: milled-PMMA, Implant-supported prostheses, long-term implant-retained restorations, CAD-CAM milled restoration

Introduction: The interforaminal region is considered more favorable for implant placement than the posterior mandible in edentulous patients, mainly because of the interference of the inferior alveolar nerve with implant placement in the severely resorbed posterior mandible. However, complications in the interforaminal region may occur due to the presence of the mandibular incisive nerve. Objective: This scoping review aims to describe the mandibular incisive nerve anatomy related to the potential interference in implant therapy. Material and methods: A comprehensive literature search was conducted in the following databases: MEDLINE (via PubMed), Web of Science, and Scopus. This scoping review was structured according to the Joanna Briggs Institute method. Results: Thirteen studies were included in the review. All the studies were observational cohort anatomical studies, carried out mainly by CBCT and on cadavers. A total of 1471 patients/cadavers were studied. The mandibular incisive nerve was presented in 87-100% of the cases, with an average length of 9.97 mm and an average diameter of 1.97 mm. The mandibular incisive nerve may be damaged during drilling and implant placement, especially using implant lengths larger than 12 mm. Conclusions: Damage to the mandibular incisive nerve due to implant placement could be present, however, it is necessary to conduct more studies focusing on assessing mandibular incisive nerve damage to understand the clinical relevance of this nerve and its associated morbidities such as neurosensorial alterations. Due to the different anatomical characteristics of this nerve, CBCT analysis is recommended for implant therapy in the anterior mandible to prevent the described complications.

In der vorliegenden Fallserie sollten Einflussfaktoren für die erfolgreiche Eingliederung CAD/CAM-gefertigter implantatgetragener Provisorien untersucht werden, die auf Grundlage einer virtuell geplanten Implantatposition vor der digital navigierten Implantatinsertion hergestellt werden. Die Daten wurden an Patienten gewonnen, bei denen für eine erforderliche Einzelzahn-Implantatversorgung eine digitale Volumentomografie (DVT) und Intraoralscans in eine Implantatplanungssoftware importiert wurden. Ein Synchronisationstool stellte die Verbindung zwischen der Implantatplanungs- und der CAD-Software her, in der eine digitale diagnostische Zahnaufstellung mit passenden Zahndimensionen und adäquater Weichgewebearchitektur erstellt wurde. Anschließend wurden die virtuelle Implantatplanung abgeschlossen und die geplante Implantatposition in die CAD-Software übertragen, wo eine Restauration konstruiert und zur Herstellung geschickt wurde. Nach der navigierten Implantatinsertion wurde das vorgefertigte Provisorium noch am Tag der Implantatsetzung oder, wenn eine verzögerte Belastung oder gedeckte Implantateinheilung indiziert war, nach der Heilungsphase eingesetzt. Die Auswertung erfolgte mittels deskriptiver Statistik und Z-Test für zwei Proportionen. Insgesamt 23 Patienten mit 28 Einzelimplantatstellen erfüllten die Einschlusskriterien und wurden in die Studie inkludiert. Neunzehn individuelle Gingivaformer und 10 provisorische Kronen für insgesamt 29 Restaurationen wurden digital konstruiert und hergestellt. Für die verglichenen Variablen fanden sich keine statistisch signifikanten Unterschiede. Das Fazit: Auf einer virtuell geplanten Implantatposition basierende, individuell vorgefertigte CAD/CAM-Implantatprovisorien lassen sich erfolgreich konstruieren, herstellen und eingliedern, wenn die Implantation navigiert erfolgt. Originalpublikation: Hamilton et al. „Digitally Fabricated Provisional Implant Restorations Prior to Implant Placement: A Clinical Case Series.” (Int J Prosthodont 2022;35:94–108)1. Keywords: digitaler Workflow, CAD/CAM, Provisorium, Gingivaformer, Einzelimplantat, Implantatplanung, navigierte Implantation, DVT, Planungssoftware

This case report describes a new digital workflow for computer-assisted implant surgery in an edentulous patient using transitional implants to support a fixed surgical template and interim prosthesis. The accuracy of the final implant position using the described protocol was evaluated and compared to the outcomes obtained using other types of surgical templates. This novel digital approach appears to enhance the accuracy of implant positioning for edentulous patients and seems to be comparable to a tooth-supported surgical template.

Purpose: This study aimed to assess the influence of implant diameter and taper on the proximity of virtually planned maxillary central incisor implants to the nasopalatine canal and adjacent anatomical structures. Materials and methods: Virtual implant planning was performed in the maxillary central incisor position. The distance between the implant and the incisive canal (IC) and the thickness of the surrounding buccal and palatal bone walls were measured. Implants were categorized as having an exposed implant surface, thin bone, or moderate/thick bone. Measurements were repeated for regular-/narrow-diameter and parallel/tapered implants. Results: A total of 60 patients were included, and 240 implants (60 of each type: 3.3-bone level [BL], 3.3-bone level tapered [BLT], 4.1-BL, and 4.1-BLT) were planned. The percentages of implants with between 0 and 0.5 mm of remaining bone in the coronal aspect of the IC were 31.6% for 4.1-BL/BLT and 6.6% for 3.3-BL/BLT (P < .001). The percentage of implants with IC exposure was 13.3% for 4.1-BL/BLT and 6.6% for 3.3-BL/BLT (P < .001). The frequency of sites that required bone augmentation at the coronal facial aspect (< 1 mm) was 52.6% and 33.9% for 4.1-BL/BLT and 3.3-BL/BLT, respectively. At the apical portion, the percentages of sites requiring bone augmentation at the facial aspect were 59.9%, 49.9%, 31.6%, and 23.3% for 4.1-BL, 3.3-BL, 4.1-BLT, and 3.3-BLT, respectively (P < .001). Conclusion: The proximity of the nasopalatine canal is often < 0.5 mm from regular-diameter virtually planned implants at the most coronal aspect in the maxillary central incisor position. In these situations, the selection of narrowdiameter implants significantly lowers the incidence of implant exposure and the need for additional management of the nasopalatine canal and also results in greater residual buccal and lingual bone thicknesses surrounding the implant. As expected, tapered implants reduced the risk of implant exposure through the buccal cortex at the apical aspect. Keywords: diagnostic procedure, epidemiology, single implant, virtual reality

Purpose: To review the factors that affect the ability to deliver a CAD/CAM implant-supported provisional restoration designed from a virtually planned implant position prior to surgical placement with static computer-assisted implant surgery (sCAIS). Materials and methods: Data were collected on patients treated with single-tooth implant treatment in which CBCT was combined with intraoral scans and imported into a virtual implant planning software. A synchronization tool established the connection between the planning software and the CAD software, where a digital diagnostic tooth arrangement was performed to create the ideal tooth dimensions and mucosal architecture. The virtual implant planning was finalized, and the implant position was transferred to the CAD software, where a restoration was designed and fabricated. The sCAIS was performed, and the prefabricated custom restorations were delivered on the day of the surgery or following healing if delayed loading or submerged healing was required. Descriptive statistics and statistical comparison with two-proportion z test were performed. Results: A total of 23 patients with 28 single-implant sites met the inclusion criteria and were included in the study. Nineteen customized healing abutments and 10 provisional crowns were designed and fabricated for a total of 29 restorations. Of the restorations, 23 were successfully delivered on the day of the surgical intervention. No statistical significance was found among the different variables compared. Conclusion: Custom prefabricated CAD/CAM restorations based on a virtually planned implant position can be successfully designed, fabricated, and delivered when used in combination with sCAIS.

Sinus floor elevation with the lateral window approach has proven to be an effective treatment modality for vertical bone augmentation in the posterior region of the maxilla. The simultaneous implant placement during the procedure can be achieved if enough remaining bone height is available to obtain implant primary stability. However, the proper identification of the maxillary sinus boundaries for the window demarcation along with membrane protection for simultaneous implant placement can be challenging. This clinical report demonstrates a novel technique for sinus floor augmentation using a 3D modified implant-osseous-membrane surgical template to assist in the lateral window demarcation, membrane stabilization and protection, and guided implant placement in a partially edentulous patient who was eligible for one-stage sinus floor elevation. The surgical procedure for the sinus demarcation is simplified, the membrane stabilization and protection are effective, and the guided implant placement provided a predictable surgical positioning of the implants. Keywords: CAD/CAM, guided implant surgery, guided sinus floor elevation, sinus floor elevation, 3D printing

This case report describes a digital workflow for a computer-aided design/computer-assisted manufacturing (CAD/CAM) healing abutment used in immediate implant placement in the esthetic zone. The design of the healing abutment was based on the existing tooth anatomy in order to provide anatomical support to the gingival tissues and to preserve the gingival contours of the natural tooth. This approach enhances the esthetic outcome of the definitive implant restoration. The surgical procedure including the guided bone regeneration is simplified, postoperative morbidity is reduced, and excessive occlusal loading during healing is limited. Keywords: CAD/CAM healing abutment, computer-guided surgery, immediate implant placement

Viele Behandlungen schadhafter oder fehlender Zähne in der ästhetischen Zone erfordern eine Versorgung mit provisorischem Zahnersatz vor oder nach dem Implantationseingriff. Der Beitrag erörtert die verschiedenen Arten von Provisorien sowie ihre Vor- und Nachteile im Rahmen von Rehabilitationen in ästhetisch wichtigen Bereichen. Keywords: provisorischer Zahnersatz, Implantation, Gewebemanagement, Übergangszone

Diese Studie sollte die Passform von CAD/CAM-gefertigten Implantatabutments eines bestimmten Anbieters mit herstellergebundenen konfektionierten Abutments auf verschiedenen Implantatsystemen vergleichen. Auf fünf verschiedenen Implantattypen wurden CAD/CAM-gefertigte Titanabutments mit konfektionierten Abutments verglichen. Die Prüfkörper wurden in Epoxidharz eingebettet, ein Längsschnitt wurde hergestellt und poliert. Die Abstände (Spaltbreiten) zwischen Implantaten und Abutments wurde an den horizontalen (Flanschen) und den internen vertikalen Komponenten rasterelektronenmikroskopisch vermessen. Beim Vergleich der Messwerte wurde der t-Test für unabhängige Stichproben eingesetzt. Keywords: Implantatprothetik, CAD/CAM-gefertigte Implantatabutments, konfektionierte Implantatabutments, Passform, Spaltbreiten